If one had the Plutonium or Uranium how hard would it be to construst a nuclear device? From what I have read it really doesn't sound that difficult, especially a gun type. I think the implosion type device would be more of a challenge.
I have no interest in building such a thing but I was thinking if a terrorist group was to obtain the fissionable material it might not be too difficult for them to do it.
What do you guys think?

I've read conflicting reports concerning how easily obtainable plutonium/uranium is. I've also read that traditional purification systems required the government to set up miles of subterranean pipelines.

To construct a basic U-235 device, you would need QUITE an amount of uranium, and some U-238 to act as a neutron-deflecting fission plate. A gun type device would be simple enough to construct, you just need sufficient force to propel the smaller amount into the larger base, achieving critical mass.

A plutonium implosion type device would be MUCH harder to construct. You would need to cut 32 identical sphere-wedges of it and separate them with (I believe) beryllium. A charge must be placed behind on each wedge to force it inward, thus creating a critical plutonium mass. While this method is more effective if you have the means, most terrorists just don't.

The gun type is feasible, if you managed to obtain the U-235. I've read one report of a man stealing near-weaponsgrade uranium right out of huge drums outside a nuclear power plant. I've also seen what United Nuclear (<a href="http://www.unitednuclear.com/" target="_blank">http://www.unitednuclear.com/</a>) charges for uranium samples. Even though uranium and its oxide are not (to my knowledge) restricted or monitored in any regular sense, if you buy a hundred kilograms of uranium, expect a spook knocking on your door.

<small>[ February 27, 2003, 05:30 PM: Message edited by: Ezekiel Kane ]</small>

You need nearly pure u-235 for atomic bombs, not u-238. I read somehere about a 15 year old kid who made nearly pure u-235 in his shed. So it cant be the difficult to produce. Ill see if I can find anything intresting on extracting it.

[He did not make nearly pure U-235, not even close. If it was that easy nukes would be springing up all over the place.]
[Sorry confused U-233 with U-235.]

<small>[ March 02, 2003, 07:28 PM: Message edited by: NERV ]</small>

IMO, it's highly unlikely a terrorist could build a nuke. A Uranium device requires several tens of kilos of weapons grade U, which isn't exactly easy to get hold of. And then the two or more subcritical masses must be forced together quickly enough to produce a complete fission. If an incomplete fission occurs, there will be a small explosion, and most of the U will be scattered around like a dirty bomb.

As for a Plutonium device, this would be far too difficult for the average bomb maker to construct. Someone used to making pipe bombs full of TNT extracted from anti-tank mines just won't have the skill, even with the resources. A clever nuclear physicist would be required for this, and a lot of money.

Even if a terrorist group did build a bomb, there's a high chance it wouldn't work. You can't exactly use trial and error with these!

I'm much more worried about the electronics failing in some dilapidated Soviet missile silo and one of these being fired by accident.

NERV,

That 15-year old kid who "extracted uranium" in his shed wouldn't happen to have been "radioactive Boy Scout" David Hahn, would it have? Because while he had quite a few interesting things stored in his mothers' potting shed (pure radium extracted from radium watch hands, a quarter of his Pontiac's trunkload of pitchblende, americium from hundreds of smoke detectors, thorium that was hundreds of times purer than that found anywhere in nature, and lithium that he was using to purify the thorium) but no uranium-235 (besides the minute quantities in the pitchblende. He tried (and failed) to make a breeder reactor with the radioactive materials he had. Howevr, what interests me most was his procedure for obtaining thorium from gas mantles (and yes, I know that the newer gas mantles contain no thorium, but there are still hundreds of thousands of older mantles around). If one were to use a simple barium or lithium based purification process like he did, one could concievably get nearly pure thorium 232, which can be converted to uranium 233, which can be used in a gun-type bomb just like U-235. This process would require thousands of gas mantles and hundreds of lithium batteries (these were the source David Hahn used for his lithium; it might be easier to just purchase lithium if it isn't particularly restricted, or buy it as the bromide/chloride salt as a pool chemical and extract the lithium from that) but has the advantage of not requiring the purchase of any uranium or uranium compounds. Oh, and lest anyone say that the thorium to uranium process would never work, it was the process North Korea planned to use back in the late 1950's to procure fuel for its reactors (Korea has considerable thorium reserves), and they abadoned it not because it was unworkable, but because the Soviets basically just gave them the technology for heavy water uranium fueled reactors, along with the needed uranium. Finally, if anyone would like the full story of the "radioactive Boy Scout" and the methods/techniques he used fro obtaining and extracting his radioactives, I can post it here. I have the full version from Harper's magazine; the one from Reader's Digest and most online versions are heavily edited.

Yea it was the David Hahn kid. I think he made his U-233 by bombarding thorium 232 with neutrons. Its nothing to complex, the only problem is getting enough materials to do it. His neutron gun was made of a lead block filled with Radium; a tiny hole in the front was covered with Beryllium to produce neutrons. I am not sure though as to what he used to slow the neutrons down.

Can the gun type Nuke be made from Pu?
you need less Pu per kiloton yield than a uranium nuke IIRC

<a href="http://www28.brinkster.com/emcatalouge/file/atomh.html" target="_blank">http://www28.brinkster.com/emcatalouge/file/atomh.html</a>

Yeah, excuse me - I put U-238 where I should have put U-235 and vice versa. It's fixed now.

If it is not too much trouble, I would be interested in the articles.

Since the premise was if you had the uranium/plutonium, I'd say it would be fairly simple to build a nuke.

Given enough U235 that is :) If you're got enough then you wouldn't even have to worry about setting up the neutron reflector correctly (or having one at all). All you'd need is the explosives and electronic detonation that many of us here "play" with on a regular basis.

I think many of the people on this forum would be sucessful first time in building a large U235 gun-type device. Pu implosion type, I would fancy our chances :) Even the Americans weren't sure if it'd work till it touched down on Japan...

If (and that's a BIG if) you had the fissile material needed, I think a gun-type would be well within reach. The US was sure enough it would work that they didn't even test it first. It was just an AA gun barrel 3in in diamater with the plug fired into the target with smokeless powder. Im not sure if it had a neutron emitter or not, but that probably wouldnt be too hard.

Ok, here's the article:

Harper's Magazine Nov, 1998 The radioactive boy scout: when a teenager attempts to build a breeder reactor. (case of David Hahn who managed to secure materials and equipment from businesses and information from government officials to develop an atomic energy radiation project for his Boy Scout merit-badge)

Author/s: Ken Silverstein When a teenager attempts to build a breeder reactor

Golf Manor is the kind of place where nothing unusual is supposed to happen, the kind of place where people live precisely because it is more than 25 miles outside of Detroit and all the complications attendant in that city. The kind of place where money buys a bit more land, perhaps a second bathroom, and so reassures residents that they're safely in the bosom of the middle class. Every element of Golf Manor invokes one form of security or another, beginning with the name of the subdivision itself--taken from the 18 hole course at its entrance--and the community in which it is nestled, Commerce Township. The houses and trees are both old and varied enough to make Golf Manor feel more like a neighborhood than a subdivision, and the few features that do convey subdivision--a sign at the entrance saying "We have many children but none to spare. Please drive carefully"--have a certain Back to the Future charm. Most Golf Manor residents remain there until they die, and then they are replaced by young couples with kids. In short, it is the kind of place where, on a typical day, the only thing lurking around the corner is a Mister Softee ice-cream truck. But June 26, 1995, was not a typical day. Ask Dottie Pease. As she turned down Pinto Drive, Pease saw eleven men swarming across her carefully manicured lawn. Their attention seemed to be focused on the back yard of the house next door, specifically on a large wooden potting shed that abutted the chain-link fence dividing her property from her neighbor's. Three of the men had donned ventilated moon suits and were proceeding to dismantle the potting shed with electric saws, stuffing the pieces of wood into large steel drums emblazoned with radioactive warning signs. Pease had never noticed anything out of the ordinary at the house next door. A middle-aged couple, Michael Polasek and Patty Hahn, lived there. On some weekends, they were joined by Patty's teenage son, David. As she huddled with a group of nervous neighbors, though, Pease heard one resident claim to have awoke late one night to see the potting shed emitting an eerie glow. "I was pretty disturbed," Pease recalls. "I went inside and called my husband. I said, `Da-a-ve, there are men in funny suits walking around out here. You've got to do something.'" What the men in the funny suits found was that the potting shed was dangerously irradiated and that the area's 40,000 residents could be at risk. Publicly, the men in white promised the residents of Golf Manor that they had nothing to fear, and to this day neither Pease nor any of the dozen or so people I interviewed knows the real reason that the Environmental Protection Agency briefly invaded their neighborhood. When asked, most mumble something about a chemical spill. The truth is far more bizarre: the Golf Manor Superfund cleanup was provoked by the boy next door, David Hahn, who attempted to build a nuclear breeder reactor in his mother's potting shed as part of a Boy Scout merit-badge project.

It seems remarkable that David's story hasn't already wended its way through all forms of journalism and become the stuff of legend, but at the time the EPA refused to give out David's name, and although a few local reporters learned it, neither he nor any family members agreed to be interviewed. Even the federal and state officials who oversaw the cleanup learned only a small part of what took place in the potting shed at Golf Manor because David, fearing legal repercussions, told them almost nothing about his experiments. Then in 1996, Jay Gourley, a correspondent with the Natural Resources News Service in Washington, D.C., came across a tiny newspaper item about the case and contacted David Hahn. Gourley later passed on his research to me, and I subsequently interviewed the story's protagonists, including David--now a twenty-two-year-old sailor stationed in Norfolk, Virginia. I met with David in the hope of making sense not only of his experiments but of him. The archetypal American suburban boy learns how to hit a fadeaway jump shot, change a car's oil, perform some minor carpentry feats. If he's a Boy Scout he masters the art of starting a fire by rubbing two sticks together, and if he's a typical adolescent pyro, he transforms tennis-ball cans into cannons. David Hahn taught himself to build a neutron gun. He figured out a way to dupe officials at the Nuclear Regulatory Commission into providing him with crucial information he needed in his attempt to build a breeder reactor, and then he obtained and purified radioactive elements such as radium and thorium. I had seen childhood photographs of David in which he looked perfectly normal, even angelic, with blond hair and hazel-green eyes, and, as he grew older, gangly limbs and a peach-fuzz mustache. Still, when I went to meet him in Norfolk, I was anticipating some physical manifestation of brilliance or obsession. An Einstein or a Kaczynski. But all I saw was a beefier version of the clean-cut kid in the pictures. David's manner was oddly dispassionate, though polite, until we began to discuss his nuclear adventures. Then, for five hours, lighting and grinding out cigarettes for emphasis, David enthused about laboring in his backyard laboratory. He told me how he used coffee filters and pickle jars to handle deadly substances such as radium and nitric acid, and he sheepishly divulged the various cover stories and aliases he employed to obtain the radioactive materials. A shy and withdrawn teenager, David had confided in only a few friends about his project and never allowed anyone to witness his experiments. His breeder-reactor project was a means--albeit an unorthodox one--of escaping the trauma of adolescence. "I was very emotional as a kid," he told me, "and those experiments gave me a way to get away from that. They gave me some respect."

David's parents, Ken and Patty Hahn, divorced when he was a toddler. Ken is an automotive engineer for General Motors, as is his second wife, Kathy Missig, whom he married soon after the divorce. David lived with his father and stepmother in a small split-level home in suburban Clinton Township, about thirty miles north of Detroit. Ken Hahn worked extraordinarily long hours for GM. With close-cropped hair and a proclivity for short-sleeved dress shirts, Ken radiates a coolness that, combined with his constant preoccupation, must have been confounding to a child. When asked about his undemonstrative nature, Ken attributes it to his German ancestry. Yet for all his starchiness, it was Kathy who was David's chief disciplinarian. David spent weekends and holidays with his mother and her boyfriend, Michael Polasek, an amiable but hard-drinking retired forklift operator at GM. Golf Manor is demographically similar to Clinton Township, but the two households could not have been more different emotionally. Patty Hahn committed suicide in the house a few years ago, but Michael still lives there surrounded by pictures of her. ("She was a beautiful person," he says. "She was my whole life.") He keeps five cats and a spotless household, and looks like a member of Sha Na Na. Despite the fact that David was shuffled between households, his early years were seemingly ordinary. He played baseball and soccer, joined the Boy Scouts, and spent endless hours exploring with his friends. An abrupt change came at the age of ten, when Kathy's father, also an engineer for GM, gave David The Golden Book of Chemistry Experiments. The book promised to open doors to a brave new world--"Chemistry means the difference between poverty and starvation and the abundant life," it stated with unwavering optimism--and offered instructions on how to set up a home laboratory and conduct experiments ranging from simple evaporation and filtration to making rayon and alcohol. David swiftly became immersed and by age twelve was digesting his father's college chemistry textbooks without difficulty. When he spent the night at Golf Manor, his mother would often wake to find him asleep on the livingroom floor surrounded by open volumes of the Encyclopedia Britannica. In his father's house, David set up a laboratory in his small bedroom, where the shelves are still lined with books such as Prudent Practices for Handling Hazardous Chemicals in Laboratories and The Story of Atomic Energy. He bought beakers, Bunsen burners, test tubes, and other items commonly found in a child's chemistry set. David, though, was not conducting the typical adolescent experiments. By fourteen, an age at which most boys with a penchant for chemistry are conducting rudimentary gunpowder experiments, David had fabricated nitroglycerine. David's parents admired his interest in science but were alarmed by the chemical spills and blasts that became a regular event at the Hahn household. After David destroyed his bedroom--the walls were badly pocked, and the carpet was so stained that it had to be ripped out--Ken and Kathy banished his experiments to the basement.

Which was fine with David. Science allowed him to distance himself from his parents, to create and destroy things, to break the rules, and to escape into something he was a success at, while sublimating a teenager's sense of failure, anger, and embarrassment into some really big explosions. David held a series of after-school jobs at fast-food joints, grocery stores, and furniture warehouses, but work was merely a means of financing his experiments. Never an enthusiastic student and always a horrific speller, David fell behind in school. During his junior year at Chippewa Valley High School--at a time when he was secretly conducting nuclear experiments in his back yard--David nearly failed state math and reading tests required for graduation (though he aced the test in science). Ken Gherardini, who taught David conceptual physics, remembers him as an excellent pupil on the rare occasions when he was interested in classwork but otherwise indifferent to his studies. "His dream in life was to collect a sample of every element on the periodic table," Gherardini told me with a laugh during an interview at Chippewa Valley before his 8:20 A.M. class. "I don't know about you, but my dream at that age was to buy a car." David's scientific preoccupation left less and less time for friends, though throughout much of high school he did have a girlfriend, Heather Beaudette, three years his junior. Heather says he was sweet and caring (she once returned from a weeklong trip to Florida to find a pile of lengthy love letters) but not always the perfect date. Heather's mom, Donna Bunnell, puts it this way: "He was a nice kid and always presentable, but we had to tell him not to talk to anybody. He could eat and drink but, for God's sake, don't talk to the guests about the food's chemical composition." Not even his scout troop was spared David's scientific enthusiasm. He once appeared at a scout meeting with a bright orange face caused by an overdose of canthaxanthin, which he was taking to test methods of artificial tanning. One summer at scout camp, David's fellow campers blew a hole in the communal tent when they accidentally ignited the stockpile of powdered magnesium he had brought to make fireworks. Another year, David was expelled from camp when--while most of his friends were sneaking into the nearby Girl Scouts' camp--he stole a number of smoke detectors to disassemble for parts he required for his experiments. "Our summer vacation was screwed up when we got a call telling us to pick David up early from camp," his stepmother recalls with a sigh. Up to this point the most illicit of David's concoctions were fireworks and moonshine. But convinced that David's experiments and increasingly erratic behavior were signs that he was making and selling drugs, Ken and Kathy began to spot-check the public library, where David told them he studied. Invariably, David would be there as promised, surrounded by a huge pile of chemistry books. But Ken and Kathy were not assuaged, and, worried that he would level their home, they prohibited David from being there alone, locking him out when they were away, even on quick errands, and setting a time for their return so that he could get back in. Kathy began routinely searching David's room and disposing of any chemicals and equipment she found hidden under the bed and deep within the closet.

David was not deterred. One night as Ken and Kathy were sitting in the living room watching TV, the house was rocked by an explosion in the basement. There they found David lying semiconscious on the floor, his eyebrows smoking. Unaware that red phosphorus is pyrophoric, David had been pounding it with a screwdriver and ignited it. He was rushed to the hospital to have his eyes flushed, but even months later David had to make regular trips to an ophthalmologist to have pieces of the plastic phosphorus container plucked carefully from his eyes. Kathy then forbade David from experimenting in her home. So he shifted his base of operations to his mother's potting shed in Golf Manor. Both Patty Hahn and Michael Polasek admired David for the endless hours he spent in his new lab, but neither of them had any idea what he was up to. Sure, they thought it was odd that David often wore a gas mask in the shed and would sometimes discard his clothing after working there until two in the morning, but they chalked it up to their own limited education. Michael says that David tried to explain his experiments but that "what he told me went right over my head." One thing still sticks out, though. David's potting-shed project had something to do with creating energy. "He'd say, `One of these days we're gonna run out of oil.' He wanted to do something about that."

Like Michael, few people whom David confided in understood what he was doing. Ken Hahn, who had taken chemistry courses in college, could follow some of what David told him but thought he was exaggerating for attention. "I never saw him turn green or glow in the dark," he says. "I was probably too easy on him." It probably didn't feel that way to David. Although Ken is immensely proud of David's experiments now that they have a certain notoriety, at the time they represented a breakdown in discipline. As fathers are wont to do, Ken felt the solution lay in a goal that he didn't himself achieve as a child--Eagle Scout. As teenagers are wont to do, David subverted that goal. In addition to showing "scout spirit," Eagle Scouts must earn twenty-one merit badges. Eleven are mandatory, such as First Aid and Citizenship in the Community. The final ten are optional; scouts can choose from dozens of choices ranging from American Business to Woodwork. David elected to earn a merit badge in Atomic Energy. His scoutmaster, Joe Auito, who lives on a rural road an hour or so north of Detroit and who resembles an aging Deadhead rather than the rock-ribbed conservative I'd expected, says he's the only boy to have done so in the history of Clinton Township Troop 371. David's Atomic Energy merit-badge pamphlet was brazenly pro-nuclear, which is no surprise since it was prepared with the help of Westinghouse Electric, the American Nuclear Society, and the Edison Electric Institute, a trade group of utility companies, some of which run nuclear power plants. The pamphlet judiciously states that America is a democracy and "the people decide what the country will do." The pamphlet goes on to suggest, however, that critics of atomic energy were descended from a long line of naysayers and malcontents, warning that "if America decides for or against nuclear power plants based on fear and misunderstanding, that is wrong. We must first know the truth about atomic energy before we can decide to use it or to stop it."

David was awarded his Atomic Energy merit badge on May 10, 1991, five months shy of his fifteenth birthday. To earn it he made a drawing showing how nuclear fission occurs, visited a hospital radiology unit to learn about the medical uses of radioisotopes,(1) and built a model reactor using a juice can, coat hangers, soda straws, kitchen matches, and rubber bands. By now, though, David had far grander ambitions. As Auito's wife and troop treasurer, Barbara, recalls: "The typical kid [working on the merit badge] would have gone to a doctor's office and asked about the X-ray machine. Dave had to go out and try to build a reactor." What is a breeder reactor? This simplistic description comes from a publication that David obtained from the Department of Energy (DOE): "Imagine you have a car and begin a long drive. When you start, you have half a tank of gas. When you return home, instead of being nearly empty, your gas tank is full. A breeder reactor is like this magic car. A breeder reactor not only generates electricity, but it also produces new fuel." All reactors, conventional and breeder, rely on a critical pile of a naturally radioactive element--typically uranium-235 or plutonium-239--as the "fuel" for a sustained chain of reactions known as fission. Fission occurs when a neutron combines with the nucleus of a radioisotope, say uranium-235, transforming it into uranium-236. This new isotope is highly unstable and immediately splits in half, forming two smaller nuclei, and releasing a great deal of radiant energy (some of which is heat) and several neutrons. These neutrons are absorbed by other uranium-235 atoms to begin the process again. A breeder reactor is configured so that a core of plutonium-239 is surrounded by a "blanket" of uranium-238. When the plutonium gives off neutrons, they are absorbed by the uranium-238 to become uranium-239, which in turn decays by emitting beta rays and is transformed into neptunium-239. Following another stage of "radioactive decay," neptunium becomes plutonium-239, which can replenish the fuel core. The nuclear industry used to tout breeders as the magical solution to the nation's energy needs. The government had opened up two experimental breeders at a test site in Idaho by 1961. Amid great fanfare, in 1963 Detroit Edison opened the Enrico Fermi I power plant, the nation's first and only commercially run breeder reactor. The following decade, Congress appropriated billions of dollars for the Clinch River Breeder Reactor in Tennessee. Hopes ran so high that Glenn Seaborg, chairman of the Atomic Energy Commission during the Nixon years, predicted that breeders would be the backbone of an emerging nuclear economy and that plutonium might be "a logical contender to replace gold as the standard of our monetary system." Such optimism proved to be unwarranted. The first Idaho breeder had to be shut down after suffering a partial core meltdown; the second breeder generated electricity but not new fuel. The Fermi plant--located just 60 miles from Clinton Township--was plagued by mechanical problems, accidents, and budget overruns, and produced electricity so expensive that Detroit Edison never even bothered to break down the costs. In 1966, the plant's core suffered a partial meltdown after the cooling system malfunctioned; six years later the plant was shut down permanently. In 1983, when it was estimated that completion costs would deplete much of the federal budget for energy research and development, Congress finally killed the Clinch River program.

