Pahute Mesa

Pahute Mesa or Paiute Mesa is one of four major nuclear test regions within the Nevada National Security Site (NNSS). It occupies 243 square miles (630 km²) in the northwest corner of the NNSS in Nevada. The eastern section is known as Area 19 and the western section as Area 20.[1][2]

This article is about the nuclear test region. For the landform extending further northwest, see Pahute Mesa (landform). For other uses, see Pahute (disambiguation).

Location of Pahute Mesa within the Nevada National Security Site

History

The Partial Test Ban Treaty of 1963 banned atmospheric nuclear testing. This led to a requirement for an underground test area that could accommodate higher yield tests than Yucca Flat.

Pahute Mesa was seen as ideal due to its geology and distance of over 160 kilometers (99 mi) from Las Vegas. Holes can be drilled to a depth of more than 1,370 meters (4,490 ft). This allows tests in the megaton range to be fully contained with minimal ground motion being felt in Las Vegas.

Pahute Mesa was thus incorporated into the boundary of the NNSS in late 1963 under an agreement between the United States Atomic Energy Commission and the U.S. Air Force.[3]

Geology and climate

Aerial view of Pahute Mesa

Pahute Mesa is part of the Tonopah Basin and includes the Silent Canyon caldera complex of the Southwest Nevada volcanic field.

Rugged terrain features and harsh winter conditions make year-round operations difficult.

Nuclear testing

A total of 85 nuclear tests were conducted in Pahute Mesa between 1965 and 1992.[2] Three of them—Boxcar, Benham and Handley—had a yield of over one megaton.[2] Three tests were conducted as part of operation Plowshare and one as part of Vela Uniform.[2]

The Soviet Union flag is raised to the top of the emplacement tower to be flown beside the U.S. flag for the Kearsarge test.

In 1988, as a prelude to the signing of the protocols to the Threshold Test Ban Treaty and the Peaceful Nuclear Explosions Treaty, the United States and the Soviet Union conducted two joint tests employing proposed treaty verification techniques. The first was Kearsarge, conducted in Area 19 of the NNSS, the second Shagan, conducted at the Semipalatinsk Test Site.[2]

Shot Greenwater was planned for 1993 and abandoned in place in Area 19 following 1992's testing moratorium.[4]

Radioactive contamination

The following tests resulted in a release of radioactivity that was detected outside of the NNSS.[2]

Test	Date	Type	Purpose	Location	Atmospheric release of iodine-131
Palanquin	1965-04-14	Crater	Plowshare	Area 20	910 kilocuries (34 PBq)[5]
Cabriolet	1968-01-26	Crater	Plowshare	Area 20	6 kilocuries (0.22 PBq)[5]
Schooner	1968-12-08	Crater	Plowshare	Area 20	15 kilocuries (0.56 PBq)[5]

The Schooner plume spread plutonium and other radionuclides across Area 20 and northward into Nellis Air Force Range.[6] According to measurements taken in 2001, the Schooner crater has the highest annual mean concentration of radioactive tritiated water of any area of the NNSS.[7]

Other uses

Apollo 16 astronauts train in the Lunar rover by driving over a near-lunar landscape at the Schooner crater site in Area 20

The Schooner crater area resembles the lunar landscape. It was used along with other areas of the NNSS to train some of the astronauts of the Apollo program, among them Neil Armstrong, Dick Gordon, Buzz Aldrin, Dave Scott and Rusty Schweickart. In 1970, the Apollo 16 team of John Young and Charlie Duke trained at Schooner in the lunar rover.[8]

Supporting infrastructure

The Pahute Control Point is located in Area 18, south of Pahute Mesa. It was used until 1971 to monitor tests in Pahute Mesa.

The Pahute Mesa Airstrip, also in Area 18, was used to ship supplies and equipment to Pahute Mesa.[1]

References

1. U.S. Department of Energy, National Nuclear Security Administration, Nevada Site Office (July 2011), "chapter 2" (PDF), Draft Site-Wide Environmental Impact Statement NevadaCS1 maint: multiple names: authors list (link)
2. U.S. Department of Energy, Nevada Operations Office (December 2000), United States Nuclear Tests - July 1945 through September 1992 (PDF), archived from the original (PDF) on 2006-10-12
3. Hechanova, A.E.; O’Neill, L.J. (May 1998), Description of the Nevada Test Site and Nellis Air Force Range Complex Activities in Nevada, Las Vegas, NV: Harry Reid Center for Environmental Studies, University of Nevada
4. U.S. Department of Energy, Nevada Operations Office (January 2011). "Icecap" (PDF). Fact Sheets. Archived from the original (PDF) on 2011-09-27.
5. National Cancer Institute. National Institute of Health. Chapter 2. History of the Nevada Test Site and Nuclear Testing Background.
6. Globalsecurity.org. Weapons of Mass Destruction. Library. Nevada Test Site Final Environmental Impact Statement. Figure 4-30: Approximate area of plutonium contamination exceeding 10 pCi/g on the NTS.
7. Bechtel Nevada Corporation (October 2001), Annual Site Environmental Report for Calendar Year 2001
8. U.S. Department of Energy, National Nuclear Security Administration, Nevada Operations Office (June 2004). "Apollo Astronauts Train at the Nevada Test Site" (PDF). Fact Sheets.CS1 maint: multiple names: authors list (link)

 This article incorporates public domain material from websites or documents of the United States Department of Energy.