On December 17, 2023, a significant achievement unfolded at Unit 4 of India’s Kakrapar Atomic Power Project (KAPP 4–700 MW). The reactor successfully entered the criticality phase, displaying the initiation of a controlled fission chain reaction.
What is Criticality?
In the realm of nuclear reactors, criticality is the state where the fission of nuclear materials occurs, producing neutrons in a quantity that matches or surpasses the containment’s capacity. In routine reactor functioning, the nuclear fuel maintains a continuous fission chain reaction called criticality.
Criticality is attained, and a reactor is deemed critical when each fission event releases a satisfactory number of neutrons to sustain an uninterrupted sequence of reactions.
KAPP-4 Attains Criticality
At 1:17 AM on December 17, the fourth unit of the Kakrapar Atomic Power Project (KAPP-4) in Gujarat achieved a significant milestone by initiating a controlled fission chain reaction, officially reaching the criticality phase.
Located approximately 80 km from Surat, Kakrapar is now home to the giant indigenous nuclear power reactors, boasting a capacity of 700 MWe. This achievement is attributed to the Nuclear Power Corporation of India Limited (NPCIL), a public sector undertaking under the Department of Atomic Energy.
The 700 MWe units mark a noteworthy accomplishment, with unit-3 of KAPP having commenced commercial electricity generation on August 30. Operating as pressurised heavy water reactors (PHWRs), these reactors utilise natural uranium as fuel and heavy water as both coolant and moderator. The successful operation of these reactors underscores India’s progress in nuclear energy. It highlights the strategic contributions of NPCIL in this domain.
This milestone results from a meticulous adherence to safety guidelines established by the Atomic Energy Regulatory Board (AERB), which thoroughly examined the plant systems’ safety measures. KAPP-4 is the second unit in a series of sixteen indigenous pressurised heavy Water Reactors (PHWR), each boasting a 700 MW capacity currently under construction in the country.
With the achievement of criticality, KAPP-4 is now poised for a series of experiments and tests. The power level will gradually increase, subject to approvals and clearances from the Atomic Energy Regulatory Board (AERB). This step-by-step process is designed to culminate in the unit’s operation at its maximum power capacity, demonstrating a systematic and controlled approach to nuclear reactor development.
BC Pathak, CMD of NPCIL, had a front-row seat to witness the momentous event in the control room of the Kakrapar Atomic Power Project. Alongside the site team, he observed the criticality achievement unfold. Meanwhile, officials at NPCIL Headquarters in Mumbai witnessed the event through a video link.
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In the aftermath of this significant achievement, addressing both the on-site and headquarters officials, Pathak extended heartfelt congratulations to all the dedicated employees of NPCIL who played a crucial role in making this achievement a reality.
BC Pathak expressed the significance of achieving criticality at KAPP-4 within a mere six months of the commercial operation of KAPP-3. In his statement, he emphasised that this accomplishment, coupled with the seamless process of KAPP-3, showcases the robust capabilities of NPCIL across all aspects of nuclear power—from design and construction to commissioning and operation.
Why is this a landmark achievement?
The criticality achievement of KAPP-4 aligns seamlessly with Prime Minister Narendra Modi’s steadfast commitment to India’s net-zero emissions pledge.
Nuclear power, known for its minimal carbon footprint, emerges as a pivotal player in the fight against climate change, steering the nation towards a sustainable future. The significant stride at Kakrapar-4 serves as a reaffirmation of nuclear energy’s crucial role in India’s clean energy roadmap.
The success of KAPP-4 stands as a shining example of India’s burgeoning self-reliance in the nuclear sector. The 700 MW Pressurised Heavy Water Reactor (PHWR) stands as a testament to the proficiency of the Department of Atomic Energy (DAE) and the Nuclear Power Corporation of India Limited (NPCIL). From design and construction to commissioning and operation, the project underscores India’s indigenous prowess in advanced nuclear technology.
Equally commendable is the invaluable contribution of Indian industries and companies in equipping and executing contracts for KAPP-4. This collaborative spirit, propelled by the vision of Atmanirbhar Bharat, is pivotal in driving India’s nuclear energy sector forward.
Having achieved criticality, KAPP-4 now advances towards synchronisation with the grid and initiating clean electricity generation. This not only fortifies India’s energy security but also makes a substantial contribution to its green energy objectives.
The critical milestone of KAPP-4 is more than a triumph for the nuclear power sector; it signifies a monumental achievement in India’s journey towards a sustainable Atmanirbhar future.