If he knew of such setbacks, David was in no way deterred by them. His inspiration came from the nuclear pioneers of the late nineteenth and early twentieth centuries: Antoine Henri Becquerel, the French physicist who, along with Pierre and Marie Curie, received the Nobel Prize in chemistry in 1903 for discovering radioactivity; Fredic and Irene Joliot-Curie, who received the prize in 1935 for producing the first artificial radioisotope; Sir James Chadwick, who won the Nobel Prize in physics the same year for discovering the neutron; and Enrico Fermi, who created the world's first sustainable nuclear chain reaction, a crucial step leading to the production of atomic energy and atomic bombs.(2) Unlike his predecessors, however, David did not have vast financial support from the state, no laboratory save for a musty potting shed, no proper instruments or safety devices, and, by far his chief impediment, no legal means of obtaining radioactive materials. To get around this last obstacle, David utilized a number of cover stories and concocted identities, plus a Geiger-counter kit he ordered from a mail-order house in Scottsdale, Arizona, which he assembled and mounted to the dashboard of his burgundy Pontiac 6000. David hadn't hit on the idea to try to build a breeder reactor when he began his nuclear experiments at the age of fifteen, but in a step down that path, he was already determined to "irradiate anything" he could. To do that he had to build a "gun" that could bombard isotopes with neutrons. David wrote to a number of groups listed in his merit-badge pamphlet--the DOE, the Nuclear Regulatory Commission (NRC), the American Nuclear Society, the Edison Electric Institute, and the Atomic Industrial Forum, the nuclear-power industry's trade group--in hopes of discovering how he might obtain, from both natural and commercial sources, the radioactive raw materials he needed to build his neutron gun and experiment with it. By writing up to twenty letters a day and claiming to be a physics instructor at Chippewa Valley High School, David says he obtained "tons" of information from those and other groups, though some of it was of only marginal value. The American Nuclear Society sent David a teacher's guide called "Goin' Fission," which featured an Albert Einstein cartoon character: "I'm Albert. Und today, ve are gonna go fission. No, ve don't need any smelly bait and der won't be any fish to clean. I mean fission, not fishin'." Other organizations proved to be far more helpful, and none more than the NRC. Again posing as a physics teacher, David managed to engage the agency's director of isotope production and distribution, Donald Erb, in a scientific discussion by mail. Erb offered David tips on isolating certain radioactive elements, provided a list of isotopes that can sustain a chain reaction, and imparted a piece of information that would soon prove to be vital to David's plans: "Nothing produces neutrons ... as well as beryllium." When David asked Erb about the risks posed by such radioactive materials, the NRC official assured "Professor Hahn" that the "real dangers are very slight," since possession "of any radioactive materials in quantities and forms sufficient to pose any hazard is subject to Nuclear Regulatory Commission (or equivalent) licensing." David says the NRC also sent him pricing data and commercial sources for some of the radioactive wares he wanted to purchase, ostensibly for the benefit of his eager students. "The NRC gave me all the information I needed," he later recalled. "All I had to do was go out and get the materials."

Armed with information from his friends in government and industry, David typed up a list of sources for fourteen radioactive isotopes..Americium-241, he learned from the Boy Scout atomic-energy booklet, could be found in smoke detectors; radium-226, in antique luminous dial clocks; uranium-238 and minute quantities of uranium-235, in a black ore called pitchblende; and thorium-232, in Coleman-style gas lanterns. To obtain americium-241, David contacted smoke-detector companies and claimed that he needed a large number of the devices for a school project. One company agreed to sell him about a hundred broken detectors for a dollar apiece. (He also tried to "collect" detectors while at scout camp.) David wasn't sure where the americium-241 was located, so he wrote to BRK Electronics in Aurora, Illinois. A customer-service representative named Beth Weber wrote back to say she'd be happy to help out with "your report." She explained that each detector contains only a tiny amount of americium-241, which is sealed in a gold matrix "to make sure that corrosion does not break it down and release it." Thanks to Weber's tip, David extracted the americium components and then welded them together with a blowtorch. As it decays, americium-241 emits alpha rays composed of protons and neutrons. David put the lump of americium inside a hollow block of lead with a tiny hole pricked in one side so that alpha rays would stream out. In front of the lead block he placed a sheet of aluminum. Aluminum atoms absorb alpha rays and in the process kick out neutrons. Since neutrons have no charge, and thus cannot be measured by a Geiger counter, David had no way of knowing whether the gun was working until he recalled that paraffin throws off protons when hit by neutrons. David aimed the apparatus at some paraffin, and his Geiger counter registered what he assumed was a proton stream. His neutron gun, crude but effective, was ready. With neutron gun in hand, David was ready to irradiate. He could have concentrated on transforming previously nonradioactive elements, but in a decision that was both indicative of his personality and instrumental to his later attempt to build a breeder reactor, he wanted to use the gun on radioisotopes to increase the chances of making them fissionable. He thought that uranium-235, which is used in atomic weapons, would provide the "biggest reaction." He scoured hundreds of miles of upper Michigan in his Pontiac looking for "hot rocks" with his Geiger counter, but all he could find was a quarter trunkload of pitchblende on the shores of Lake Huron. Deciding to pursue a more bureaucratic approach, he wrote to a Czechoslovakian firm that sells uranium to commercial and university buyers, whose name was provided, he told me, by the NRC. Claiming to be a professor buying materials for a nuclear-research laboratory, he obtained a few samples of a black ore--either pitchblende or uranium dioxide, both of which contain small amounts of uranium-235 and uranium-238.

David pulverized the ores with a hammer, thinking that he could then use nitric acid to isolate uranium. Unable to find a commercial source for nitric acid--probably because it is used in the manufacture of explosives and thus is tightly controlled--David made his own by heating saltpeter and sodium bisulfate, then bubbling the gas that was released through a container of water, producing nitric acid. He then mixed the acid with the powdered ore and boiled it, ending up with something that "looked like a dirty milk shake." Next he poured the "milk shake" through a coffee filter, hoping that the uranium would pass through the filter. But David miscalculated uranium's solubility, and whatever amount was present was trapped in the filter, making it difficult to purify further. Frustrated at his inability to isolate sufficient supplies of uranium, David turned his attention to thorium-232, which when bombarded with neutrons produces uranium-233, a man-made fissionable element (and, although he might not have known it then, one that can be substituted for plutonium in breeder reactors). Discovered in 1828 and named after the Norse god Thor, thorium has a very high melting point, and is thus used in the manufacture of airplane engine parts that reach extremely high temperatures. David knew from his merit-badge pamphlet that the "mantle" used in commercial gas lanterns--the part that looks like a doll's stocking and conducts the flame--is coated with a compound containing thorium-232. He bought thousands of lantern mantles from surplus stores and, using the blowtorch, reduced them into a pile of ash. David still had to isolate the thorium-232 from the ash. Fortunately, he remembered reading in one of his dad's chemistry books that lithium is prone to binding with oxygen--meaning, in this context, that it would rob thorium dioxide of its oxygen content and leave a cleaner form of thorium. David purchased $1,000 worth of lithium batteries and extracted the element by cutting the batteries in half with a pair of wire cutters. He placed the lithium and thorium dioxide together in a ball of aluminum foil and heated the ball with a Bunsen burner. Eureka! David's method purified thorium to at least 9,000 times the level found in nature and 170 times the level that requires NRC licensing. At this point, David could have used his americium neutron gun to transform thorium-232 into fissionable uranium-233. But the americium he had was not capable of producing enough neutrons, so he began preparing radium for an improved irradiating gun. Radium was used in paint that rendered luminescent the faces of clocks and automobile and airplane instrument panels until the late 1960s, when it was discovered that many clock painters, who routinely licked their brushes to make a fine point, died of cancer. David began visiting junkyards and antiques stores in search of radium-coated dashboard panels or clocks. Once he found such an item, he'd chip paint from the instruments and collect it in pill vials. It was slow going until one day, driving through Clinton Township to visit his girlfriend, Heather, he noticed that his Geiger counter went wild as he passed Gloria's Resale Boutique/Antique. The proprietor, Gloria Genette, still recalls the day when she was called at home by a store employee who said that a polite young man was anxious to buy an old table clock with a tinted green dial but wondered if she'd come down in price. She would. David bought the clock for $10. Inside he discovered a vial of radium paint left behind by a worker either accidentally or as a courtesy so that the clock's owner could touch up the dial when it began to fade. David was so overjoyed that he dropped by the boutique later that night to leave a note for Gloria, telling her that if she received another "luminus [sic] clock" to contact him immediately. "I will pay any some [sic] of money to obtain one."

To concentrate the radium, David secured a sample of barium sulfate from the X-ray ward at a local hospital (staff there handed over the substance because they remembered him from his merit-badge project) and heated it until it liquefied. After mixing the barium sulfate with the radium paint chips, he strained the brew through a coffee filter into a beaker that began to glow. This time, David had judged the solubility of the two substances correctly; the radium solution passed through to the beaker. He then dehydrated the solution into crystalline salts, which he could pack into the cavity of another lead block to build a new gun. Whether David fully realized it or not, by handling purified radium he was truly putting himself in danger. Nevertheless, he now proceeded to acquire another neutron emitter to replace the aluminum used in his previous neutron gun. Faithful to Erb's instructions, he secured a strip of beryllium (which is a much richer source of neutrons than aluminum) from the chemistry department at Macomb Community College--a friend who attended the school swiped it for him--and placed it in front of the lead block that held the radium. His cute little americium gun was now a more powerful radium gun. David began to bombard his thorium and uranium powders in the hopes of producing at least some fissionable atoms. He measured the results with his Geiger counter, but while the thorium seemed to grow more radioactive, the uranium remained a disappointment. Once again, "Professor Hahn" sprang into action, writing his old friend Erb at the NRC to discuss the problem. The NRC had the answer. David's neutrons were too "fast" for the uranium).(3) He would have to slow them down using a filter of water, deuterium, or tritium. Water would have sufficed, but David likes a challenge. Consulting his list of commercially available radioactive sources, he discovered that tritium, a radioactive material used to boost the power of nuclear weapons, is found in glow-in-the-dark gun and bow sights, which David promptly bought from sporting-goods stores and mail-order catalogues. He removed the tritium contained in a waxy substance inside the sights, and then, using a variety of pseudonyms, returned the sights to the store or manufacturer for repair--each time collecting another tiny quantity of tritium. When he had enough, David smeared the waxy substance over the beryllium strip and targeted the gun at uranium powder. He carefully monitored the results with his Geiger counter over several weeks, and it appeared that the powder was growing more radioactive by the day. Now seventeen, David hit on the idea of building a model breeder reactor. He knew that without a critical pile of at least thirty pounds of enriched uranium he had no chance of initiating a sustained chain reaction, but he was determined to get as far as he could by trying to get his various radioisotopes to interact with one another. That way, he now says, "no matter what happened there would be something changing into something--some kind of action going on there." His blueprint was a schematic of a checkerboard breeder reactor he'd seen in one of his father's college textbooks. Ignoring any thought of safety, David took the highly radioactive radium and americium out of their respective lead casings and, after another round of filing and pulverizing, mixed those isotopes with beryllium and aluminum shavings, all of which he wrapped in aluminum foil. What were once the neutron sources for his guns became a makeshift "core" for his reactor. He surrounded this radioactive ball with a "blanket" composed of tiny foil-wrapped cubes of thorium ash and uranium powder, which were stacked in an alternating pattern with carbon cubes and tenuously held together with duct tape.

David monitored his "breeder reactor" at the Golf Manor laboratory with his Geiger counter. "It was radioactive as heck," he says. "The level of radiation after a few weeks was far greater than it was at the time of assembly. I know I transformed some radioactive materials. Even though there was no critical pile, I know that some of the reactions that go on in a breeder reactor went on to a minute extent." Finally, David, whose safety precautions had thus far consisted of wearing a makeshift lead poncho and throwing away his clothes and changing his shoes following a session in the potting shed, began to realize that, sustained reaction or not, he could be putting himself and others in danger. (One tip-off was when the radiation was detectable through concrete.) Jim Miller, a nuclear-savvy high-school friend in whom David had confided, warned him that real reactors use control rods to regulate nuclear reactions. Miller recommended cobalt, which absorbs neutrons but does not itself become fissionable. "Reactors get hot, it's just a fact," Miller, a nervous, skinny twenty-two-year-old, said during an interview at a Burger King in Clinton Township where he worked as a cook. David purchased a set of cobalt drill bits at a local hardware store and inserted them between the thorium and uranium cubes. But the cobalt wasn't sufficient. When his Geiger counter began picking up radiation five doors down from his mom's house, David decided that he had "too much radioactive stuff in one place" and began to disassemble the reactor. He placed the thorium pellets in a shoebox that he hid in his mother's house, left the radium and americium in the shed, and packed most of the rest of his equipment into the trunk of the Pontiac 6000.

At 2:40 A.M. on August 31, 1994, the Clinton Township police responded to a call concerning a young man who had been spotted in a residential neighborhood, apparently stealing tires from a car. When the police arrived, David told them he was waiting to meet a friend. Unconvinced, officers decided to search his car. When they opened the trunk they discovered a toolbox shut with a padlock and sealed with duct tape for good measure. The trunk also contained over fifty foil-wrapped cubes of mysterious gray powder, small disks and cylindrical metal objects, lantern mantles, mercury switches, a clock face, ores, fireworks, vacuum tubes, and assorted chemicals and acids.The police were especially alarmed by the toolbox, which David warned them was radioactive and which they feared was an atomic bomb. For reasons that are hard to fathom, Sergeant Joseph Mertes, one of the arresting officers, ordered a car containing what he noted in his report was "a potential improvised explosive device" to be towed to police headquarters. "It probably shouldn't have been done, but we thought that the car had been used in the commission of a crime," Police Chief Al Ernst now says sheepishly. "When I came in at 6:30 in the morning it was already there."

The police called in the Michigan State Police Bomb Squad to examine the Pontiac and the State Department of Public Health (DPH) to supply radiological assistance. The good news, the two teams discovered, was that David's toolbox was not an atomic bomb. The bad news was that David's trunk did contain radioactive materials, including concentrations of thorium--"not found in nature, at least not in Michigan"--and americium. That discovery automatically triggered the Federal Radiological Emergency Response Plan, and state officials soon were embroiled in tense phone consultations with the DOE, EPA, FBI, and NRC. With the police, David was largely uncooperative and taciturn. He provided his father's address but didn't mention his mother's house or his potting-shed laboratory. It wasn't until Thanksgiving Day that Dave Minnaar, a DPH radiological expert, finally interviewed David. David told Minnaar that he had been trying to make thorium in a form he could use to produce energy and that he hoped "his successes would help him earn his Eagle Scout status." David also finally admitted to having a backyard laboratory. On November 29, state radiological experts surveyed the potting shed. They found aluminum pie pans, jars of acids, Pyrex cups, milk crates, and other materials strewn about, much of it contaminated with what subsequent official reports would call "excessive levels" of radioactive material, especially americium-241 and thorium-232. How high? A vegetable can, for example, registered at 50,000 counts per minute--about 1,000 times higher than normal levels of background radiation. But although Minnaar's troops didn't know it at the time, they conducted their survey long after David's mother, alerted by Ken and Kathy and petrified that the government would take her home away as a result of her son's experiments, had ransacked the shed and discarded most of what she found, including his neutron gun, the radium, pellets of thorium that were far more radioactive than what the health officials found, and several quarts of radioactive powder. "The funny thing is," David now says, "they only got the garbage, and the garbage got all the good stuff." After determining that no radioactive materials had leaked outside the shed, state authorities sealed it and petitioned the federal government for help. The NRC licenses nuclear plants and research facilities and deals with any nuclear accidents that take place at those sites. David, of course, was not an NRC-licensed operation, so it was determined that the EPA, which responds to emergencies involving lost or abandoned atomic materials, should be contacted for assistance. In a memo to the EPA's Emergency Response and Enforcement Branch, the Department of Public Health noted that the materials discovered in David's lab were regulated under the Federal Atomic Energy Act and that the "extent of the radioactive material contamination within a private citizen's property beg for a controlled remediation that is beyond our authority or resources to oversee."

EPA officials arrived in Golf Manor on January 25, 1995--five months after David had been stopped by the police--to conduct their own survey of the shed. Their "action memo" noted that conditions at the site "present an imminent and substantial endangerment to public health or welfare or the environment," and that there was "actual or potential exposure to nearby human populations, animals, or food chain...." The memo further stated that adverse conditions such as heavy wind, rain, or fire could cause the "contaminants to migrate or be released." A Superfund cleanup took place between June 26 and 28 at a cost of about $60,000. After the moon-suited workers dismantled the potting shed with electric saws, they loaded the remains into thirty-nine sealed barrels placed aboard a semitrailer bound for Envirocare, a dump facility located in the middle of the Great Salt Lake Desert. There, the remains of David's experiments were entombed along with tons of low-level radioactive debris from the government's atomic-bomb factories, plutonium-production facilities, and contaminated industrial sites. According to the official assessment, there was no noticeable damage to flora or fauna in the back yard in Golf Manor, but 40,000 nearby residents could have been put at risk during David's years of experimentation due to the dangers posed by the release of radioactive dust and radiation. Last May, I made the 90-mile drive from Detroit to Lansing, where Dave Minnaar works in a dreary building that houses several state environmental agencies. Because Patty Hahn had cleaned out the shed before Minnaar's men arrived on the scene, he never knew that David had built neutron guns or that he had obtained radium. Nor did he understand, until I told him, that the cubes of thorium powder found by police at the time of David's arrest were the building blocks for a model breeder reactor. "These are conditions that regulatory agencies never envision," says Minnaar. "It's simply presumed that the average person wouldn't have the technology or materials required to experiment in these areas."

David went into a serious depression after the federal authorities shut down his laboratory. Years of painstaking work had been thrown in the garbage or buried beneath the sands of Utah. Students at Chippewa Valley had taken to calling him "Radioactive Boy," and when his girlfriend, Heather, sent David Valentine's balloons at his high school, they were seized by the principal, who apparently feared they had been inflated with chemical gases David needed to continue his experiments. In a final indignity, some area scout leaders attempted (and failed) to deny David his Eagle Scout status, saying that his extracurricular merit-badge activities had endangered the community.

In the fall of 1995, Ken and Kathy demanded that David enroll in Macomb Community College. He majored in metallurgy but skipped many of his classes and spent much of the day in bed or driving in circles around their block. Finally, Ken and Kathy gave him an ultimatum: Join the armed forces or move out of the house. They called the local recruiting office, which sent a representative to their house or called nearly every day until David finally gave in. After completing boot camp last year, he was stationed on the nuclear-powered USS Enterprise aircraft carrier. Alas, David's duties, as a lowly seaman, are of the deck-swabbing and potato-peeling variety. But long after his shipmates have gone to sleep, David stays up studying topics that interest him--currently steroids, melanin, genetic codes, antioxidants, prototype reactors, amino acids, and criminal law. And it is perhaps best that he does not work on the ship's eight reactors, for EPA scientists worry that his previous exposure to radioactivity may have greatly cut short his life. All the radioactive materials he experimented with can enter the body through ingestion, inhalation, or skin contact and then deposit in the bones and organs, where they can cause a host of ailments, including cancer. Because it is so potent, the radium that David was exposed to in a relatively small, enclosed space is most worrisome of all. Back in 1995, the EPA arranged for David to undergo a full examination at the nearby Fermi nuclear power plant. David, fearful of what he might learn, refused. Now, though, he's looking ahead. "I wanted to make a scratch in life," he explains when I ask him about his early years of nuclear research. "I've still got time. I don't believe I took more than five years off of my life."

