Contents

IPHWR-700

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 (Indian Pressurized Heavy-water Reactor)
Designed by	NPCIL
Manufactured by	NPCIL
Status	2 operational 4 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

The IPHWR-700 (Indian Pressurized Heavy Water Reactor-700) is an Indian pressurized heavy-water reactor designed by the NPCIL.^[1] It is a Generation III reactor developed from earlier CANDU based 220 MW and 540 MW designs. It can generate 700 MW of electricity. Currently there is two unit operational, 6 units under construction and 8 more units planned, at a cost of ₹1.05 lakh crore (US$13 billion).

Development[edit]

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

After Canada withdrew from the project, research, design and development work in the Bhabha Atomic Research Centre and Nuclear Power Corporation of India (NPCIL) enabled India to proceed without assistance. India took help of Soviet Union whose VVER(Pressurised Water Reactor type) technology was used as a design for indigenization. Some industry partners did manufacturing and construction work. Over four decades, fifteen 220-MW reactors of indigenous design were built. Improvements were made in the original VVER design to reduce construction time and cost. New safety systems were incorporated. Reliability was enhanced, bringing better capacity factors and lower costs.

To get economies of scale, NPCIL developed a 540 MW design. Two of these were constructed at the Tarapur Atomic Power Station.

After a redesign to utilise excess thermal margins, the 540 MW PHWR design achieved a 700 MW capacity without many design changes. Almost 100% of the parts of these indigenously designed reactors are manufactured by Indian industry.^[3]

Design[edit]

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 other standardized Indian PHWR units, which include:^[4]

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

It also has some new features as well, including:

• Partial boiling at the coolant channel outlet
• Interleaving of primary heat transport system feeders
• A system to remove passive decay heat
• Regional protection from over power
• A containment spray system
• A mobile fuel transfer machine
• A steel lined containment wall

The reactor has less excess reactivity. Therefore, it does not need neutron poison inside the fuel or moderator. These designs handle the case of a loss of coolant accident such as occurred in the Fukushima Daiichi nuclear disaster.^[5]

Operation[edit]

The reactor fuel uses natural uranium fuel with Zircaloy-4 cladding. The core produces 2166 MW of heat which is converted into 700 MW of electricity at a thermal efficiency of 32%. Because there is less excess reactivity inside the reactor, it needs to be refuelled continually during operation. The reactor is designed for an estimated life of 40 years.^[6]

Unit 3 of Kakrapar Atomic Power Station was connected to the grid on 10 January 2021.^[7]

Reactor fleet[edit]

Technical specifications[edit]

See also[edit]

• IPHWR, a class of Indian PHWRs.
• IPHWR-220, earlier lower power variant of IPHWR-700
• CANDU, predecessor to Indian PHWR designs
• AHWR-300, thorium fuelled PHWR design for the Indian Three stage nuclear power programme
• India's three-stage nuclear power programme
• Nuclear power in India

References[edit]