IPHWR-700

The IPHWR-700 (Indian Pressurized Heavy Water Reactor-700) is an Indian pressurized heavy-water reactor designed by Bhabha Atomic Research Centre[1]. It is a Generation III+ reactor developed from earlier 220 MW and 540 MW designs and can generate 700 MW of electricity. Currently there are 6 units under construction and 10 more units planned at a cost of INR 1.05 trillion (US$ 14 billion)

IPHWR-700 Reactor Class
Kakrapar Atomic Power Station reactor units 3 and 4, under construction in the Indian state of Gujarat
Generation	Generation III reactor
Reactor concept	pressurized heavy-water reactor
Reactor line	IPHWR
Status	6 under construction 10 planned
Main parameters of the reactor core
Fuel (fissile material)	^235U (NU/SEU/LEU)
Fuel state	Solid
Neutron energy spectrum	Thermal
Primary control method	control rods
Primary moderator	Heavy water
Primary coolant	Heavy water
Reactor usage
Primary use	Generation of electricity
Power (thermal)	2166 MWth
Power (electric)	700 MWe

Development

The PHWR technology was introduced in India in the late 1960s with the construction of RAPS-1 CANDU reactor in Rajasthan. All the main components for first unit were supplied by Canada while India did the construction, installation and commissioning job. In 1974 after India conducted Smiling Buddha, its first nuclear weapons test Canada stopped their support of the project, delaying the commissioning of RAPS-2 until 1981.[2]

After Canadian withdrawal from project, research, design and development work in Bhabha Atomic Research Centre and Nuclear Power Corporation of India (NPCIL) along with some industry partners who did the manufacturing and construction work enabled India in establishing this technology in totality. Over four decades, 15 220 MW reactors of indigenous design were built. Improvements were made in the original CANDU design to reduce construction time and cost, new safety systems were incorporated and thus reliability was enhanced leading to better capacity factors. Realising the economics of scale, a 540 MW design was developed by NPCIL. 2 units of this design were constructed at the Tarapur Atomic Power Station. Further optimisations were carried out to utilise the excess thermal margins and the 540 MW PHWR design was modified to that of 700 MW capacity without much design changes. Almost 100% of the components of these indigenously designed reactors are manufactured by the Indian industry.[3]

Design

Like other pressurized heavy-water reactors, IPHWR-700 uses heavy water (deuterium oxide D₂O) as its coolant and neutron moderator. The design retains the features of standardized Indian PHWR units, which include:[4]

I-PHWR700 Model installed in GCNEP Office, Haryana

• Two diverse and fast acting shutdown systems
• Double containment of reactor building
• Water filled calandria vault
• Integral calandria - end shield assembly
• Zr-2.5% Nb pressure tubes separated from respective calandria tubes
• Calandria tube filled with carbon dioxide (which is recirculated) to monitor pressure tube leak

It also includes some new features as well. These include:

• Partial boiling at the coolant channel outlet
• Interleaving of primary heat transport system feeders
• Passive decay heat removal system
• Regional over power protection
• Containment spray system
• Mobile fuel transfer machine
• Steel lined containment wall

The reactor has very less excess reactivity because of which it does not need neutron poison inside the fuel or moderator. These provisions are made in design to handle the case of a loss of coolant accident which caused Fukushima Daiichi nuclear disaster.[5]

Operation

The reactor uses 0.7% enriched uranium with Zircaloy-4 cladding as fuel. The core produces 2166 MW of heat which is converted into 700 MW of electricity at an efficiency of 32%. Because of lack of excess reactivity inside the reactor, it needs to be refuelled continuously during operation. The reactor is designed for an estimated life of 60 years.[6]

Reactor fleet

Reactors under construction

Power station	Operator	State	Units	Total capacity	Expected Commercial Operation[7]
Kakrapar Unit 3 and 4	NPCIL	Gujarat	700 x 2	1,400	2020
Rajasthan Unit 7 and 8	NPCIL	Rajasthan	700 x 2	1,400	2022[8]
Gorakhpur Unit 1 and 2	NPCIL	Haryana	700 x 2	1,400	2025[8][9]

Reactors planned[10]

Power station	Operator	State	Units	Total capacity
Mahi Banswara	NPCIL	Rajasthan	700 x 4	2,800
Kaiga	NPCIL	Karnataka	700 x 2	1,400
Chutka	NPCIL	Madhya Pradesh	700 x 2	1,400
Gorakhpur	NPCIL	Haryana	700 x 2	1,400

References

1. "ANU SHAKTI: Atomic Energy In India". BARC.
2. "Rajasthan Atomic Power Station (RAPS)". Nuclear Threat Initiative. 1 September 2003. Retrieved 18 February 2017.
3. "Pressurised Heavy Water Reactor". PIB. Dr. S Banerjee.
4. "Status report 105 - Indian 700 MWe PHWR (IPHWR-700)" (PDF). IAEA.
5. "Advanced Large Water Cooled Reactors" (PDF). IAEA.
6. "Advanced Large Water Cooled Reactors" (PDF). IAEA.
7. "Bright prospects for India's future fleet". Nuclear Engineering International. Retrieved 2020-04-13.
8. "Annual Report 2018-19 DAE" (PDF). Department of Atomic Energy. Retrieved 13 February 2020.
9. "First phase Gorakhpur Haryana Atomic Power Plant expected to be completed in 2025". Business Standard. Retrieved 2 January 2019.
10. "Setting up of Ten Indigenous Nuclear Power Reactors". Press Information Bureau. Retrieved 19 July 2018.