(1) Individual atoms of an element have the same number of protons in their nuclei. This "atomic number" determines the element's chemical properties and position in the periodic table. The number of neutrons within atoms of the same elements can vary, however. Known as isotopes, these variations have unique physical properties because the number of neutrons affects the atom's mass. Most elements have at least two naturally occurring, stable isotopes. But isotopes of heavier elements (those with more protons) are often unstable. Called radioisotopes, and often artificially produced, these nuclei undergo some form of radioactive decay--alpha, beta, or gamma--to become more stable. In alpha decay, the nucleus loses two protons and two neutrons, thus transforming into another element two atomic numbers below it on the periodic table. In beta decay, either a neutron is converted into a proton, and the atomic number rises, or the opposite occurs, pushing the atomic number down. Gamma radiation--in which energy is emitted but no transformation occurs--can accompany alpha or beta decay (where the atomic number falls) or can occur on its own. Americium-241, for example, is a radioisotope of americium. Its atomic number is 95, its atomic mass number is 241, and it becomes neptunium-237 through alpha decay.

(2) Another role model, similar to David in temperament, was the Englishman Francis William Aston. He invented the mass spectrograph in 1920, which he used to identify more than 200 isotopes. As a child, writes Richard Rhodes, Aston "made picric-acid bombs from soda-bottle cartridges and designed and launched huge tissue-paper fire balloons...." (3) Manhattan Project scientists discovered that some neutrons can move at speeds of about 17 million miles per hour. If they are slowed down or "moderated," to about 5,000 miles per hour, they have a better chance of being absorbed by another atom. Ken Silverstein's last article for Harper's Magazine, "The Boeing Formation," appeared in the May 1997 issue. He lives in Washington, D.C.

spydamonkee-A gun type bomb almost certainly [i]can be made from plutonium-239. The Manhattan Project's scientists probably chose not to do this because of the fact that such a bomb would be far too alreg for an airplane of that time to carry. The problem was this: plutonium gave off more neutrons than U-235. Far more. So much so, that in a "Little Boy" gun-type bomb, the chain reaction would be started by stray neutrons emitted before the pieces of plutonium even came together and formed a critical mass (i.e neutrons from the piece of plutonium traveling toward the target piece would iniate fission while only partway down the gun barrel, causing the bomb to "fizzle"). The scientists had determined that this could be corrected by having a larger and more powerful explosive charge, combined with a longer gun barrel, and thus the plutonium projectile would be traveling at a much higher velocity, and reach the plutonium target before it could be bombarded by too many stray neutrons. However, in order to do this, it was calaculated a barrel distance of anywhere from 19 to 25 feet (there were several different estimates) would be needed. That was for the barrel alone, and not counting the outer casing, radar fuse, tail fins, space for both plutonium projectiles (additional lengths of barrel would be needed for them), and room for the powder charge that would fire the plutonium projectile. Weight and more importantly, length considerations made putting such a device into a bomb that could easily be carried in an aircraft nearly impossible (remember, the Enola Gay and Bock's Car, the B-29's that carried the bombs, both had to have their bomb bays modified just to carry Little Boy and Fat Man). Besides, by 1944 scientists had developed the plutonium implosion system and were relatively sure it would work. Had they not, and had we had the gigantic B-36 by the end of WWII, there might have been a plutonium gun-type bomb, but we didn't, and so the plutonium implosion design was chosen for the second atom bomb. Finally, most of this information on plutonium gun-type bombs came from a book called "US Nuclear Weapons: A pictorial and history" or something like that. I seem to remember my library having it, I'll check it out and see if I can find any additional relevant or useful information (this book is LOADED with all sorts of info and plenty of juicy technical specs on every type of nuclear and thermonuclear weapon design configuration available).

<small>[ February 27, 2003, 09:07 PM: Message edited by: A43tg37 ]</small>

Obviously a gun design has significant advantages in simplicity and
reliability, however there are other designs out there than just spherical implosion devices and gun-types. For instance a Planar Implosion system could be used, that is instead of using common propellents to accelerate an Uranium/Plutonium bullet down a barrel, an explosive charge can be used in conjunction with a flying plate (Used to create a planar, or flate, consistent shockwave) to propel a flat Uranium/Plutonium mass towards another mass of Uranium/Plutonium. The result would be an insertion times several magnitudes higher than even the fastest gun driven divices. Unfortunantly, one may expect rather low efficiency yeilds with this option (Though it may be offset with fusion boosting.)

Another Implosion device that interests me would be the Cylindrical Implosion system, which would use a series of flying plates along the outside perimiter of the Cylinder to create a uniform Imploding shock wave. This regular shockwave would then implode a hollow cylinder of Uranium/Plutonium to Critical mass.These devices have been used before (I forget which tests) and, with fusion boosting, it would likely approach the efficiency found in todays spherical Implosion devices.
Any of these methods for implosion could, with reasonable research, be developed by a forum member (Though the fabrication of the core, tamper, and reflector would provide quite a challange.) If you wish to learn about the concepts and designs of nukes, visit the Nuclear Weapons FAQ at <a href="http://nuketesting.enviroweb.org/hew/Nwfaq/Nfaq0.html" target="_blank">http://nuketesting.enviroweb.org/hew/Nwfaq/Nfaq0.html</a>
the author does a much better job at demonstrating the workings of these devices than I can.

<small>[ February 28, 2003, 12:08 AM: Message edited by: mrcfitzgerald ]</small>

Thats fascinating, but if he knew so much, why didnt he take the time to protect himself? :confused:

A makeshift lead poncho and changing clothes afterwards?? <img border="0" title="" alt="[Eek!]" src="eek.gif" />

That article also states that he made nitric acid by mixing KN03 and sodium bisulfate, heating it and bubling the gas through water, that would be a very cheap method, has anyone tried it?

Green Beret - I have a swimming pool and you can buy large 10Kg buckets of sodium bisulfate for lowering the Ph. They should be available from large supermarkets/hardware shops or pool shops. Pool shops (in Australia anyway) are usually VERY suspicious of anyone buying anything :( .

Thanks xyz, yeah pool shops are real bastards, a better place for sodium bisulfate is Big-W its about ten dollars for three kilos.

"It's simply presumed that the average person wouldn't have the technology or materials required to experiment in these areas."

Translation:

"The average sheeple is content with the mind destroying drivel we put out on TV, and thus is no longer capable of independant thought, rendering them harmless as a threat to our continued reign of despotic power."

I dont know much about chemristy well i know basicly nothing so can u guys explain this in laymans terms Also i have wondered for a few years about Americum being used in bombs i was thinking more along the lines of dirty bombs Could this be done if your had a significant amount of it or can americum be used easly to make a preriqsite for a dirty bomb ?

I would like to state that i hav no intentions of making a dirty bomb i am only asking from ceurosity

Explain chemistry to you in lay-man's terms? Would you also like the Internet on CDROM?

If you had read the most recent thread in Battlefield Chemistry (let alone done a search), your question would have been answered in full.

How you figured that using americum for dirty bombs fitted into the topic of "nukes", I have no idea.

Be gone, and READ!

"Dirty Bombs" - that would be a civilian term. The correct name for such a device is a neutron bomb or an "ER" warhead (enhanced radiation).

well actually enhanced radiation weapons and neutron bombs are not simply dirty bombs. they are precise weapons. the neutron bomb releases a vast amount of neutron radiation where as the enhanced radiation weapon is a small nuclear warehead which typically has a low yield but releases a relatively large amount of fallout of a short half life. the surrounding area is thus cleansed of life allowing friendly troops to take over most buildings relatively intact after a week or so once a sufficient number of hlaf lives have passed (usually 4). these weapons are refered to as dirty because they typically have a large amount of fallout.
a 'dirty bomb' however refers to the scattering of radioactive materla using conventional explosives.

You are right and I wish to thank you for correcting me there <img border="0" title="" alt="[Wink]" src="wink.gif" /> , but that was posted in response to the earlier one. You can be as specific as you want in this field but to expand on what you said earlier: </font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">the neutron bomb releases a vast amount of neutron radiation where as the enhanced radiation weapon is a small nuclear warehead which typically has a low yield but releases a relatively large amount of fallout of a short half life.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">1. an ER warhead is a neutron bomb in most senses,
2. they both give off neutron radiation (in general terms),
3. and the ER warhead (salted device) can have variable half lives depending on what it is "salted" with. The longest half life salting agent, Zinc-64, had a half life of 244 days (wich depending on you view is long or short). But in a war zone wich this was intended to be employed in (against tank crews) 244 days or more is a lot of time too wait for an area to decontaminate to reasonable levels.
&gt;Again "dirty bomb" and neutron bomb ect. are general terms and you can get very specific with them

<small>[ March 09, 2003, 03:01 PM: Message edited by: Ghostcustom 24 ]</small>

On the issue of "Dirty bombs". Yes the word dirty bomb is a media buzzword at the momment. There are four types of weapons that the term can relate too,

1. A radioactive dispersion device wich only spreads radioactive material by explosive force -There is no nuclear explosion-

2. A "Neutron bomb" though this is not in the true sense a dirty bomb (as it does not release as much fallout per given yeild as does a normal fusion device) it does release a deadly flux of neutrons that can kill up to twice the range as a normal bomb of comparable yeild. This type of weapon was envisioned in order to effectivly and immediatly eliminate a T-82 tank charge, as the neutron flux could take them out far more efficiently than normal blast effects.
-This is a nuclear bomb-

3. A "salted device" which uses a blanket of radioactive material surrounding a fusion core (This is the core of the fusion part of the Teller-Ullam device). It is designed to decrease the immediate danger of the fall out but increase the length of time a given area stays radioactive.
-This is a nuclear bomb-

4. A "dirty bomb" is commonly used to show a difference between a Teller-Ullam device with a fissionable (U-238 or HEU) jacket surrounding the fusion fuel, or a non fissionable material such as lead. -This is a nuclear bomb-

As for the mention of the Enhanced Radiation device, it usually is used to talk about a Neutron Bomb as it enhances the initial radiation pulse in order to maximize killing via radiation.

<small>[ March 07, 2003, 07:52 PM: Message edited by: mrcfitzgerald ]</small>

There are two reasons why normal people (including terrorists) can't build a nuke:
- they can't design it (no, it's not simple, not simple at all, whatever you may think)
if anyone want's to build one, he/she must at least have a universite degree in nuclear physics and access to several libraries to research the important variables (the cross-section for one. you may try to find it, it took me days)
- they can't build it. you simply need too advanced equipment and protection.

If you really want to build such a device, i would recommend electrically heating a Lithium-deuteride mixture to extreme temperatures and compress that.

Do you have evidence to back up that hypothesis?

As one who has access to the libraries for research, and most of the imporant variables (all gleaned from open literature of course) -I have come to believe that it is possible to design and build a 1 or 2 kiloton nuclear device. The matter is simple enough, any intelligent person can figure out all the variables required for a gun-type nuclear device. It is not really (the gun-type at least) that complex. Heck, I can even pull of efficiency formulas to tell me what the yield is given the number of critical masses.

The only difficult variable is the Uranium, and this is what limmits terrorists and "rogue" nations. Condsider the fact that, currently, there is several hundred tons of enriched uranium present in Russia alone. Of this, a terrorist only needs about 100lbs -likely less. Also consider the fact that we had a project in which newly graduated phyicist worked from scratch and designed a workable device. Note: they designed and implosion type because they figured that a guntype was too simple.

The end result is that it is somewhat possible... A feeling shared by many experts in the field. (Most importaint of which would be Carey Sublette and Richard Garwin).

Now as for electrical ignition of Fusion fuel....Well if that was possible, I think the military would be using it... I have looked at two related concepts, the Z-pinch and the MTF fusion schemes (as they are most easily adapted to weapons). The use of an FCG brings the concept close to break even, the problem is fusion fuel -got tritium? (the military only has about 4 kilograms total...) Anyway, the concept is not possible, except for the super-powers -and even then it is not worth the effort at that level.

Once you have enough bomb grade uranium or plutonium, making a bomb isnt rocket science. Making a high yeild bomb is difficult but getting a decent bang would not be hard, particulally from uranium.

Gun system was simple, but it wasnt compressing anything. The more you compress the smaller the critical mass is and if you can do this rapidly the higher the yeild is for a given amount of fissionable material. Implosion type puts the core under millions of atmospheres of pressure making its density at point of ignition much higher.

The U-235 crossection in unclassified books is usually for thermal neutrons, it isnt useful for designing a bomb. It is my understanding that the neutron cross section for fission neutrons is kept secret along with how it changes for different energies in the region.

You better be careful, Marvin. You might get a visit some night by ragheads that want you to come work on a project in their tent.

Making a bomb, is quite difficult. If your calculations aren't exact enough, your bomb will just fizzle. Don't take it that easy, really don't. You need at least a degree in nuclear physics, trust me. Did you think about igniting the fission, because if you don't have the exact mixture and mass, it won't start. What if your neutrons leave before fission takes place, a factor wich can easily be overseen. Or what if you create a too small nuclear explosion that will just throw out all of your fissionable material with a small bang. Now, thrust me, it ain't simple at all.

And for this electrical fusion i refer to US patent no 6,654,433. I personaly am sceptic about electrical fusion, like the Farnsworth Fusor and such.

"Making a bomb, is quite difficult. "

Getting the fuel is next to impossible. Making a bomb if you have enough is far more engineering than physics.

"You need at least a degree in nuclear physics"

I assume from this that you are in the process of getting a degree in physics. You will be dissapointed. There is very little in most physics degrees that relate to a nuclear bomb and none of it is essential in that form.

"if you don't have the exact mixture and mass, it won't start."
"What if your neutrons leave before fission takes place"

I'm sorry rancid, but these are the objections of someone almost clueless about bombs. Someone that doesnt know the physics well enough, but more importantly hasnt read the highly detailed information allready public on bombs. The history, the design, the materials and accurate descriptions of both little boy and fat man. You will learn more about making a weapon in a few hours of reading the carey sublette stuff than in the whole of a physics degree.

For reference the best objections I can think of would be bomb preignition, which is when the core ignites well before maximum critical mass is reached, and that this is made much worse if you have to use reactor grade plutonium, which is most likley the fuel someone would have to use. Also an implosive lens is highly advanced convensional explosives design, most likely needing someone skilled/experienced in detonics.

10fingers,
I think it more likley I'd be asked by the people that in the propaganda war took the blue pill.

Everyone seems to reject plutonium on the basis that an implosion system is too hard to design and build for all but the best educated and trained professionals. I think that a gun system would be perfectly adequate for a terrorist, if they could get plutonium.

Now, before you all get excited about this and tell me I have no idea, etc... This makes more sense than you might think. Do you recall why, exactly, plutonium "can't" be used in a gun system? It is, I believe, because the mass makes the transition from sub to super-critical too slowly. As the critical point is reached, the devices detonates 'prematurely', dispersing the mass and wasting almost all the energy. A terrorist, though, seeks, as the name implies, terror. He would be quite happy with a tiny fraction of a full yield.

Consider the immense power of even a small nuclear bomb - usually multi-kiloton. If one gets a 10th of a percent efficiency from the device (relative to a good design. Far lower still compared to the theoretical energy available.), it still has the power of several tons equivalent of TNT. Picture the immense effect of several tons of TNT detonated in a massive crowd -- panic, chaos, 100s of deaths. Add to that the radiation -- deadly. The remaining 99%+ of the plutonium being spread around the area to contaminate the survivors -- deadly.

Then consider the effect on the public. They see that a nuclear device has been detonated in their country, by some terrorist. The experts are on TV announcing that the yield was incredibly small for the amount of plutonium used. There is no weapon left to inspect, so they don't know it was supposed to be so low-yielding. It must have been a fluke -- maybe their design was faulty, maybe it was just a slight mistake in construction or quality control problem. Who knows where the next one will hit, and how many blocks of city will be destroyed when it doesn't fizzle?

Ok, sorry about the long story about it. Basically what I'm saying is that you can get *some* fission out of a gun-type plutonium weapon, and *any* fission will be enough for an impact in a terrorist weapon.

Reactor grade uranium (~10%) will work, but be "dirty" as hell, and weigh tons.

But in the back of a truck? ;)

to I am the black one: If I remember well, Am 242 AFAIR has critical mass of only about 12 g, but it is hell to make it so forget it. I hope I guessed right isotope of Am don't take it as sure. US wanted to use it as source for neutron bomb

This is second time that I find this story about boy scout reactor and it is geting better:)

I love this guy and I would like to shake his hand (wearing gloves of course:)), but I doubt he is with us anymore:(

He is still alive. At least untill recently, as I saw him in a TV documentary about his nuclear adventures.

It's a nice story, but he was probably as close to having a working reactor as you are to a space mission after discovering fire :)

One thing about what rancid matt says is true. You need extremely sophisticated equipment to build an atom bomb. First of all you need to machine the U-235 that is going to fit in side of your atom bomb. Your talking like a 500,000$ piece of machinary to be able to perform such a task.

It all depends on the size of the explosion that you want. If you don't need something that big, 'dirty' and not so complicated, you can make a good shot at it.
The explosive lens system is too complicated for home building, so one should try a gun type, probably with an implosion and Uranium hydride (deuteride is much better, but expensive$!).
A cylindrical rod is assebled of the UD3 (coated of course!) that slides into a cylinder that has a diameter of about 5 inches. Nextly, a track along which the core slides is put. it is slid at high speeds using a sort of gun or rocket and the end is plugged with beryllium. This UD3 assembly is than compressed explosively. It may have a beryllium tamper for more power

No, Uranium Hydride will not work in a nuclear device. The hydrogen moderates the neutrons, and causes them to travel slower. This has the effect of reducing the number of chain reactions before disassembly, and this leads to not only a higher critical mass -but a much lower efficiency. Uranium Hydride was used in two test, both of which fizzled with a yield of only 200 tons. The gov't scrapped the idea after that...

anarchy,

"The explosive lens system is too complicated for home building, "

This seems to be missing the point somewhat. If you have enough material for a gun type, thats what you make. If you have significantly less than 2 critical masses a gun type is going to do nothing impressive, and if you have plutonium it isnt going to work at all. Under those circumstances an implosive system is the only choice.


tom,

The first bombs didnt use expensive assembly machinery at all, it was all done by hand. Uranium can probably be worked on a metal lathe.

Actually, any radioactive compound can be used in a nuke, IF it is chain-fissionable. That means that it produces an average of 2 or more neutrons when it fissions. 92-235 works, as does 94-239. However, too high can cause pre detonations and fizzles (like 94-240). So, if you can get either 235 or 239, yes it is possible. All you need to do is make a mass of it larger than it's mean free path and kaboom!

malzraa,

I'm sorry but the two recent threads on this are allready beyond what you've posted. More interestingly, virtually everything you have written is wrong on a technicality. For radioactive compound you needed 'isotope', a compound has more than one element which isnt required, and nor is it required that the isotope be radioactive, though all known examples are I think. Producing 2 or more neutrons per fission avarage would get you a chain reaction in a big enough setting, but think, why 2? Wouldnt 1.5 be enough? 1.1? 1.000001? Secondly this is not the only requirement for a chain reaction, U-238 produces lots of neutrons when it fissions, and it can be fissioned by neutrons, but it cannot self sustain. See if you can figure out why.

Its background neutron flux that causes predetonations, nothing to do with the chain branching. I can see what you are trying to say by the mean free path, and you mean the path between fissions rather than scattering. This would I think be roughly valid for an avarage neutron production of 2, but for high branching you need less fissions to maintain and vice versa.

As an aside its theoretically possible for a compound to chain react where the isotopes individually would not. I can think of of a few theoretical systems, non would actually work because of lousy nuclear stats. I'd be interested in hearing any suggestions, purely for the purpose of broadening the thinking in this thread.

Clasically >1 critical mass, obtained either by slamming 2 masses together, or by compressing a non critical mass (Any amount of fissile material can be >1 critical mass if compressed enough). In practice forming slightly more than one crical mass slowly gets you a criticality accident, but no bang. 2 is the minimum anyone should really aim for and it needs to be done correctly.

I think there is something of a gap between what is taught in schools and universities and what is on the net in detail about the bombs. Maybe this thread can be fleshed out a bit to cover this gap.

