India's Second Indigenous 700 MW Nuclear Reactor Moves Closer to Commercial Operation After Achieving First Criticality

India's second domestically constructed 700 MW nuclear power reactor in Kakrapar, Gujarat, hit first criticality, or commencement of the controlled, self-sustaining nuclear fission chain reaction, early on Sunday (17 December).

This milestone paves the way for its gradual progression towards generating electricity for commercial use.

The first criticality was obtained at 1.17 am under the supervision of B C Pathak, the Chairman and Managing Director of the Nuclear Power Corporation of India Limited (NPCIL).

The Kakrapar Atomic Power Project's Unit-4 is the second of 16 domestically produced Pressurised Heavy Water Reactors, each with a capacity of 700 MW, that are being established in the country.

"Achievement of the criticality of KAPP-4 within six months of commercial operation of Unit-3 was significant," Pathak said, addressing officials at the site.

An NPCIL statement confirmed that criticality was achieved after all conditions set by the Atomic Energy Regulatory Board (AERB) were met. The AERB had granted clearance following a stringent safety review of the plant systems.

Following first criticality, a series of tests and experiments will be carried out in KAPP-4. The power level will be gradually increased per AERB clearances, with the final goal being the full-power operation of the unit.

"KAPP-4 steps closer to generating #CleanEnergy - the achievement aligns with India's pledge for netzero emissions, as highlighted by Hon’ble Prime Minister Shri Narendra Modi ji, reinforcing the crucial role of #NuclearPower in combating climate change," the Department of Atomic Energy said in an X post.

The KAPP-3 and -4 reactors, each with a capacity of 700 MW, are situated in Kakrapar within the Surat district of Gujarat. They are positioned next to the pre-existing KAPS-1 and -2 reactors, each with a capacity of 220 MW.

The NPCIL asserts that these native PHWRs, equipped with superior safety features, rank among the world's safest reactors.

The NPCIL has been responsible for the design, construction, commissioning, and operation of these reactors, according to the corporation. However, the provision of equipment and implementation of contracts have been undertaken by the Indian industry.

Currently, the NPCIL manages 23 reactors that have a combined capacity of 7,480 MW. Additionally, there are nine units, KAPP-4 included, under construction that will provide a capacity of 7,500 MW.

Furthermore, pre-project activities are underway for an additional 10 reactors that have a combined capacity of 7,000 MW. The completion of these projects is anticipated by the years 2031-32.