Lets say we are talking about a terrorist. Wouldnt they want to make it as dirty as possible, and while I am sure that explosive capacity is all well and good, I think J_DMiller had a very valid point. Its the idea of it happening that matter to people. I recall the government hushing up the japanese bombing us with the Hot-air ballons in WW2...
But yeah, if we had all the materials, I would say its not rocket science.
Slightly OT but how hard is rocket science anyways? Its never seemed so hard to me...

Lets say we are talking about a terrorist. Wouldnt they want to make it as dirty as possible, and while I am sure that explosive capacity is all well and good, I think J_DMiller had a very valid point.

I believe the terrorists shall not spend a few ten (hundred?) millions to create an inefficient bang. They may find more uses for the money spent on such an inefficient nuclear device. Assume that you are spending USD 20 millions (which I believe very optimistic estimate, the amount may rise abouve hundred millions) for building such a bomb. With this amount of money, you may recruit cadres, buy ammo and weapons for them and create several conventional explosive devices.

In addition, there is a serious retailiation risk, given the fact that US levelled out Afghanistan following 9/11 events. What if they used a nuke device. In that case, I believe, US government would leave a big crater covering entire Afghanistan.

Slightly OT but how hard is rocket science anyways? Its never seemed so hard to me...
I believe rocket science not very hard. But the precise navigation systems are really hard. But recently I heard from TV that Hezbollah of Lebanon constructed a mannless aircraft to take photos of Israeli targets. Regards.

On the politics side, It's really not the bang that matters, it's the word 'radioactive', and the inability to inhabit a nice portion of NYC for several years/decade (unless there is some cleanup technique that I am not familiar with, which is inherently possible). Fear of death, not death itself is the key.

Also tangentially, guidance systems are not particularly difficult. You require a $200 solid-state chip to detect acceleration in the 3 planes of space, a cheap microcontroler, some basic multivariate calc, and a wiring diagram.

To the point, I do not believe it would be difficult to construct a primative atomic device, given the amount of materiel on the theory avaliable. That's not to say that anyone could do it, but anyone with a good degree of intellegence could pull it off (and we wouldn't really know if they didn't...).

There are two reasons why normal people (including terrorists) can't build a nuke:
- they can't design it (no, it's not simple, not simple at all, whatever you may think)
if anyone want's to build one, he/she must at least have a universite degree in nuclear physics and access to several libraries to research the important variables (the cross-section for one. you may try to find it, it took me days)
- they can't build it. you simply need too advanced equipment and protection.

.

why design a nuke when you can just copy the design of the little boy bomb - all of the critical details for it are portty much public domain now.

the only thing that you couldnt easily replicate from the little boy design is the nuetron source, but thats no biggie - just use a highly accurete switch to trigger the gun that launches your slug of u235 towards it's target and set off a zetatron from an oil well exploration nuetron source at the proper time and BOOM!

I remember reading that a large volume of water will wash away most radioactivity... Is there any truth to this? It sounds reasonable enough.
Although it would require a LOT of water.

Water will wash off radioactive dust, IE; fallout. Warships have systems to hose down the decks in case of contamination. The water doesn't make the dust less radioactive of course, it just washes it away.

Silentnite, rocket science is quite tricky, you have to get your drag, mass and thrust just right, or else you get tumbling. Drag too high, it won't fly. Drag too low, it flies high, but probably tumbles and you have no control over it. Thrust center has to be in front of the drag. The CoG has to be between the two, for the entire flight.

Non-trivial, especially if throwing a copper lined warhead weighing several pounds. For something like a nuke, you are talking at least 20Kg, so you need a huge rocket engine.


As regards fallout, you can wash it away, but on something like a steel ship, it isn't too hard, as there is nothing to really hold on to things. On a tarmac road, where you will just be washing it into the fabric of the road, on grass, on mud, etc. it will stay for years. Places with growing grass and plants are worst, since the roots hold on to the radioactive isotopes, and everything stays nasty for a long time.
Further, washing a kilo of "nuke dust" into the Pacific isn't going to do that much once it is diluted. Washing down a road will put a lot of that into the sewers, onto the grass, and leave you with really nasty hotspots.

In the news today it was reported that 66lb of plutonium had been ‘lost’ at a nuclear processing plant here in the UK. (Enough the article said for 7 nuclear bombs - allthough it didn't say whether it was the right grade)

http://www.keralanext.com/news/indexread.asp?id=120681

It turned out that this loss was due to inaccuracies in the measuring equipment they used. However if someone who worked there had proper security clearance then they might be able to sneak some out and they would blame the loss on inaccuracies.

I just wanted to ask...
Do they put uranium in artillery rounds, it's just that I heard trom news, that some uranium was recovered in Ukrain and they said one could build a bad a-bomb with it, but could be used in artillery shots and ARMOR.
I was courius, what did they mean with ARMOR...

Uranium strengthens the steel if you add some. In WWII Alies were scarred to death that Hitler started a nuke bomb project when they recieved the information Germans digging lot of uranium ore. Germans acctually use uranium to strenghten their tank armor.

Nuclear Weapons FAQ (http://nuclearweaponarchive.org/Nwfaq/Nfaq0.html)- Enough said.

I just wanted to ask...
Do they put uranium in artillery rounds, it's just that I heard trom news, that some uranium was recovered in Ukrain and they said one could build a bad a-bomb with it, but could be used in artillery shots and ARMOR.
I was courius, what did they mean with ARMOR...

depleted uranium (U-238 left over after enrichment) is used in shells instead of lead that used to be used to make a bigger impact when the shell hits as it is rather heavy and i presume dense

I just wanted to ask...
Do they put uranium in artillery rounds, it's just that I heard trom news, that some uranium was recovered in Ukrain and they said one could build a bad a-bomb with it, but could be used in artillery shots and ARMOR.
I was courius, what did they mean with ARMOR...

depleted uranium (U-238 left over after enrichment) is used in shells instead of lead that used to be used to make a bigger impact when the shell hits as it is rather heavy and i presume dense

I just wanted to ask...
Do they put uranium in artillery rounds, it's just that I heard trom news, that some uranium was recovered in Ukrain and they said one could build a bad a-bomb with it, but could be used in artillery shots and ARMOR.
I was courius, what did they mean with ARMOR...

depleted uranium (U-238 left over after enrichment) is used in shells instead of lead that used to be used to make a bigger impact when the shell hits as it is rather heavy and i presume dense

Hrm, I guess the implosion device wouldn't even be that difficult. If the people are skilled enough to obtain the radioactive material, then they could likely whip up some composition 4, and create a sphere around the material of c4, enough of it to the point that the explosion force would be large enough to complete fusion. I'm picturing a guy with a good 40lbs of C4, to the point it won't much matter if it doesn't fuse, because of the huge radioactive crater thats left. As for obtaining the radioactive iso's, well, what about old russian equipment on the market?

Hrm, I guess the implosion device wouldn't even be that difficult. If the people are skilled enough to obtain the radioactive material, then they could likely whip up some composition 4, and create a sphere around the material of c4, enough of it to the point that the explosion force would be large enough to complete fusion. I'm picturing a guy with a good 40lbs of C4, to the point it won't much matter if it doesn't fuse, because of the huge radioactive crater thats left. As for obtaining the radioactive iso's, well, what about old russian equipment on the market?

Hrm, I guess the implosion device wouldn't even be that difficult. If the people are skilled enough to obtain the radioactive material, then they could likely whip up some composition 4, and create a sphere around the material of c4, enough of it to the point that the explosion force would be large enough to complete fusion. I'm picturing a guy with a good 40lbs of C4, to the point it won't much matter if it doesn't fuse, because of the huge radioactive crater thats left. As for obtaining the radioactive iso's, well, what about old russian equipment on the market?

Um... Not to offend you, Rocket-Boy, but I think that you do underestimate significantly the difficulty in constructing an implosion device. Just putting a sphere of C4 (or any other explosive) around the fissionable material is not going to work. Sorry if I'm underestimating you, but I can just picture a sphere being detonated at only one point and the explosive force squeezing the Pu or U out the other side before the detonation completes :):).

Side Note -- I have heard (though I don't recall where) that C4 and such are actually too flexible to hold the precise lens shapes required.

In any case, you need very accurately timed detonations right round the sphere. Also, you need to: a) shape the exposives very carefully b) have explosives of a very uniform VoD and c) use different types of explosive with different velocities. This is to make sure that the blast wave hits the material evenly to compress it into the right shape.

Consider also the task being performed-- you are collapsing a rather thick-walled hollow sphere made of a dense, tough metal. Remember that uranium was used in tank armour. That isn't easy, and it's best accomplished not by brute force, such as huge amounts of explosive, but by carefull use of shaped charges.

I don't know how much inaccuracy you can have and still have a partial detonation, as opposed to just a crappy nuclear reactor that melts itself apart in an instant. I believe it's not much, but probablya good bit more than the powers that be like to admit.

Criticality is something that people disregard. For some reason, people think that it's trivial to figure out when something will, and will not, be of critical mass. I'm not well versed in the physics/engineering of the problem, but I'd say that while it may be easy to figure out the critical mass of say, Pu-239, formed into a solid sphere, with no neutron reflectors. But, I'd say it's somewhat harder to calculate when it's a hollow shere of a (possibly unknown) mix of Pu-239 and -240, under the influence of a shockwave, surrounded by a neutron-reflecting tamper. It would suck, to say the least, to have miscalculated the critical mass badly enough that it went critical before detonation. And considering the limited compression abilities of the implosion system of a terrorist device, there isn't much room between a premature critical mass and a failure to generate a critical mass.

I've been very negative so far, but I'll balance all this with the fact that when the US intentionally mis-fired weapons, by only detonating part of the implosion system as a safety check, they still got a fission yield, as I recall. As I stated in my earlier post, ANY fission yield is enough to acheive the goals.

Oh yeah, and how about a terrorist [state] who buys a bunch of (non- or semi-enriched) uranium from whatever source and builds a non-sheilded reactor in downtown New York? Wouldn't that do the trick for him?

Um... Not to offend you, Rocket-Boy, but I think that you do underestimate significantly the difficulty in constructing an implosion device. Just putting a sphere of C4 (or any other explosive) around the fissionable material is not going to work. Sorry if I'm underestimating you, but I can just picture a sphere being detonated at only one point and the explosive force squeezing the Pu or U out the other side before the detonation completes :):).

Side Note -- I have heard (though I don't recall where) that C4 and such are actually too flexible to hold the precise lens shapes required.

In any case, you need very accurately timed detonations right round the sphere. Also, you need to: a) shape the exposives very carefully b) have explosives of a very uniform VoD and c) use different types of explosive with different velocities. This is to make sure that the blast wave hits the material evenly to compress it into the right shape.

Consider also the task being performed-- you are collapsing a rather thick-walled hollow sphere made of a dense, tough metal. Remember that uranium was used in tank armour. That isn't easy, and it's best accomplished not by brute force, such as huge amounts of explosive, but by carefull use of shaped charges.

I don't know how much inaccuracy you can have and still have a partial detonation, as opposed to just a crappy nuclear reactor that melts itself apart in an instant. I believe it's not much, but probablya good bit more than the powers that be like to admit.

Criticality is something that people disregard. For some reason, people think that it's trivial to figure out when something will, and will not, be of critical mass. I'm not well versed in the physics/engineering of the problem, but I'd say that while it may be easy to figure out the critical mass of say, Pu-239, formed into a solid sphere, with no neutron reflectors. But, I'd say it's somewhat harder to calculate when it's a hollow shere of a (possibly unknown) mix of Pu-239 and -240, under the influence of a shockwave, surrounded by a neutron-reflecting tamper. It would suck, to say the least, to have miscalculated the critical mass badly enough that it went critical before detonation. And considering the limited compression abilities of the implosion system of a terrorist device, there isn't much room between a premature critical mass and a failure to generate a critical mass.

I've been very negative so far, but I'll balance all this with the fact that when the US intentionally mis-fired weapons, by only detonating part of the implosion system as a safety check, they still got a fission yield, as I recall. As I stated in my earlier post, ANY fission yield is enough to acheive the goals.

Oh yeah, and how about a terrorist [state] who buys a bunch of (non- or semi-enriched) uranium from whatever source and builds a non-sheilded reactor in downtown New York? Wouldn't that do the trick for him?

Um... Not to offend you, Rocket-Boy, but I think that you do underestimate significantly the difficulty in constructing an implosion device. Just putting a sphere of C4 (or any other explosive) around the fissionable material is not going to work. Sorry if I'm underestimating you, but I can just picture a sphere being detonated at only one point and the explosive force squeezing the Pu or U out the other side before the detonation completes :):).

Side Note -- I have heard (though I don't recall where) that C4 and such are actually too flexible to hold the precise lens shapes required.

In any case, you need very accurately timed detonations right round the sphere. Also, you need to: a) shape the exposives very carefully b) have explosives of a very uniform VoD and c) use different types of explosive with different velocities. This is to make sure that the blast wave hits the material evenly to compress it into the right shape.

Consider also the task being performed-- you are collapsing a rather thick-walled hollow sphere made of a dense, tough metal. Remember that uranium was used in tank armour. That isn't easy, and it's best accomplished not by brute force, such as huge amounts of explosive, but by carefull use of shaped charges.

I don't know how much inaccuracy you can have and still have a partial detonation, as opposed to just a crappy nuclear reactor that melts itself apart in an instant. I believe it's not much, but probablya good bit more than the powers that be like to admit.

Criticality is something that people disregard. For some reason, people think that it's trivial to figure out when something will, and will not, be of critical mass. I'm not well versed in the physics/engineering of the problem, but I'd say that while it may be easy to figure out the critical mass of say, Pu-239, formed into a solid sphere, with no neutron reflectors. But, I'd say it's somewhat harder to calculate when it's a hollow shere of a (possibly unknown) mix of Pu-239 and -240, under the influence of a shockwave, surrounded by a neutron-reflecting tamper. It would suck, to say the least, to have miscalculated the critical mass badly enough that it went critical before detonation. And considering the limited compression abilities of the implosion system of a terrorist device, there isn't much room between a premature critical mass and a failure to generate a critical mass.

I've been very negative so far, but I'll balance all this with the fact that when the US intentionally mis-fired weapons, by only detonating part of the implosion system as a safety check, they still got a fission yield, as I recall. As I stated in my earlier post, ANY fission yield is enough to acheive the goals.

Oh yeah, and how about a terrorist [state] who buys a bunch of (non- or semi-enriched) uranium from whatever source and builds a non-sheilded reactor in downtown New York? Wouldn't that do the trick for him?

arggg... No an implosion device would certainly be an extrodinarily complex undertaking. Can you imagine using differing layers of explosive each with different VoDs to shape a spherical wave from a single point and bend it into inwards moving parabolic wave. (easier said than done because the transitions between high VoD explosive and low VoD explosive are not immediate and take some time.) Now imagine designing this lense system to cooperate with 96 indentical sets, Now imagine engineering each one accuratly enough (within 1mm) and pouring the explosives with enough consistancy that each imploading wave meshes with the next. Also, you would need to ensure that the detonators all go of at the same time -literally within 100 nanoseconds. Normal detonators are not good enough, you would need to use at least a slapper type. To say the least, ~1500 lbs of good explosive would be needed just for a nominal 20kt weapon. The list goes on and on... A spherical implosion system is just way, way to advanced for anyone other than nations to design from scratch. A cylindrical and planar implosion sysem, however, looks more "promising," in that 2 dimmensional and 1 dimmensional inward moving shockwaves are far more stable than 3 dimmensional inward moving shockwaves.

arggg... No an implosion device would certainly be an extrodinarily complex undertaking. Can you imagine using differing layers of explosive each with different VoDs to shape a spherical wave from a single point and bend it into inwards moving parabolic wave. (easier said than done because the transitions between high VoD explosive and low VoD explosive are not immediate and take some time.) Now imagine designing this lense system to cooperate with 96 indentical sets, Now imagine engineering each one accuratly enough (within 1mm) and pouring the explosives with enough consistancy that each imploading wave meshes with the next. Also, you would need to ensure that the detonators all go of at the same time -literally within 100 nanoseconds. Normal detonators are not good enough, you would need to use at least a slapper type. To say the least, ~1500 lbs of good explosive would be needed just for a nominal 20kt weapon. The list goes on and on... A spherical implosion system is just way, way to advanced for anyone other than nations to design from scratch. A cylindrical and planar implosion sysem, however, looks more "promising," in that 2 dimmensional and 1 dimmensional inward moving shockwaves are far more stable than 3 dimmensional inward moving shockwaves.

arggg... No an implosion device would certainly be an extrodinarily complex undertaking. Can you imagine using differing layers of explosive each with different VoDs to shape a spherical wave from a single point and bend it into inwards moving parabolic wave. (easier said than done because the transitions between high VoD explosive and low VoD explosive are not immediate and take some time.) Now imagine designing this lense system to cooperate with 96 indentical sets, Now imagine engineering each one accuratly enough (within 1mm) and pouring the explosives with enough consistancy that each imploading wave meshes with the next. Also, you would need to ensure that the detonators all go of at the same time -literally within 100 nanoseconds. Normal detonators are not good enough, you would need to use at least a slapper type. To say the least, ~1500 lbs of good explosive would be needed just for a nominal 20kt weapon. The list goes on and on... A spherical implosion system is just way, way to advanced for anyone other than nations to design from scratch. A cylindrical and planar implosion sysem, however, looks more "promising," in that 2 dimmensional and 1 dimmensional inward moving shockwaves are far more stable than 3 dimmensional inward moving shockwaves.

Using U-235 separated from natural uranium, would require either uranium ore and a LOT of equipment for purifying, enrichment and so on. The chemical behaviour of the two main isotopes differ very little, so one would have to rely of a cascade system of high-speed centrifuges, which would be exceedningly hard either to obtain or build. The same goes for the uranium ore, digging that up requires a lot of resources, and is almost impossible to do without anyone noticing. Plutonium on the other hand is a different element and therefore easier to separate chemically from the U-238 (once you have a breeder-reactor...) But the prescence of higher Pu-isotopes would still require some isotope separation.

U-233 generated from Th-232 in a breeder would be easier to separate, it could be done chemically since U is a different element. Perhaps chemically separated Uranium from the said type of reactor could be used directly in a nuclear weapon, but that of course depends of what other U-isotopes are formed, their percentage and properties. One thing that points in the direction of if being easier that separating Pu isotopes is that there are much fewer stable U-isotopes in the vicinity. U-232 is unstable, only U-234 would be a bitch since 235 is also fissible.

But even though these thoughs on isotope separation are just stupid thoughts from a layman, one thing remains true: Thorium ore should be much easier to aqurie than uranium. Less monitored, and ThO2 is one of the best refractories there is (hence its use in gas mantles), ThO2 melts at 3390 degrees centigrade, and is probably quite chemically resistant. These properies make for a legitimate use of the material, making it easier to aquire, "we´re only building a 3000 degree centrigrade oven to burn things to hell".

However, thorium requries activation since its a lot less fissile and a lot less active than even U-238, so to be able to use Th-232 in a breeder type reactor one would have to add lots and lots of neutrons until the U-233 ammount gets high enough for the reactor to self-sustain. If these neutrons would come from radioactive elements, we're back on the first page of "impossible to aquire". Buying fifty-million standard size alpha sources, fire alarms or buying all old Ra-glow clocks that has ever been made would seem quite... odd.

Only thing I could think of to generate enough neutrons for the reactor to self sustain ("in a lifetime, please...") would be to build a big ass neutron cannon, neutrons would have to be generated by other means than radioactive isotopes.

The old method of generating neutrons by shooting alpha-rays (AKA He-4 nucleus, from radioactive isotopes) into Beryllium gives a yield of about thirty (30) neutrons per million of alpha particles. Now try to imagine how much energy it would require to make a decent flux of neutrons, lacking that ammount of radioactive isotopes we'd have to make those alpha-particles ourselves and accelerate them to a few MeV's. Impossible of course, but still an interesting calculation in its absurdity how many milligrams a year of U-233 the whole energy consumption of the US would be able to make.

But, I've heard talks of a novel type of neutron generating device using high energy protons fired against a heavy-metal target. This is supposed to split the nucleus and generate lots of neutrons, up to eighy a hit. This kind of device has already been built, the ISIS neutron source in the Rutherford Appleton Laboratory in Oxfordshire is of this type. http://www.isis.rl.ac.uk/ is it's homepage. Apparently you can "buy" time there doing experiments with the unmatched neutron flux. "How much for 10 years of eeeh, radioing our.... heating mantles?" :D

This type of device should be vastly (millions of times, even) more efficent than the old typ of neutron cannons, it could provide a large enough neutron flux to kick our Th-232 breeder into operation, this without us having to aquire kilograms of (virtually inobtainable) radioactive isotopes. This skips most of the "inobtainable materials-problem", but of course one would have to plow down tens or hundreds of millions of dollars into research, a breeder reactor is not exatly a lever, let alone a linear accelerator. Separating large ammounts of highly radioactive materials chemically might be easier than building a gargantic centrifuge system, but its certainly not like making soda water from citric acid and bicarb....

EDIT: Speling.

Using U-235 separated from natural uranium, would require either uranium ore and a LOT of equipment for purifying, enrichment and so on. The chemical behaviour of the two main isotopes differ very little, so one would have to rely of a cascade system of high-speed centrifuges, which would be exceedningly hard either to obtain or build. The same goes for the uranium ore, digging that up requires a lot of resources, and is almost impossible to do without anyone noticing. Plutonium on the other hand is a different element and therefore easier to separate chemically from the U-238 (once you have a breeder-reactor...) But the prescence of higher Pu-isotopes would still require some isotope separation.

U-233 generated from Th-232 in a breeder would be easier to separate, it could be done chemically since U is a different element. Perhaps chemically separated Uranium from the said type of reactor could be used directly in a nuclear weapon, but that of course depends of what other U-isotopes are formed, their percentage and properties. One thing that points in the direction of if being easier that separating Pu isotopes is that there are much fewer stable U-isotopes in the vicinity. U-232 is unstable, only U-234 would be a bitch since 235 is also fissible.

But even though these thoughs on isotope separation are just stupid thoughts from a layman, one thing remains true: Thorium ore should be much easier to aqurie than uranium. Less monitored, and ThO2 is one of the best refractories there is (hence its use in gas mantles), ThO2 melts at 3390 degrees centigrade, and is probably quite chemically resistant. These properies make for a legitimate use of the material, making it easier to aquire, "we´re only building a 3000 degree centrigrade oven to burn things to hell".

However, thorium requries activation since its a lot less fissile and a lot less active than even U-238, so to be able to use Th-232 in a breeder type reactor one would have to add lots and lots of neutrons until the U-233 ammount gets high enough for the reactor to self-sustain. If these neutrons would come from radioactive elements, we're back on the first page of "impossible to aquire". Buying fifty-million standard size alpha sources, fire alarms or buying all old Ra-glow clocks that has ever been made would seem quite... odd.

Only thing I could think of to generate enough neutrons for the reactor to self sustain ("in a lifetime, please...") would be to build a big ass neutron cannon, neutrons would have to be generated by other means than radioactive isotopes.

The old method of generating neutrons by shooting alpha-rays (AKA He-4 nucleus, from radioactive isotopes) into Beryllium gives a yield of about thirty (30) neutrons per million of alpha particles. Now try to imagine how much energy it would require to make a decent flux of neutrons, lacking that ammount of radioactive isotopes we'd have to make those alpha-particles ourselves and accelerate them to a few MeV's. Impossible of course, but still an interesting calculation in its absurdity how many milligrams a year of U-233 the whole energy consumption of the US would be able to make.

But, I've heard talks of a novel type of neutron generating device using high energy protons fired against a heavy-metal target. This is supposed to split the nucleus and generate lots of neutrons, up to eighy a hit. This kind of device has already been built, the ISIS neutron source in the Rutherford Appleton Laboratory in Oxfordshire is of this type. http://www.isis.rl.ac.uk/ is it's homepage. Apparently you can "buy" time there doing experiments with the unmatched neutron flux. "How much for 10 years of eeeh, radioing our.... heating mantles?" :D

This type of device should be vastly (millions of times, even) more efficent than the old typ of neutron cannons, it could provide a large enough neutron flux to kick our Th-232 breeder into operation, this without us having to aquire kilograms of (virtually inobtainable) radioactive isotopes. This skips most of the "inobtainable materials-problem", but of course one would have to plow down tens or hundreds of millions of dollars into research, a breeder reactor is not exatly a lever, let alone a linear accelerator. Separating large ammounts of highly radioactive materials chemically might be easier than building a gargantic centrifuge system, but its certainly not like making soda water from citric acid and bicarb....

EDIT: Speling.

Using U-235 separated from natural uranium, would require either uranium ore and a LOT of equipment for purifying, enrichment and so on. The chemical behaviour of the two main isotopes differ very little, so one would have to rely of a cascade system of high-speed centrifuges, which would be exceedningly hard either to obtain or build. The same goes for the uranium ore, digging that up requires a lot of resources, and is almost impossible to do without anyone noticing. Plutonium on the other hand is a different element and therefore easier to separate chemically from the U-238 (once you have a breeder-reactor...) But the prescence of higher Pu-isotopes would still require some isotope separation.

U-233 generated from Th-232 in a breeder would be easier to separate, it could be done chemically since U is a different element. Perhaps chemically separated Uranium from the said type of reactor could be used directly in a nuclear weapon, but that of course depends of what other U-isotopes are formed, their percentage and properties. One thing that points in the direction of if being easier that separating Pu isotopes is that there are much fewer stable U-isotopes in the vicinity. U-232 is unstable, only U-234 would be a bitch since 235 is also fissible.

But even though these thoughs on isotope separation are just stupid thoughts from a layman, one thing remains true: Thorium ore should be much easier to aqurie than uranium. Less monitored, and ThO2 is one of the best refractories there is (hence its use in gas mantles), ThO2 melts at 3390 degrees centigrade, and is probably quite chemically resistant. These properies make for a legitimate use of the material, making it easier to aquire, "we´re only building a 3000 degree centrigrade oven to burn things to hell".

However, thorium requries activation since its a lot less fissile and a lot less active than even U-238, so to be able to use Th-232 in a breeder type reactor one would have to add lots and lots of neutrons until the U-233 ammount gets high enough for the reactor to self-sustain. If these neutrons would come from radioactive elements, we're back on the first page of "impossible to aquire". Buying fifty-million standard size alpha sources, fire alarms or buying all old Ra-glow clocks that has ever been made would seem quite... odd.

Only thing I could think of to generate enough neutrons for the reactor to self sustain ("in a lifetime, please...") would be to build a big ass neutron cannon, neutrons would have to be generated by other means than radioactive isotopes.

The old method of generating neutrons by shooting alpha-rays (AKA He-4 nucleus, from radioactive isotopes) into Beryllium gives a yield of about thirty (30) neutrons per million of alpha particles. Now try to imagine how much energy it would require to make a decent flux of neutrons, lacking that ammount of radioactive isotopes we'd have to make those alpha-particles ourselves and accelerate them to a few MeV's. Impossible of course, but still an interesting calculation in its absurdity how many milligrams a year of U-233 the whole energy consumption of the US would be able to make.

But, I've heard talks of a novel type of neutron generating device using high energy protons fired against a heavy-metal target. This is supposed to split the nucleus and generate lots of neutrons, up to eighy a hit. This kind of device has already been built, the ISIS neutron source in the Rutherford Appleton Laboratory in Oxfordshire is of this type. http://www.isis.rl.ac.uk/ is it's homepage. Apparently you can "buy" time there doing experiments with the unmatched neutron flux. "How much for 10 years of eeeh, radioing our.... heating mantles?" :D

This type of device should be vastly (millions of times, even) more efficent than the old typ of neutron cannons, it could provide a large enough neutron flux to kick our Th-232 breeder into operation, this without us having to aquire kilograms of (virtually inobtainable) radioactive isotopes. This skips most of the "inobtainable materials-problem", but of course one would have to plow down tens or hundreds of millions of dollars into research, a breeder reactor is not exatly a lever, let alone a linear accelerator. Separating large ammounts of highly radioactive materials chemically might be easier than building a gargantic centrifuge system, but its certainly not like making soda water from citric acid and bicarb....

EDIT: Speling.

This always happens, I post something good -then wham Ive got to log in and my entire post is worthless. Arggg. Well, I dont have to much time so Ill just sum up what I would have said. First, Proton Spallation is worthless, unless you have a 2 or 3kilometer long accelerator and a hoover dam to power the thing. Second, I believe a more realistic alternative to linear acceletors would be the homogenous nuclear reactor. This would be usefull because of several important, inherent reactor characteristics. Since a homogenous reactor utilizes liquid as the carrier for uranium sulfate, it brings the uranium atoms close enough to a moderator to achieve criticality easily. More specifically, if one was to use ~1 ton of heavy water, one would not need to go through the pains of enriching uranium -they could use ~300-600lbs of good old natural, unenriched uranium, This isnt to say that the reactor is easily made, 1 ton of heavy water is nearly immpossible to extract, its just a little more possible than a uranium diffusion plant. Also, since the reactor is completely liquid in nature, onsite extraction of plutonium is fully possible. The catch, of course, is that the reactor is limmited to about 20 megatwatt day power production which means only about 20 grams a day Pu-239 production. This is more than made up, however, by the fact that there is no need to handle fission wastes, as these could be kept in the solution only.

This always happens, I post something good -then wham Ive got to log in and my entire post is worthless. Arggg. Well, I dont have to much time so Ill just sum up what I would have said. First, Proton Spallation is worthless, unless you have a 2 or 3kilometer long accelerator and a hoover dam to power the thing. Second, I believe a more realistic alternative to linear acceletors would be the homogenous nuclear reactor. This would be usefull because of several important, inherent reactor characteristics. Since a homogenous reactor utilizes liquid as the carrier for uranium sulfate, it brings the uranium atoms close enough to a moderator to achieve criticality easily. More specifically, if one was to use ~1 ton of heavy water, one would not need to go through the pains of enriching uranium -they could use ~300-600lbs of good old natural, unenriched uranium, This isnt to say that the reactor is easily made, 1 ton of heavy water is nearly immpossible to extract, its just a little more possible than a uranium diffusion plant. Also, since the reactor is completely liquid in nature, onsite extraction of plutonium is fully possible. The catch, of course, is that the reactor is limmited to about 20 megatwatt day power production which means only about 20 grams a day Pu-239 production. This is more than made up, however, by the fact that there is no need to handle fission wastes, as these could be kept in the solution only.

This always happens, I post something good -then wham Ive got to log in and my entire post is worthless. Arggg. Well, I dont have to much time so Ill just sum up what I would have said. First, Proton Spallation is worthless, unless you have a 2 or 3kilometer long accelerator and a hoover dam to power the thing. Second, I believe a more realistic alternative to linear acceletors would be the homogenous nuclear reactor. This would be usefull because of several important, inherent reactor characteristics. Since a homogenous reactor utilizes liquid as the carrier for uranium sulfate, it brings the uranium atoms close enough to a moderator to achieve criticality easily. More specifically, if one was to use ~1 ton of heavy water, one would not need to go through the pains of enriching uranium -they could use ~300-600lbs of good old natural, unenriched uranium, This isnt to say that the reactor is easily made, 1 ton of heavy water is nearly immpossible to extract, its just a little more possible than a uranium diffusion plant. Also, since the reactor is completely liquid in nature, onsite extraction of plutonium is fully possible. The catch, of course, is that the reactor is limmited to about 20 megatwatt day power production which means only about 20 grams a day Pu-239 production. This is more than made up, however, by the fact that there is no need to handle fission wastes, as these could be kept in the solution only.

I disagree on that, a linear accelerator capable of producing a 1 Gev proton beam of reasonable "density" does not have to be that huge.

http://www.hep.lu.se/atlas/thesis/egede/thesis-node5.html heres a proposed particle accelerator-collider capable of giving the protons 7000 times the energy required for a reactor. The greatest techical problem is not the particle energy, the device does not have to be kilometres long. The hard thing is to get the ammount of protons requried, most linac designs are just capable of producing fewer protons with higher energies. It seems impossible to extract useful information about the ISIS device (how big, how much energy, how many protons...). Stupid pop-sci page...

Homogenous reactors seems interesting, but would the fission products really stay in solution? One would think elements as different as iodine and caesium would be hard to keep in one specific solution. The radioactive gasses (like xenon!) would be a bitch to handle, but not impossible. Perhap isoluble crap forming from the fission products is not that big of a problem, only if elements (fission products) with huge cross-section like Hf or so steals away too many neutrons there could be trouble.

Quite a bit of research would be required, but much less than "my" reactor would. To build a "secret" nuclear reactor using natural uranium (or Th!) one would have to own a powerplant and build a (still secret) heavy-water factory. There is some H2S-diffusion mumbo-jombo that make it's extraction easier than distilling 100 000 volumes of water (as in the old days), but it would still not be like making coffee.

Btw,why dont you type your post in wordpad, and then copy and paste it in.

I disagree on that, a linear accelerator capable of producing a 1 Gev proton beam of reasonable "density" does not have to be that huge.

http://www.hep.lu.se/atlas/thesis/egede/thesis-node5.html heres a proposed particle accelerator-collider capable of giving the protons 7000 times the energy required for a reactor. The greatest techical problem is not the particle energy, the device does not have to be kilometres long. The hard thing is to get the ammount of protons requried, most linac designs are just capable of producing fewer protons with higher energies. It seems impossible to extract useful information about the ISIS device (how big, how much energy, how many protons...). Stupid pop-sci page...

Homogenous reactors seems interesting, but would the fission products really stay in solution? One would think elements as different as iodine and caesium would be hard to keep in one specific solution. The radioactive gasses (like xenon!) would be a bitch to handle, but not impossible. Perhap isoluble crap forming from the fission products is not that big of a problem, only if elements (fission products) with huge cross-section like Hf or so steals away too many neutrons there could be trouble.

Quite a bit of research would be required, but much less than "my" reactor would. To build a "secret" nuclear reactor using natural uranium (or Th!) one would have to own a powerplant and build a (still secret) heavy-water factory. There is some H2S-diffusion mumbo-jombo that make it's extraction easier than distilling 100 000 volumes of water (as in the old days), but it would still not be like making coffee.

Btw,why dont you type your post in wordpad, and then copy and paste it in.

I disagree on that, a linear accelerator capable of producing a 1 Gev proton beam of reasonable "density" does not have to be that huge.

http://www.hep.lu.se/atlas/thesis/egede/thesis-node5.html heres a proposed particle accelerator-collider capable of giving the protons 7000 times the energy required for a reactor. The greatest techical problem is not the particle energy, the device does not have to be kilometres long. The hard thing is to get the ammount of protons requried, most linac designs are just capable of producing fewer protons with higher energies. It seems impossible to extract useful information about the ISIS device (how big, how much energy, how many protons...). Stupid pop-sci page...

Homogenous reactors seems interesting, but would the fission products really stay in solution? One would think elements as different as iodine and caesium would be hard to keep in one specific solution. The radioactive gasses (like xenon!) would be a bitch to handle, but not impossible. Perhap isoluble crap forming from the fission products is not that big of a problem, only if elements (fission products) with huge cross-section like Hf or so steals away too many neutrons there could be trouble.

Quite a bit of research would be required, but much less than "my" reactor would. To build a "secret" nuclear reactor using natural uranium (or Th!) one would have to own a powerplant and build a (still secret) heavy-water factory. There is some H2S-diffusion mumbo-jombo that make it's extraction easier than distilling 100 000 volumes of water (as in the old days), but it would still not be like making coffee.

Btw,why dont you type your post in wordpad, and then copy and paste it in.

My reasoning for discounting the linear accelerator method is the immense amount of energy and effort required to drive the thing in the first place: remember each proton must be accererated to one Gev in order to spallate a lead nucleus, each nucleus yields 80 neutrons. Simple math indicates that each neutron then has ~1.25 Mev. Now, in order to make just one gram of pu-239, one would need (1/239)*6.022E23 Neutrons, each with an energy of 1.25 Mev -this means that inorder to make just one gram of usefull plutonium, and ideal system would require 504 Megajoules, or very roughly the equivalent of 250 lbs or TNT. No, suppose one wanted to make a reasonable amount of plutonium per day, say enough to build a weapon in ~3.5 years, that would require four grams a day. The energy requirements of 2016 Megajoules every 24 hours is a surprisingly low 0.023 megawatt hour per hour (a total of 0.56 megawatt hours per day), adding this up over every day of 3.5 years the energy requirements reach a grand total of 715.4 megawatts, and one gigantic electricity bill :) . The fact is, even in the ideal system a great amount of energy is needed, it is nothing one could do in their back yard. Also, keep in mind that the above equations (hopefully) indicate an ideal system -one where every neutron is absorbed by every uranium nucleus. The non-ideal system is probably going to be at least 5 times less interms of performance. Finally, the building of the liniac is no small issue, one needs a very very large linac inorder to accelerate protons to that kind of energy, the reason is simple: the goal is not just to get protons moving at 1 Gev for spallation, the goal is to get enough of them moving at 1 Gev to cause enough spallation to be remotely usefull. I believe the gov't is opening up a liniac like the one I described, it is three kilometers long, supercooled, and needs quite a bit of energy -there hope is to make the 3 kilograms of tritium required for our nuclear arsenal each year...

Now an interesting concept would make use of cyclotrons instead of liniacs; since the cyclotron's beam is circular in nature, it takes up much less space than a liniac of equivalent power -they are also more complex, however. I believe there is one 1-Gev cyclotron in service: http://www.triumf.info/public/about/background.php
but the four thousand ton magnets look pretty disparaging to the inexperienced builder....

Homogenous reactor designs are convieniently found on USPTO's website. They are not extrodinarily complex, they can vary in size from a beach ball to that of a railroad car. Insoluable products do contaminate the reactor vessel, but they can be removed to... if one desires. Radioactive Xenon is, of course, insoluable and may be vented outside the reactor system (I suppose if your the ecologically minded type, you could just vent it to the outside enviroment -I imagine Homeland Security wouldnt mind either ;) ) As for heavy water, well thats a difficult proposition -one would need to process at least several hundred tons of normal water.... Heavy water is not strictly necessary: the reactor would go critical with only one kilogram of highly enriched uranium and normal water... The reactor, if operated under certain conditions, can opperate as a fast breeder (although it cant really be classified as such.) So it is possible to make more fissile material than is consumed by the reactor in this case. A small gain of ~1.2 per unit burned.

My reasoning for discounting the linear accelerator method is the immense amount of energy and effort required to drive the thing in the first place: remember each proton must be accererated to one Gev in order to spallate a lead nucleus, each nucleus yields 80 neutrons. Simple math indicates that each neutron then has ~1.25 Mev. Now, in order to make just one gram of pu-239, one would need (1/239)*6.022E23 Neutrons, each with an energy of 1.25 Mev -this means that inorder to make just one gram of usefull plutonium, and ideal system would require 504 Megajoules, or very roughly the equivalent of 250 lbs or TNT. No, suppose one wanted to make a reasonable amount of plutonium per day, say enough to build a weapon in ~3.5 years, that would require four grams a day. The energy requirements of 2016 Megajoules every 24 hours is a surprisingly low 0.023 megawatt hour per hour (a total of 0.56 megawatt hours per day), adding this up over every day of 3.5 years the energy requirements reach a grand total of 715.4 megawatts, and one gigantic electricity bill :) . The fact is, even in the ideal system a great amount of energy is needed, it is nothing one could do in their back yard. Also, keep in mind that the above equations (hopefully) indicate an ideal system -one where every neutron is absorbed by every uranium nucleus. The non-ideal system is probably going to be at least 5 times less interms of performance. Finally, the building of the liniac is no small issue, one needs a very very large linac inorder to accelerate protons to that kind of energy, the reason is simple: the goal is not just to get protons moving at 1 Gev for spallation, the goal is to get enough of them moving at 1 Gev to cause enough spallation to be remotely usefull. I believe the gov't is opening up a liniac like the one I described, it is three kilometers long, supercooled, and needs quite a bit of energy -there hope is to make the 3 kilograms of tritium required for our nuclear arsenal each year...

Now an interesting concept would make use of cyclotrons instead of liniacs; since the cyclotron's beam is circular in nature, it takes up much less space than a liniac of equivalent power -they are also more complex, however. I believe there is one 1-Gev cyclotron in service: http://www.triumf.info/public/about/background.php
but the four thousand ton magnets look pretty disparaging to the inexperienced builder....

Homogenous reactor designs are convieniently found on USPTO's website. They are not extrodinarily complex, they can vary in size from a beach ball to that of a railroad car. Insoluable products do contaminate the reactor vessel, but they can be removed to... if one desires. Radioactive Xenon is, of course, insoluable and may be vented outside the reactor system (I suppose if your the ecologically minded type, you could just vent it to the outside enviroment -I imagine Homeland Security wouldnt mind either ;) ) As for heavy water, well thats a difficult proposition -one would need to process at least several hundred tons of normal water.... Heavy water is not strictly necessary: the reactor would go critical with only one kilogram of highly enriched uranium and normal water... The reactor, if operated under certain conditions, can opperate as a fast breeder (although it cant really be classified as such.) So it is possible to make more fissile material than is consumed by the reactor in this case. A small gain of ~1.2 per unit burned.

My reasoning for discounting the linear accelerator method is the immense amount of energy and effort required to drive the thing in the first place: remember each proton must be accererated to one Gev in order to spallate a lead nucleus, each nucleus yields 80 neutrons. Simple math indicates that each neutron then has ~1.25 Mev. Now, in order to make just one gram of pu-239, one would need (1/239)*6.022E23 Neutrons, each with an energy of 1.25 Mev -this means that inorder to make just one gram of usefull plutonium, and ideal system would require 504 Megajoules, or very roughly the equivalent of 250 lbs or TNT. No, suppose one wanted to make a reasonable amount of plutonium per day, say enough to build a weapon in ~3.5 years, that would require four grams a day. The energy requirements of 2016 Megajoules every 24 hours is a surprisingly low 0.023 megawatt hour per hour (a total of 0.56 megawatt hours per day), adding this up over every day of 3.5 years the energy requirements reach a grand total of 715.4 megawatts, and one gigantic electricity bill :) . The fact is, even in the ideal system a great amount of energy is needed, it is nothing one could do in their back yard. Also, keep in mind that the above equations (hopefully) indicate an ideal system -one where every neutron is absorbed by every uranium nucleus. The non-ideal system is probably going to be at least 5 times less interms of performance. Finally, the building of the liniac is no small issue, one needs a very very large linac inorder to accelerate protons to that kind of energy, the reason is simple: the goal is not just to get protons moving at 1 Gev for spallation, the goal is to get enough of them moving at 1 Gev to cause enough spallation to be remotely usefull. I believe the gov't is opening up a liniac like the one I described, it is three kilometers long, supercooled, and needs quite a bit of energy -there hope is to make the 3 kilograms of tritium required for our nuclear arsenal each year...

Now an interesting concept would make use of cyclotrons instead of liniacs; since the cyclotron's beam is circular in nature, it takes up much less space than a liniac of equivalent power -they are also more complex, however. I believe there is one 1-Gev cyclotron in service: http://www.triumf.info/public/about/background.php
but the four thousand ton magnets look pretty disparaging to the inexperienced builder....

Homogenous reactor designs are convieniently found on USPTO's website. They are not extrodinarily complex, they can vary in size from a beach ball to that of a railroad car. Insoluable products do contaminate the reactor vessel, but they can be removed to... if one desires. Radioactive Xenon is, of course, insoluable and may be vented outside the reactor system (I suppose if your the ecologically minded type, you could just vent it to the outside enviroment -I imagine Homeland Security wouldnt mind either ;) ) As for heavy water, well thats a difficult proposition -one would need to process at least several hundred tons of normal water.... Heavy water is not strictly necessary: the reactor would go critical with only one kilogram of highly enriched uranium and normal water... The reactor, if operated under certain conditions, can opperate as a fast breeder (although it cant really be classified as such.) So it is possible to make more fissile material than is consumed by the reactor in this case. A small gain of ~1.2 per unit burned.

Maybe I'm making a very basic and embarassing mathematical error, but...

0.023 megawatt hours per hour is 23 kilowatt hours per hour, which is just under 31 horsepower.

Even if it's far from ideal, there are diesel generators available that will put out 20 times that, cheaper than running off the power grid too.

Keeping the generator fuelled for 3.5 years might get expensive though...

I was thinging that one of the mining companies around this country would be a perfect front for this kind of thing, as they run massive amounts of heavy diesel machinery 24 hours a day, using totally mind boggling amounts of fuel.

Actually, now that I think about it, it would be much easier just to steal electricity from the power grid, avoiding the massive bills. A leak of 23 kilowatt hours per hour isn't going to be noticed, as huge quantities of of power are lost as resistance in transmission anyway...

Maybe I'm making a very basic and embarassing mathematical error, but...

0.023 megawatt hours per hour is 23 kilowatt hours per hour, which is just under 31 horsepower.

Even if it's far from ideal, there are diesel generators available that will put out 20 times that, cheaper than running off the power grid too.

Keeping the generator fuelled for 3.5 years might get expensive though...

I was thinging that one of the mining companies around this country would be a perfect front for this kind of thing, as they run massive amounts of heavy diesel machinery 24 hours a day, using totally mind boggling amounts of fuel.

Actually, now that I think about it, it would be much easier just to steal electricity from the power grid, avoiding the massive bills. A leak of 23 kilowatt hours per hour isn't going to be noticed, as huge quantities of of power are lost as resistance in transmission anyway...

Maybe I'm making a very basic and embarassing mathematical error, but...

0.023 megawatt hours per hour is 23 kilowatt hours per hour, which is just under 31 horsepower.

Even if it's far from ideal, there are diesel generators available that will put out 20 times that, cheaper than running off the power grid too.

Keeping the generator fuelled for 3.5 years might get expensive though...

I was thinging that one of the mining companies around this country would be a perfect front for this kind of thing, as they run massive amounts of heavy diesel machinery 24 hours a day, using totally mind boggling amounts of fuel.

Actually, now that I think about it, it would be much easier just to steal electricity from the power grid, avoiding the massive bills. A leak of 23 kilowatt hours per hour isn't going to be noticed, as huge quantities of of power are lost as resistance in transmission anyway...

As far as I know Thorium reactor is not self-sustainable. You have to use it with a neutron source.

So you have to have a working nuclear reactor at hand to breed U-233 out of thorium (or alternatively, as stated above, a huge accelerator producing massive flux of neutrons).

(Maybe this idea sucks but) What about having a really massive natural uranium reactor (or mass) to have neutrons needed?

As far as I know Thorium reactor is not self-sustainable. You have to use it with a neutron source.

So you have to have a working nuclear reactor at hand to breed U-233 out of thorium (or alternatively, as stated above, a huge accelerator producing massive flux of neutrons).

(Maybe this idea sucks but) What about having a really massive natural uranium reactor (or mass) to have neutrons needed?

As far as I know Thorium reactor is not self-sustainable. You have to use it with a neutron source.

So you have to have a working nuclear reactor at hand to breed U-233 out of thorium (or alternatively, as stated above, a huge accelerator producing massive flux of neutrons).

(Maybe this idea sucks but) What about having a really massive natural uranium reactor (or mass) to have neutrons needed?

It would actually be better to avoid the Thorium cycle and stick with good old Pu-239. This is because, U-233 has a greater critical mass (around 16Kg, a good reflector could make this 10Kg). Thus, using thorium as the neutron acceptor would require a little more than twice the time required for Pu-239. Also, I am afraid that my estimates are way, way to liberal. Recall, that the liniac was assumed to be an ideal system. In a real liniac, one would have to factor in cooling, downtime for parts replacement, and worst of all -the inefficiency of the liniac acceleration system. Remember, the idea system required 0.023 megawatts per hour -I assumed that every megatwatt put in was transfered 100% to the beam. This is not the case. Non-supercooled linaics only have an efficiency ~1%. That is to say, for every 100 megawatts put in, the actual total energy of the particle beam is 1 megawatt. This means, in our example, a liniac would, in practice, require not 0.023 Megawatts per hour for 3.5 years - but 2.3 Megawatts per hour for 3.5 years. The grand total is no longer the idealistic 715.4 Megawatts, but a much,much larger 71.54 Gigawatts. The energy costs are no longer $85,000, but $8.5 million. As you can see, a linaic is very difficult to use in conjunction with nuclear fuel.

The reason homogeneous reactors looked so usefull was because they were just so convienient in comparison to other -much more technologically demanding systems. Homogenous reactor systems cannot melt down. They are self-limmiting in nature (because waters moderating abilities decrease as temperature increases). They are about as simple as any reactor could ever be. Infact small (~2 megawatt) reactors were built at Los Alamos by individuals (I believe Richard Feyman). The moderating environment with the fuel interspersed is about as close to ideal as possible -and controlling the thing can be accomplished with a single boron neutron absorber. (Here is a good, basic introduction: http://home.earthlink.net/~bhoglund/hRE.html ) Also, the homogeneous reactor is the only complete reactor system I have ever seen in full detail at USPTO. Usually, the patent office is filled with billions of subsystems, safe guards, ext... Homogeneous reactors are the only kind simple enough to be fully described in Patent Literature. Even dimmensions of the system and enrichment are indicated...

As for natural uranium, it will work when used in conjunction with graphite or with heavy water. Graphite is most notable for its use in the early reactor types. It is not good, however, in that it requires ~80 tons of natural uranium and ~250 tons of graphite to go critical. (I believe Enrico Fermi's original patent is still available, and probably indicates the lower limmit of graphite reactor design) With homogenous reactors, however, enrichment is not necessary with heavy water. If enrichment is used, however, then only very small amounts of heu (1 kilogram) is required instead of the 80 tons for a solid reactor type.

It would actually be better to avoid the Thorium cycle and stick with good old Pu-239. This is because, U-233 has a greater critical mass (around 16Kg, a good reflector could make this 10Kg). Thus, using thorium as the neutron acceptor would require a little more than twice the time required for Pu-239. Also, I am afraid that my estimates are way, way to liberal. Recall, that the liniac was assumed to be an ideal system. In a real liniac, one would have to factor in cooling, downtime for parts replacement, and worst of all -the inefficiency of the liniac acceleration system. Remember, the idea system required 0.023 megawatts per hour -I assumed that every megatwatt put in was transfered 100% to the beam. This is not the case. Non-supercooled linaics only have an efficiency ~1%. That is to say, for every 100 megawatts put in, the actual total energy of the particle beam is 1 megawatt. This means, in our example, a liniac would, in practice, require not 0.023 Megawatts per hour for 3.5 years - but 2.3 Megawatts per hour for 3.5 years. The grand total is no longer the idealistic 715.4 Megawatts, but a much,much larger 71.54 Gigawatts. The energy costs are no longer $85,000, but $8.5 million. As you can see, a linaic is very difficult to use in conjunction with nuclear fuel.

The reason homogeneous reactors looked so usefull was because they were just so convienient in comparison to other -much more technologically demanding systems. Homogenous reactor systems cannot melt down. They are self-limmiting in nature (because waters moderating abilities decrease as temperature increases). They are about as simple as any reactor could ever be. Infact small (~2 megawatt) reactors were built at Los Alamos by individuals (I believe Richard Feyman). The moderating environment with the fuel interspersed is about as close to ideal as possible -and controlling the thing can be accomplished with a single boron neutron absorber. (Here is a good, basic introduction: http://home.earthlink.net/~bhoglund/hRE.html ) Also, the homogeneous reactor is the only complete reactor system I have ever seen in full detail at USPTO. Usually, the patent office is filled with billions of subsystems, safe guards, ext... Homogeneous reactors are the only kind simple enough to be fully described in Patent Literature. Even dimmensions of the system and enrichment are indicated...

As for natural uranium, it will work when used in conjunction with graphite or with heavy water. Graphite is most notable for its use in the early reactor types. It is not good, however, in that it requires ~80 tons of natural uranium and ~250 tons of graphite to go critical. (I believe Enrico Fermi's original patent is still available, and probably indicates the lower limmit of graphite reactor design) With homogenous reactors, however, enrichment is not necessary with heavy water. If enrichment is used, however, then only very small amounts of heu (1 kilogram) is required instead of the 80 tons for a solid reactor type.

It would actually be better to avoid the Thorium cycle and stick with good old Pu-239. This is because, U-233 has a greater critical mass (around 16Kg, a good reflector could make this 10Kg). Thus, using thorium as the neutron acceptor would require a little more than twice the time required for Pu-239. Also, I am afraid that my estimates are way, way to liberal. Recall, that the liniac was assumed to be an ideal system. In a real liniac, one would have to factor in cooling, downtime for parts replacement, and worst of all -the inefficiency of the liniac acceleration system. Remember, the idea system required 0.023 megawatts per hour -I assumed that every megatwatt put in was transfered 100% to the beam. This is not the case. Non-supercooled linaics only have an efficiency ~1%. That is to say, for every 100 megawatts put in, the actual total energy of the particle beam is 1 megawatt. This means, in our example, a liniac would, in practice, require not 0.023 Megawatts per hour for 3.5 years - but 2.3 Megawatts per hour for 3.5 years. The grand total is no longer the idealistic 715.4 Megawatts, but a much,much larger 71.54 Gigawatts. The energy costs are no longer $85,000, but $8.5 million. As you can see, a linaic is very difficult to use in conjunction with nuclear fuel.

The reason homogeneous reactors looked so usefull was because they were just so convienient in comparison to other -much more technologically demanding systems. Homogenous reactor systems cannot melt down. They are self-limmiting in nature (because waters moderating abilities decrease as temperature increases). They are about as simple as any reactor could ever be. Infact small (~2 megawatt) reactors were built at Los Alamos by individuals (I believe Richard Feyman). The moderating environment with the fuel interspersed is about as close to ideal as possible -and controlling the thing can be accomplished with a single boron neutron absorber. (Here is a good, basic introduction: http://home.earthlink.net/~bhoglund/hRE.html ) Also, the homogeneous reactor is the only complete reactor system I have ever seen in full detail at USPTO. Usually, the patent office is filled with billions of subsystems, safe guards, ext... Homogeneous reactors are the only kind simple enough to be fully described in Patent Literature. Even dimmensions of the system and enrichment are indicated...

As for natural uranium, it will work when used in conjunction with graphite or with heavy water. Graphite is most notable for its use in the early reactor types. It is not good, however, in that it requires ~80 tons of natural uranium and ~250 tons of graphite to go critical. (I believe Enrico Fermi's original patent is still available, and probably indicates the lower limmit of graphite reactor design) With homogenous reactors, however, enrichment is not necessary with heavy water. If enrichment is used, however, then only very small amounts of heu (1 kilogram) is required instead of the 80 tons for a solid reactor type.

Also, the homogeneous reactor is the only complete reactor system I have ever seen in full detail at USPTO. Usually, the patent office is filled with billions of subsystems, safe guards, ext... Homogeneous reactors are the only kind simple enough to be fully described in Patent Literature. Even dimmensions of the system and enrichment are indicated...



Any patent numbers or search criteria (keywords)? I searched it but failed to find them.

Also, the homogeneous reactor is the only complete reactor system I have ever seen in full detail at USPTO. Usually, the patent office is filled with billions of subsystems, safe guards, ext... Homogeneous reactors are the only kind simple enough to be fully described in Patent Literature. Even dimmensions of the system and enrichment are indicated...



Any patent numbers or search criteria (keywords)? I searched it but failed to find them.

Also, the homogeneous reactor is the only complete reactor system I have ever seen in full detail at USPTO. Usually, the patent office is filled with billions of subsystems, safe guards, ext... Homogeneous reactors are the only kind simple enough to be fully described in Patent Literature. Even dimmensions of the system and enrichment are indicated...



Any patent numbers or search criteria (keywords)? I searched it but failed to find them.

All the patents are before the 1976 cut-off so you cant search for them in the standard fashion, instead you must perform an advance search for the term ccl/976/dig31 and ccl/376/421 and make sure to select patents before 1976. These two searches should give you a list of almost all the homogenous reactor systems ever patented.

All the patents are before the 1976 cut-off so you cant search for them in the standard fashion, instead you must perform an advance search for the term ccl/976/dig31 and ccl/376/421 and make sure to select patents before 1976. These two searches should give you a list of almost all the homogenous reactor systems ever patented.

All the patents are before the 1976 cut-off so you cant search for them in the standard fashion, instead you must perform an advance search for the term ccl/976/dig31 and ccl/376/421 and make sure to select patents before 1976. These two searches should give you a list of almost all the homogenous reactor systems ever patented.

Dear Mr. Fitzgerald,
I don't make this post to challenge what you said but what you remarked in your previous posts caused me to investigate that why, if homogeneous reactors are so safe and easy to control, they are not used extensively (i.e. out of research laboratories) for power generation. And the very link you gave, answered my question marks.

I believe they have serious corrosion and precipitation problems which renders them to be prohibitive for use in a continuous and prolonged manner. But some designs may overcome these problems.

Anyway, I would chose Thorium cycle for the following reasons :
1) E-x-traction of Pu from the fuel shall be a pain in the as* since the exact procedure is not known very well (the same those skilled in the arts shit comes into action here :mad: ). I could not even find the patents for the e-x-traction process (though this might be due to my poor patent searching skills :( ).

2) In addition to above mentioned design bottlenecks / challenges you referred to above, I believe an implosion type device also need a good and powerful neutron generator which is again hard to design and synchronize with the detonation of conventional explosives.

3) Since U-233 is very similar to U-235 and can easily be obtained from thorium in abundant quantities, I believe a gun type device may be constructed without difficulty since it's simple and (I assume) does not require a neutron generator. (I assume this since U-233 acts very similar to U-235 and its detonation behaviour must be the same).

And back to homogeneous reactors, the links you gave again proposes that one has to have at least LEU at hand to have this setup to go critical. It also mentions about non-enriched uranium (with heavy water) but it does not give any quantities (other than having a pound of fissile material needed in general for all fuel types) and if the quantities you have mentioned for natural uranium graphite reactors are involved for this setup it's again a major drawback.

So in short this approach is again a dead end since you have to have enriched uranium at hand in order to have a working reactor. For that reason I believe it's beyond an individual enthuisast's capabilities.

Dear Mr. Fitzgerald,
I don't make this post to challenge what you said but what you remarked in your previous posts caused me to investigate that why, if homogeneous reactors are so safe and easy to control, they are not used extensively (i.e. out of research laboratories) for power generation. And the very link you gave, answered my question marks.

I believe they have serious corrosion and precipitation problems which renders them to be prohibitive for use in a continuous and prolonged manner. But some designs may overcome these problems.

Anyway, I would chose Thorium cycle for the following reasons :
1) E-x-traction of Pu from the fuel shall be a pain in the as* since the exact procedure is not known very well (the same those skilled in the arts shit comes into action here :mad: ). I could not even find the patents for the e-x-traction process (though this might be due to my poor patent searching skills :( ).

2) In addition to above mentioned design bottlenecks / challenges you referred to above, I believe an implosion type device also need a good and powerful neutron generator which is again hard to design and synchronize with the detonation of conventional explosives.

3) Since U-233 is very similar to U-235 and can easily be obtained from thorium in abundant quantities, I believe a gun type device may be constructed without difficulty since it's simple and (I assume) does not require a neutron generator. (I assume this since U-233 acts very similar to U-235 and its detonation behaviour must be the same).

And back to homogeneous reactors, the links you gave again proposes that one has to have at least LEU at hand to have this setup to go critical. It also mentions about non-enriched uranium (with heavy water) but it does not give any quantities (other than having a pound of fissile material needed in general for all fuel types) and if the quantities you have mentioned for natural uranium graphite reactors are involved for this setup it's again a major drawback.

So in short this approach is again a dead end since you have to have enriched uranium at hand in order to have a working reactor. For that reason I believe it's beyond an individual enthuisast's capabilities.

Dear Mr. Fitzgerald,
I don't make this post to challenge what you said but what you remarked in your previous posts caused me to investigate that why, if homogeneous reactors are so safe and easy to control, they are not used extensively (i.e. out of research laboratories) for power generation. And the very link you gave, answered my question marks.

I believe they have serious corrosion and precipitation problems which renders them to be prohibitive for use in a continuous and prolonged manner. But some designs may overcome these problems.

Anyway, I would chose Thorium cycle for the following reasons :
1) E-x-traction of Pu from the fuel shall be a pain in the as* since the exact procedure is not known very well (the same those skilled in the arts shit comes into action here :mad: ). I could not even find the patents for the e-x-traction process (though this might be due to my poor patent searching skills :( ).

2) In addition to above mentioned design bottlenecks / challenges you referred to above, I believe an implosion type device also need a good and powerful neutron generator which is again hard to design and synchronize with the detonation of conventional explosives.

3) Since U-233 is very similar to U-235 and can easily be obtained from thorium in abundant quantities, I believe a gun type device may be constructed without difficulty since it's simple and (I assume) does not require a neutron generator. (I assume this since U-233 acts very similar to U-235 and its detonation behaviour must be the same).

And back to homogeneous reactors, the links you gave again proposes that one has to have at least LEU at hand to have this setup to go critical. It also mentions about non-enriched uranium (with heavy water) but it does not give any quantities (other than having a pound of fissile material needed in general for all fuel types) and if the quantities you have mentioned for natural uranium graphite reactors are involved for this setup it's again a major drawback.

So in short this approach is again a dead end since you have to have enriched uranium at hand in order to have a working reactor. For that reason I believe it's beyond an individual enthuisast's capabilities.

U-233 is abundant, yes, but also a high-energy gamma emitter, making it's handling extremely dangerous compared to the U-235 isotope.

So either you have an endless supply of expendable workers ('cause they'll die after a few hours exposure), or a very expensive remote handling WALDO system.

U-233 is abundant, yes, but also a high-energy gamma emitter, making it's handling extremely dangerous compared to the U-235 isotope.

So either you have an endless supply of expendable workers ('cause they'll die after a few hours exposure), or a very expensive remote handling WALDO system.

U-233 is abundant, yes, but also a high-energy gamma emitter, making it's handling extremely dangerous compared to the U-235 isotope.


Sir,
Actually it's not U-233 which emits intense gamma rays but its contaminants namely U-232, decendants of which Bismuth 212 and thalium 208 that irradiate gamma rays. The U-233 transformation cycle involves emitting of gamma radiation though.

(Source (http://www.francenuc.org/en_mat/uranium3_e.htm))
But again I was trying to emphasize this approach (that is to say homogeneous reactor approach) is somewhat dead end, since unless you have some LEU you may not have this setup go critical.

The links Mr. Fitzgerald gave also mentions about natural uranium plus heavy water but no quantities are given. Even if we assume the quantities given in the original text (i.e. a pound of fissile material) is valid, I don't know an efficient (more importantly detailed) method to produce large quantities of heavy water in a cost effective manner.

Regarding the homogeneous reactors I found the following PDF (http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.ns.06.120156.001533) which gives some information about them.

P.S. Mr.Fitzgerald might be wrong about one thing, i.e. critical size of U-233. According to the source link I gave above, one kg U-233 is enough for making a kiloton sized device.

U-233 is abundant, yes, but also a high-energy gamma emitter, making it's handling extremely dangerous compared to the U-235 isotope.


Sir,
Actually it's not U-233 which emits intense gamma rays but its contaminants namely U-232, decendants of which Bismuth 212 and thalium 208 that irradiate gamma rays. The U-233 transformation cycle involves emitting of gamma radiation though.

(Source (http://www.francenuc.org/en_mat/uranium3_e.htm))
But again I was trying to emphasize this approach (that is to say homogeneous reactor approach) is somewhat dead end, since unless you have some LEU you may not have this setup go critical.

The links Mr. Fitzgerald gave also mentions about natural uranium plus heavy water but no quantities are given. Even if we assume the quantities given in the original text (i.e. a pound of fissile material) is valid, I don't know an efficient (more importantly detailed) method to produce large quantities of heavy water in a cost effective manner.

Regarding the homogeneous reactors I found the following PDF (http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.ns.06.120156.001533) which gives some information about them.

P.S. Mr.Fitzgerald might be wrong about one thing, i.e. critical size of U-233. According to the source link I gave above, one kg U-233 is enough for making a kiloton sized device.

Yes, the homogeneous reactors have corrosion issues and yes it is still very complex. The fact remains that they are the least complex of the reactor designs. For all their complexity, they are vastly easier to construct compared to modern, or even early solid-state reactors. Such a route, I feel, is less complex then something like a linac. (However impractical a home built reactor may be, it is far less than particle acceleration systems.) Also, homogeneous reactors are not used for power production because they are not sufficiently power-dense/power efficient. Generally, the higher the temperature in a reactor system, the better it can produce energy. Since homogeneous reactors are water based, that is they use water as the moderator, they can only run so hot before water ceases to be an effective moderator... Im not saying that its within any single individual's reach, just that it is closer.

Also, it seems U-233 is not a harmfull gamma emitter in itself, what is dangerous is U-232 which is formed when Thorium-230 catches a neutron: http://www.nuclearweaponarchive.org/Nwfaq/Nfaq6.html . So, if one were able to remove the trace thorium 230 contamination, one could also produce pure U-233 (given a neutron source)

Yes, the homogeneous reactors have corrosion issues and yes it is still very complex. The fact remains that they are the least complex of the reactor designs. For all their complexity, they are vastly easier to construct compared to modern, or even early solid-state reactors. Such a route, I feel, is less complex then something like a linac. (However impractical a home built reactor may be, it is far less than particle acceleration systems.) Also, homogeneous reactors are not used for power production because they are not sufficiently power-dense/power efficient. Generally, the higher the temperature in a reactor system, the better it can produce energy. Since homogeneous reactors are water based, that is they use water as the moderator, they can only run so hot before water ceases to be an effective moderator... Im not saying that its within any single individual's reach, just that it is closer.

Also, it seems U-233 is not a harmfull gamma emitter in itself, what is dangerous is U-232 which is formed when Thorium-230 catches a neutron: http://www.nuclearweaponarchive.org/Nwfaq/Nfaq6.html . So, if one were able to remove the trace thorium 230 contamination, one could also produce pure U-233 (given a neutron source)

Since I noticed my lack of knowledge in some aspects of nuclear devices, I searched the net about them (thanks to a few days of free time).

First of all I must admit that I have exaggerated the Pu e-*traction from the spent fuel. Actually there are myriads of info on the net regarding e-x*raction. And what I liked much is a site which states that in order to have Pu with low content of even numbered isotopes, one has to cook the fuel at the lower temperatures, a feature which commercial reactors lack. The commercial reactors work at elevated temperatures to be power efficient.

So Water Boiler Reactors might be ideal for this task, since they operate at relatively low temperatures provided that their corrosion problems are solved.

Regarding the extra*tion the only method I found most exiting and promising is supercritical fluid *xtraction. This process eliminates the need for massive amounts of nitric acid solutions to dissolve and extract Pu from the spent fuel.

In addition it only uses a supercritical fluid, which is actually liquid and compressed CO2 heated to (kept at) 35 degree celcius and forming an adduct with tributyril phosphate, (in kerosene, hexane or dodecene) plus nitric acid. When you apply this supercritical fluid complex to (thermally) pulverized spent fuel, the lantanides (sp?) are dissolved in the fluid and when you remove the pressure from the reaction vessel, CO2 evaporates and you simply have a solution containing U and Pu. Very neat and elegant and most importantly not bulky :). But I must confess that I could not understand how mixture of U and Pu is separated by using redox :eek: .

Anyway here are some links, read yourself :
http://www.cea.fr/gb/publications/Clefs46/pagesg/clefs46_10.html
http://www.ieer.org/sdafiles/vol_5/5-1/purexch.html
http://www.euronuclear.org/info/encyclopedia/p/purex-process.htm
http://www.hindu.com/thehindu/seta/2003/08/21/stories/2003082100060200.htm (Supercritical fluid (i.e. CO2))
http://www.ricin.com/nuke/bg/lahague.html
http://216.239.59.104/search?q=cache:SpuWouhIUkIJ:www.francenuc.org/en_chn/irr_fuel1_e.htm+PUREX+%2BUranium&hl=tr
http://home.austarnet.com.au/davekimble/peakuranium.htm
http://tauon.nuc.berkeley.edu/asia/1999/TPE99Enokida.pdf (Supercritical fluid (i.e. CO2) detailed process)

But the major disappointment I had is Heavy Water processes. The one which looks most promising (i.e. Girdler Sulfide process) (with respect to energy consumption) requires very high colums (more than 90 m high) with several sieves which are hard to hide. Now I am looking for a simple process to have (say a few liters of) heavy water. Anybody know such a process? Maybe process is over there but I somehow missed it.

The processes I found are as follows :

http://www.fas.org/nuke/intro/nuke/heavy.htm (Heavy Water)
http://www.fas.org/irp/threat/mctl98-2/p2sec05.pdf (Heavy Water)
http://www.iraqwatch.org/government/US/DOE/DOE-CHAPTER5.PDF (Heavy Water, some data about the sizes of Heavy Water production (enrichment) facilities)

An interesting neutron generator link :

http://www.lbl.gov/Science-Articles/Archive/neutronGenerator.html

In addition there is an article which I cannot reach. Anybody with a university subscription may have it easily and free of charge. This article is the very article where SCF (supercritical fluid) process is described. So college students (I know there are many amongst us, and majority of them are technical university students I believe) may get this article for the benefit of the forum.

Anyway here it is :
Reference article: O. Tomioka, Y. Enokida, I. Yamamoto, ÒSolvent Extraction of Lanthanides from Their Oxides
with TBP in Supercritical CO2,Ó Journal of Nuclear Science and Technology, 35, 515 (1998).

Since I noticed my lack of knowledge in some aspects of nuclear devices, I searched the net about them (thanks to a few days of free time).

First of all I must admit that I have exaggerated the Pu e-*traction from the spent fuel. Actually there are myriads of info on the net regarding e-x*raction. And what I liked much is a site which states that in order to have Pu with low content of even numbered isotopes, one has to cook the fuel at the lower temperatures, a feature which commercial reactors lack. The commercial reactors work at elevated temperatures to be power efficient.

So Water Boiler Reactors might be ideal for this task, since they operate at relatively low temperatures provided that their corrosion problems are solved.

Regarding the extra*tion the only method I found most exiting and promising is supercritical fluid *xtraction. This process eliminates the need for massive amounts of nitric acid solutions to dissolve and extract Pu from the spent fuel.

In addition it only uses a supercritical fluid, which is actually liquid and compressed CO2 heated to (kept at) 35 degree celcius and forming an adduct with tributyril phosphate, (in kerosene, hexane or dodecene) plus nitric acid. When you apply this supercritical fluid complex to (thermally) pulverized spent fuel, the lantanides (sp?) are dissolved in the fluid and when you remove the pressure from the reaction vessel, CO2 evaporates and you simply have a solution containing U and Pu. Very neat and elegant and most importantly not bulky :). But I must confess that I could not understand how mixture of U and Pu is separated by using redox :eek: .

Anyway here are some links, read yourself :
http://www.cea.fr/gb/publications/Clefs46/pagesg/clefs46_10.html
http://www.ieer.org/sdafiles/vol_5/5-1/purexch.html
http://www.euronuclear.org/info/encyclopedia/p/purex-process.htm
http://www.hindu.com/thehindu/seta/2003/08/21/stories/2003082100060200.htm (Supercritical fluid (i.e. CO2))
http://www.ricin.com/nuke/bg/lahague.html
http://216.239.59.104/search?q=cache:SpuWouhIUkIJ:www.francenuc.org/en_chn/irr_fuel1_e.htm+PUREX+%2BUranium&hl=tr
http://home.austarnet.com.au/davekimble/peakuranium.htm
http://tauon.nuc.berkeley.edu/asia/1999/TPE99Enokida.pdf (Supercritical fluid (i.e. CO2) detailed process)

But the major disappointment I had is Heavy Water processes. The one which looks most promising (i.e. Girdler Sulfide process) (with respect to energy consumption) requires very high colums (more than 90 m high) with several sieves which are hard to hide. Now I am looking for a simple process to have (say a few liters of) heavy water. Anybody know such a process? Maybe process is over there but I somehow missed it.

The processes I found are as follows :

http://www.fas.org/nuke/intro/nuke/heavy.htm (Heavy Water)
http://www.fas.org/irp/threat/mctl98-2/p2sec05.pdf (Heavy Water)
http://www.iraqwatch.org/government/US/DOE/DOE-CHAPTER5.PDF (Heavy Water, some data about the sizes of Heavy Water production (enrichment) facilities)

An interesting neutron generator link :

http://www.lbl.gov/Science-Articles/Archive/neutronGenerator.html

In addition there is an article which I cannot reach. Anybody with a university subscription may have it easily and free of charge. This article is the very article where SCF (supercritical fluid) process is described. So college students (I know there are many amongst us, and majority of them are technical university students I believe) may get this article for the benefit of the forum.

Anyway here it is :
Reference article: O. Tomioka, Y. Enokida, I. Yamamoto, ÒSolvent Extraction of Lanthanides from Their Oxides
with TBP in Supercritical CO2,Ó Journal of Nuclear Science and Technology, 35, 515 (1998).

I have found a relatively promising process for U enrichment. The process is called Aerodynamic enrichment. But I must state that some researchers / authors claim that its capability is exaggerated. This process has been used by South African government to enrich natural Uranium for their breeder reactors.

The process uses either vortex formation in a tapering tube (which actually represents another form of centrifuging (sp?)) or jet nozzles. In the vortex tube setup, vortex is created by injecting UF6 gas diluted with H2 very much at (I believe) an tangential angle at supersonic speeds. (AFAI understand) while heavier isotopes goes down the tube during spinning lighter isotopes leaves the tapering tube's upper (and smaller) hole. This is the setup which South Africans used. Various versions of this setup is used by some developing countries (such as Brazil).

Anyway here are some patent numbers for the process :
3708964, 3989483, 4342727, 3362131, 2951554 (beware! The patents do not contain vortex tube design but expanding jet principle.)

Regarding the Heavy Water processes, I found catalytic processes might be useful for small scale production (enrichment). Here are some patents regarding catalytic deuterium separation. Catalytic process utilizes certain Group VIII elements facilitate transfer of D in hydrogen gas to H2O in liquid (or vapor) phase. By using this method one may obtain small amounts of Heavy Water in a cost efficient manner I believe.

Here are some patents describing various variants of the process :
6858190, 2690379, 4025560, 3681021. (However I cannot find any info on the latest breakthrough called "wetproofed" catalyst, which is important since activity of the catalyst is based on its substrate's hydrophobic character.)

From now on my post is based on my hypotetical discourse. (So sorry if I utter some kewlish / foolish / idiotic / suicidal ideas. This is only food for thought.)

Anyway what I deduced from the latest part of this thread regarding Water Boiler Reactors (hereinafter referred to as WBR(s)) is the difficulties of obtaining LEU (for light water version) or Heavy water (for Natural U) as well as corrosion / pecipitation problems.

Here are some of my ideas regarding to solution of these problems:
Maybe one may use aerodynamic process to obtain LEU for WBRs. As you know LEU is any enriched U whose fissile U content is above natural abundance. So even if improvised setup may attain very low enrichment, one may finally manage to obtain LEU (but I am manifestly omitting here the toxic nature of UF6, explosive properties of H2 used for dilution in the process and asuming that these are overcome/solved).

One of my ideas for solving corrosion problems in WBRs is to plate the inner surfaces of the core (and any other parts thereof necessitating corrosion protection) with lead / teflon / gold / silver or some other substance which is resistant to both chemical corrosion and radiation damage. Lead shall be my personal choice since it's relatively cheaper and easy to apply. An idea for solving precipitation problem is to use cylindrical setup with cooling heat exchanger (aka coils) is placed around the core, instead of which (i.e. inside the core) a special impeller installed at the center, vanes of such impeller are in shape of mirrored Ls. Lower (and horizontal) part is attached to the impeller shaft (at the bottom) and upper (and vertical) part is in contact with the side walls of the cylinder. Lower parts are in contact with the bottom of the cylindirical container (core).

The function of such impeller shall be both to agitate the solution and to (lightly) scrape walls and bottom of the cylindrical core, thereby eliminating problem of
precipitation to a certain extent.

In addition What I believe the precipitation problem arise from is the radioactive decomposition of the sulfate ions, and thereby inducing precipitation of U oxides in the core. So if we plate walls of the core with lead (which I believe resistant to both radiation and SA) and add some SA from time to time, we may compansate the decomposed and consequently missing sulfate ions and thereby prevent formation / precipitation of U oxides.

Regarding the moderator / fuel pair, if we avoid enriching and go through the Natural U course, then some ideas struck in my mind while I was thinking.

First idea was (I believe) entirely kewlish (as you put it). I thought what if we add graphite powder to the light water in the core (for natural U setup) to increase light water's moderating capabilities and circulate and /or agitate it as specified above, in order to prevent settlement. I believe nobody tried this type of makeshift moderator. And most probably it shall not work.

The second idea came to my mind when I was reading an article related to (possible) critically incidents in preparation of MOX fuels.

Here is the article : http://typhoon.tokai.jaeri.go.jp/activity/Criticality%20Safety%20Evaluation%20in%20MOX%20Fue l%20Fabrication%20Process.pdf

According to the article, Zinc Stearate is used as a binder while preparing Mox fuel pellets. And if amount of this binder is too much in the MOX fuel blender, it might act as a moderator and give rise to a criticaly incident. Some figures are given in the article.

In addition, while I was reading about German efforts during WWII for a nuclear device, they tried to use Paraffin wax as moderator for a breeder reactor but then they shifted to heavy water coming from a Norway plant.

So I thought if Zinc stearate may act as a moderator, what if we add some sort of soluble hyrocarbon to the ordinary water and use this mixture as a moderator thereby eliminating need for heavy water. Consequently (please don't laugh at me) I thought adding soap (sodium or potassium soap) to the light water, thereby increasing its moderating capabilities and eliminating need for heavy water for WBRs.

A secondary thought is one may produce low enriched heavy water (with catalytic process) not bothering for pure heavy water and add this (or another more suitable) organic substance to increase its moderating capabilities and placing large (boron free) slabs of graphite around the reactor. Graphite is not only a good moderator but also a good neutron reflector.

But problem with this idea is MOX fuel contains a high percentage of fissile material, but natural U does not. Consequently Zinc Stearate which may act as a moderator for MOX fuel may not do so well for Natural U. Anyway this is only food for thought.

After operating the WBR for three months continuously, you may shut down it with by means of a boron rod and e*tract Pu from the fuel soup. I suggest operating for three months since I once read somewhere Israelis irradiate natural U blankets for three months in order to have optimum Pu with minimum even numbered isotopes for their nuk*es.

What about these ideas? I hope they do not entirely suck :). Regards.

I have found a relatively promising process for U enrichment. The process is called Aerodynamic enrichment. But I must state that some researchers / authors claim that its capability is exaggerated. This process has been used by South African government to enrich natural Uranium for their breeder reactors.

The process uses either vortex formation in a tapering tube (which actually represents another form of centrifuging (sp?)) or jet nozzles. In the vortex tube setup, vortex is created by injecting UF6 gas diluted with H2 very much at (I believe) an tangential angle at supersonic speeds. (AFAI understand) while heavier isotopes goes down the tube during spinning lighter isotopes leaves the tapering tube's upper (and smaller) hole. This is the setup which South Africans used. Various versions of this setup is used by some developing countries (such as Brazil).

Anyway here are some patent numbers for the process :
3708964, 3989483, 4342727, 3362131, 2951554 (beware! The patents do not contain vortex tube design but expanding jet principle.)

Regarding the Heavy Water processes, I found catalytic processes might be useful for small scale production (enrichment). Here are some patents regarding catalytic deuterium separation. Catalytic process utilizes certain Group VIII elements facilitate transfer of D in hydrogen gas to H2O in liquid (or vapor) phase. By using this method one may obtain small amounts of Heavy Water in a cost efficient manner I believe.

Here are some patents describing various variants of the process :
6858190, 2690379, 4025560, 3681021. (However I cannot find any info on the latest breakthrough called "wetproofed" catalyst, which is important since activity of the catalyst is based on its substrate's hydrophobic character.)

From now on my post is based on my hypotetical discourse. (So sorry if I utter some kewlish / foolish / idiotic / suicidal ideas. This is only food for thought.)

Anyway what I deduced from the latest part of this thread regarding Water Boiler Reactors (hereinafter referred to as WBR(s)) is the difficulties of obtaining LEU (for light water version) or Heavy water (for Natural U) as well as corrosion / pecipitation problems.

Here are some of my ideas regarding to solution of these problems:
Maybe one may use aerodynamic process to obtain LEU for WBRs. As you know LEU is any enriched U whose fissile U content is above natural abundance. So even if improvised setup may attain very low enrichment, one may finally manage to obtain LEU (but I am manifestly omitting here the toxic nature of UF6, explosive properties of H2 used for dilution in the process and asuming that these are overcome/solved).

One of my ideas for solving corrosion problems in WBRs is to plate the inner surfaces of the core (and any other parts thereof necessitating corrosion protection) with lead / teflon / gold / silver or some other substance which is resistant to both chemical corrosion and radiation damage. Lead shall be my personal choice since it's relatively cheaper and easy to apply. An idea for solving precipitation problem is to use cylindrical setup with cooling heat exchanger (aka coils) is placed around the core, instead of which (i.e. inside the core) a special impeller installed at the center, vanes of such impeller are in shape of mirrored Ls. Lower (and horizontal) part is attached to the impeller shaft (at the bottom) and upper (and vertical) part is in contact with the side walls of the cylinder. Lower parts are in contact with the bottom of the cylindirical container (core).

The function of such impeller shall be both to agitate the solution and to (lightly) scrape walls and bottom of the cylindrical core, thereby eliminating problem of
precipitation to a certain extent.

In addition What I believe the precipitation problem arise from is the radioactive decomposition of the sulfate ions, and thereby inducing precipitation of U oxides in the core. So if we plate walls of the core with lead (which I believe resistant to both radiation and SA) and add some SA from time to time, we may compansate the decomposed and consequently missing sulfate ions and thereby prevent formation / precipitation of U oxides.

Regarding the moderator / fuel pair, if we avoid enriching and go through the Natural U course, then some ideas struck in my mind while I was thinking.

First idea was (I believe) entirely kewlish (as you put it). I thought what if we add graphite powder to the light water in the core (for natural U setup) to increase light water's moderating capabilities and circulate and /or agitate it as specified above, in order to prevent settlement. I believe nobody tried this type of makeshift moderator. And most probably it shall not work.

The second idea came to my mind when I was reading an article related to (possible) critically incidents in preparation of MOX fuels.

Here is the article : http://typhoon.tokai.jaeri.go.jp/activity/Criticality%20Safety%20Evaluation%20in%20MOX%20Fue l%20Fabrication%20Process.pdf

According to the article, Zinc Stearate is used as a binder while preparing Mox fuel pellets. And if amount of this binder is too much in the MOX fuel blender, it might act as a moderator and give rise to a criticaly incident. Some figures are given in the article.

In addition, while I was reading about German efforts during WWII for a nuclear device, they tried to use Paraffin wax as moderator for a breeder reactor but then they shifted to heavy water coming from a Norway plant.

So I thought if Zinc stearate may act as a moderator, what if we add some sort of soluble hyrocarbon to the ordinary water and use this mixture as a moderator thereby eliminating need for heavy water. Consequently (please don't laugh at me) I thought adding soap (sodium or potassium soap) to the light water, thereby increasing its moderating capabilities and eliminating need for heavy water for WBRs.

A secondary thought is one may produce low enriched heavy water (with catalytic process) not bothering for pure heavy water and add this (or another more suitable) organic substance to increase its moderating capabilities and placing large (boron free) slabs of graphite around the reactor. Graphite is not only a good moderator but also a good neutron reflector.

But problem with this idea is MOX fuel contains a high percentage of fissile material, but natural U does not. Consequently Zinc Stearate which may act as a moderator for MOX fuel may not do so well for Natural U. Anyway this is only food for thought.

After operating the WBR for three months continuously, you may shut down it with by means of a boron rod and e*tract Pu from the fuel soup. I suggest operating for three months since I once read somewhere Israelis irradiate natural U blankets for three months in order to have optimum Pu with minimum even numbered isotopes for their nuk*es.

What about these ideas? I hope they do not entirely suck :). Regards.

http://www.worldnewsstand.net/4fun/bigbang.htm

a comical site on the same topic...

http://www.worldnewsstand.net/4fun/bigbang.htm

a comical site on the same topic...

Dear Friends,

During the last few days, I made some more research into the subject matter hereof, and developed some (I hope not kewlish) ideas regarding this.

First of all, I would like to address the LEU problem. In addition to Aerodynamic enrichment processes, there is another process called chemical exchange and ion exchange enrichment. These processes are based on the phenomenon that lighter isotopes have a tendency to be present in higher oxidation states (higher valance values).

Another most important aspect of these processes is that they do not use toxic and corrosive gases (called HEX), and complicated mechanic systems (like compressors, piping, fittings, centrifuges, etc.) The (both) processes are very similar to P*UR*EX process, utilizing TBP and kerosene (hereinafter referred to extraction solvent - ES) and chloride salts of U. While ES contains higher valance U chloride salts, the aqueous phase contains lower valance U chloride salts. Both phases are placed in a pulse column and pulsed for ensuring intimate mixing. There occurs an isotope exchange between two phases : while ligher isotopes (in aqueous phase) migrate to ES phase, the heavier isotopes in ES phase migrate to aqueous phase. During this operation certain catalysts increase exchange rate in the order of 3000.

After this stage two different approaches are used for extracting the both fractions (one enriched fraction and one depleted fraction). Either they are separated in Pu*R*EX process or they are forced through a (proprietary) ion exchange resin and separated efficiently.

Since the ion exchange resin is proprietary (i.e. ambigious), I would personally chose the first approach. Since these processes (except for ion exchange resin) are very similar to dairy churning process, I call them churning process. If one can use the first process with the aid of catalysts, one may obtain LEU for WBRs referred to further above.

Both processes are described quite clearly in the link below :

http://www.fas.org/nuke/intro/nuke/uranium.htm

The most advantageous aspect of these processes is (IMHO) they are not energy extensive. They are performed at relatively mild temperatures and pressures and do not need those complex centrifuges, pipings, fittings and most importantly highly corrosive and toxic fluorides, etc. However, they have to be performed several thousand times to obtain a good enrichment (a setup which applies not only to this process but to almost any any enrichment processes in form of cascades).

If the chemical enrichment process is used in combination with the vague catalysts referred to in Patent No 4049769 then it might be possible to enrich U at least up to LEU level.

Here are patents for the above mentioned processes :
4049769 (this patent is related to Ion Exchange process whose exchange rate is increased by a factor of 3000 by means of various (and vague) catalyst(s).)
4092398 (Isotope (ion) exchange process using a proprietary ion exchange resin)
4112045
4129481

BTW, I think our concerns over the Th cycle is a little bit unnecessary. The harsh gamma emmiter contaminants of irradiated th (i.e. Bismuth 212 and Thalium 208) are very short lifed (in the order of minutes). Sources :
http://www.angelfire.com/yt/radiation/radon.html
http://wildlife1.usask.ca/ccwhc2003/short_course2000/tox-3.htm

The ancestor of above mentioned harsh gamma emitter contaminants, i.e. U-232 is an alpha emitter and (I believe) it can be totally eliminated by using chemical and ion exchange processes. Of course such isotopic elimination processes must be performed after the spent fuel is left to cool down (in order to allow for the gamma emitters to decompose /decay).

The most advantageous aspects of U-233 is its small critical mass which makes it ideal for artillery shells. While there are artillery shells utilizing Pu, it's not a suitable thing since it's wasteful of the Pu used (with respect to amount of Pu used and the very low yield obtained).

In addition, my ideas regarding use of organic materials for moderating reactors are not totally baseless. During the searches over the net, I came across a new (but actually quite old) concept called organically moderated reactors, which use certain polyphenols as moderator. However, since they are totally experimental I cannot find any references regarding its fuel composition except for it's slightly enriched.

In addition, there is an article regarding OMRs (organically moderated reactors) which states the TBP-kerosen solvent pair as moderator. However the fuel composition (I believe) is HEU.
Anyway here is the link :
http://www.csirc.net/docs/technical/12808/ref_077.pdf

The catalytic heavy water enrichment processes are quite promising. Here is a link describing a catalytic enrichment process quite clearly. There is a better wet-proofed catalyst in the patents than those described in this paper.

Anyway here is the paper
http://nrd.pnpi.spb.ru/lriv/Marseille173.PDF.

Dear Friends,

During the last few days, I made some more research into the subject matter hereof, and developed some (I hope not kewlish) ideas regarding this.

First of all, I would like to address the LEU problem. In addition to Aerodynamic enrichment processes, there is another process called chemical exchange and ion exchange enrichment. These processes are based on the phenomenon that lighter isotopes have a tendency to be present in higher oxidation states (higher valance values).

Another most important aspect of these processes is that they do not use toxic and corrosive gases (called HEX), and complicated mechanic systems (like compressors, piping, fittings, centrifuges, etc.) The (both) processes are very similar to P*UR*EX process, utilizing TBP and kerosene (hereinafter referred to extraction solvent - ES) and chloride salts of U. While ES contains higher valance U chloride salts, the aqueous phase contains lower valance U chloride salts. Both phases are placed in a pulse column and pulsed for ensuring intimate mixing. There occurs an isotope exchange between two phases : while ligher isotopes (in aqueous phase) migrate to ES phase, the heavier isotopes in ES phase migrate to aqueous phase. During this operation certain catalysts increase exchange rate in the order of 3000.

After this stage two different approaches are used for extracting the both fractions (one enriched fraction and one depleted fraction). Either they are separated in Pu*R*EX process or they are forced through a (proprietary) ion exchange resin and separated efficiently.

Since the ion exchange resin is proprietary (i.e. ambigious), I would personally chose the first approach. Since these processes (except for ion exchange resin) are very similar to dairy churning process, I call them churning process. If one can use the first process with the aid of catalysts, one may obtain LEU for WBRs referred to further above.

Both processes are described quite clearly in the link below :

http://www.fas.org/nuke/intro/nuke/uranium.htm

The most advantageous aspect of these processes is (IMHO) they are not energy extensive. They are performed at relatively mild temperatures and pressures and do not need those complex centrifuges, pipings, fittings and most importantly highly corrosive and toxic fluorides, etc. However, they have to be performed several thousand times to obtain a good enrichment (a setup which applies not only to this process but to almost any any enrichment processes in form of cascades).

If the chemical enrichment process is used in combination with the vague catalysts referred to in Patent No 4049769 then it might be possible to enrich U at least up to LEU level.

Here are patents for the above mentioned processes :
4049769 (this patent is related to Ion Exchange process whose exchange rate is increased by a factor of 3000 by means of various (and vague) catalyst(s).)
4092398 (Isotope (ion) exchange process using a proprietary ion exchange resin)
4112045
4129481

BTW, I think our concerns over the Th cycle is a little bit unnecessary. The harsh gamma emmiter contaminants of irradiated th (i.e. Bismuth 212 and Thalium 208) are very short lifed (in the order of minutes). Sources :
http://www.angelfire.com/yt/radiation/radon.html
http://wildlife1.usask.ca/ccwhc2003/short_course2000/tox-3.htm

The ancestor of above mentioned harsh gamma emitter contaminants, i.e. U-232 is an alpha emitter and (I believe) it can be totally eliminated by using chemical and ion exchange processes. Of course such isotopic elimination processes must be performed after the spent fuel is left to cool down (in order to allow for the gamma emitters to decompose /decay).

The most advantageous aspects of U-233 is its small critical mass which makes it ideal for artillery shells. While there are artillery shells utilizing Pu, it's not a suitable thing since it's wasteful of the Pu used (with respect to amount of Pu used and the very low yield obtained).

In addition, my ideas regarding use of organic materials for moderating reactors are not totally baseless. During the searches over the net, I came across a new (but actually quite old) concept called organically moderated reactors, which use certain polyphenols as moderator. However, since they are totally experimental I cannot find any references regarding its fuel composition except for it's slightly enriched.

In addition, there is an article regarding OMRs (organically moderated reactors) which states the TBP-kerosen solvent pair as moderator. However the fuel composition (I believe) is HEU.
Anyway here is the link :
http://www.csirc.net/docs/technical/12808/ref_077.pdf

The catalytic heavy water enrichment processes are quite promising. Here is a link describing a catalytic enrichment process quite clearly. There is a better wet-proofed catalyst in the patents than those described in this paper.

Anyway here is the paper
http://nrd.pnpi.spb.ru/lriv/Marseille173.PDF.

Regarding the NRDC and their one kilogram - one kiloton prediction... it seems to me that it is fully possible to release the energy equivalent of one kiloton from one kilogram of U-233 or Plutonium. Carry Sublette states this in his nuclear FAQ. However, he also states that this yield could only be achieved through the use of advanced flying plate-levitated core nuclear weapon designs. Sublette, in his nuclear FAQ, also makes mention of the use of D-T boosting in such low fissile material - low yield devices. An efficient reflector material, such as Beryllium, is also a requirement... This, however, does not make my original statment of 16Kg incorrect for U-233's bare sphere critical mass. Carry Sublette derived this figure on the basis of one group calculations, which seem to be accurate given the fact that the calculations agree with Los-Alamos' published data. (Which is, unfortunanly, removed from the public domain. Most of what is left is available on www.fas.org... Ill see if I can find the link)

Regarding the NRDC and their one kilogram - one kiloton prediction... it seems to me that it is fully possible to release the energy equivalent of one kiloton from one kilogram of U-233 or Plutonium. Carry Sublette states this in his nuclear FAQ. However, he also states that this yield could only be achieved through the use of advanced flying plate-levitated core nuclear weapon designs. Sublette, in his nuclear FAQ, also makes mention of the use of D-T boosting in such low fissile material - low yield devices. An efficient reflector material, such as Beryllium, is also a requirement... This, however, does not make my original statment of 16Kg incorrect for U-233's bare sphere critical mass. Carry Sublette derived this figure on the basis of one group calculations, which seem to be accurate given the fact that the calculations agree with Los-Alamos' published data. (Which is, unfortunanly, removed from the public domain. Most of what is left is available on www.fas.org... Ill see if I can find the link)

While surfing I came across these two goodies about WBRs.
:D
Here are the links :
http://www.lib.ncsu.edu/archives/etext/engineering/reactor/NEprop033050.html
http://www.lib.ncsu.edu/archives/etext/engineering/reactor/NEfurther010052.html

While surfing I came across these two goodies about WBRs.
:D
Here are the links :
http://www.lib.ncsu.edu/archives/etext/engineering/reactor/NEprop033050.html
http://www.lib.ncsu.edu/archives/etext/engineering/reactor/NEfurther010052.html

The collection of uranium from seawater has been developed by JAEA. A pilot scale experiment in the sea revealed that a braided adsorbent was effective to achieve a reasonable cost for the uranium collection from seawater.

Aquaculture of Uranium in Seawater by a Fabric-Adsorbent Submerged System
Nuclear Technology, Volume 144, Number 2, November 2003, Pages 274-278
http://www.ans.org/pubs/journals/nt/va-144-2-274-278

Assessing High Function Metal Collectors for Seawater Uranium
http://jolisfukyu.tokai-sc.jaea.go.jp/fukyu/mirai-en/4_5.html
(attached)

I read about that uranium collection scheme years ago in Popular Science. There is enough uranium in seawater to supply all of the worlds electrical power needs for generations, but we would have to process a daily volume of water equal to the volume of water the worlds rivers dump into the oceans. This is no easy, or cheap, feat.

Gold, silver, platinum, and other precious metals can also be extracted from seawater increasing the commercial value of such an endeavor.

This material extracts the uranium from ocean water at a cost that is almost equal to commercially mined uranium from the ground, when the filters lifespan is factored in.

Even at 10x the cost, it'd be worth it to a country with no natural uranium deposits, because they wouldn't have to risk importing any, thus exposing their interest in such.

The neat thing about this is that uranium is universally present in seawater, regardless of geography, making impossible any attempt at preventing access to fissionable materials to countries that have access to the sea. :p

I may get banned for this but I believe even the most morose of people with a chem clue would find it hilarious. I found it on a google search for improvised atomic weapons.

It says you can use a bicycle pump for pressure needed to enrich the U.

http://www.totse.com/en/bad_ideas/ka_fucking_boom/hbomb.html

(NBK, it has NO paragraph breaks so you might pull your hair out reading it)

[I have come to note that] posting issues explored in "totse" are greeted with the same disdain by the proprietor as referring to Martin Luther King as a "Alabama Silverback" in an NAACP collective. {au lait faux paux?}

It's always fun to see what's happening on the other side of the tracks...deep in the inbred woods. ;)

Hey, that hurts.

Don't lump the forums in with the textfiles.

TOTSE has some very good information, they have all the explosives stuff they ripped from my website :) Beyond that... inbred does not even begin to describe it. They make the Africans who rape toddlers as a cure for AIDS sound enlightened.

You really need to bring back the Watercooler... I could see this thread go on a tangent for weeks.

You don"t need 100% pure u-235 but just enough to sustain a reaction.
A gun-type could be more of a challenge because you need to work out how much high explosives you need to force the projectil hard and fast enough to 'weld' the two together. How ever the implosion method just requieres exact timeing of all of the explosives and all of the explosives must be the exact same. Also the implosion method requires two more radioactive materials (for national security they will not be named).

It is possable for terrorists to get such materials at places like Chernobyl.
How ever there could be a easier way to make such a weapon ( if anyone is interested to find out reaspond to this message).

In gerneral it is hard to make a homemade nuke let alone get it to work properly.

How ever the implosion method just requieres exact timeing of all of the explosives and all of the explosives must be the exact same.


Not that simple, implosion method also requires precision shaping of the shockwave fronts so each shockwave from each explosive lenses converge in the center of the sphere, which makes it a pain in the heinie to design explosive lenses.

In addition, explosive lenses require precision manufacturing techniques which precludes presence of any bubbles, flaws or failures in the texture of the explosive mass(es) used in the lens.


Also the implosion method requires two more radioactive materials (for national security they will not be named).

I doubt it. Maybe you are referring to neutron sources (i.e. polonium and berrylium) used in the beginning of the technology.

However nowadays, electronic neutron sources are used. Regards.

There is a web site that you can download nuclear bomb plans: www.linkbase.org.

A nuclear bomb does not require tons of nuclear material. A nuclear bomb requires a very small amount of nuclear material compared to the amount of High Explosives it requires. It takes vast amount of energy to convert elements from one to another(unless you're a plant) so the idea of a 15 year old kid doing so is, in my mind, infeasible. A nuclear bomb to my knowledge however limited it may be, consists of a core of nuclear material, surrounded by thousands of pounds of high explosives. The outer layer detonates, compressing the nuclear material to critical mass. Sort of like the death of a star. An implosion, THEN the explosion. The forces exerted must be I-fucking-dentical, for the fission to take place, so all the high explosives must detonate precisely the same instant. Which is where the hard part comes in. But dont quote me on it.

If one had the Plutonium or Uranium how hard would it be to construst a nuclear device? From what I have read it really doesn't sound that difficult, especially a gun type. I think the implosion type device would be more of a challenge.
I have no interest in building such a thing but I was thinking if a terrorist group was to obtain the fissionable material it might not be too difficult for them to do it.
What do you guys think?
1. Anyone with a fair amount of resources, access to the internet, and masters or possibly even a bachelors degree in physics could make the crude gun barrel type nuke if they had the money (it would still cost thousands) and the uranium
2. The above point is almost completely moot as obtaining weapons grade (95% pure) U-235 (the material used in said simple nuke) is one of the most difficult tasks in the world, as it is one of the most sought after and dangerous substances in the world. Refining non-weapons grade U-238 such as is contained in power plants (roughly 2-3% U-235) requires an extrordinarily tedious and monumentously expensive (in the order of hundreds of millions of dollars) to make, so any ideas of simply getting nuclear material from chernobyl are at best the realm of a bad techno-thriller novel. The only other way to obtain weapons grade U-235 is by attempting to steal it from a nuclear nation, an idea so ludicrous, it can reasonably be classified as a suicide attempt.

3. While it is possible to use much easier to get plutonium to make a nuclear bomb, the bomb making is much more difficult, requires lots of precision engineering, millions of dollars, and a large industrial complex as the specifications for the device (an "implosion" type) have to have ludicrously high tolerances, completely unachievable by any one person or even a small group.

4. So inconclusion, the only type that is easy to make requires a fair bit of weapons grade U-235, which is nearly impossible to obtain, if by some miracle you managed to get enough for a bomb, then yes, in theory, you could make a crude nuclear device.

I'm not 100%, but I'm fairly certain that you could make a gun type nuclear bomb out of Plutonium, it doesn't have to be Uranium.

You are correct, Necrophagist. Plutonium can be used in a gun type device.

I'm fairly certain that you could make a gun type nuclear bomb out of Plutonium

You are correct, Necrophagist. Plutonium can be used in a gun type device.

I was under the impression that Plutonium had to high a fissile rate to used in a gun-type bomb?

A gun type bomb must be made from uranium-235. Plutonium cannot work at the usual velocities due to Plutonium-240 spontaneous fission. Now, theoretically a gun type device using plutonium is possible, but the velocities necessary are ludicrous (being perhaps on the order of 2km/s or so). In such cases, I feel a true linear implosion would constitute the simplest Plutonium system since it can achieve the necessary velocities for insertion without the prohibitively large/heavy gun barrel. Such a system would be similar, in some respects, to the Explosively formed projectors currently in use ... except they would have to make use of a relatively accurate planar explosive lens in order to accelerate the (I imagine disk-like) plutonium projectile into the Pu-239 "target".

Please follow this attachment word for word.:D:rolleyes::cool: Also youll need some sunblock for these ones:D