At 20:26 hrs on Apr 6, 2026, India's most advanced nuclear reactor came to life
At 20:26 hrs on Apr 6, 2026, India's most advanced nuclear reactor came to life Photograph: (WION)
India’s 3-stage nuclear programme is a sequential strategy to convert uranium into plutonium and finally utilise thorium for generating sustainable nuclear energy.
20:26 hours, April 6th, 2026, is a moment that will remain etched in national history, as India's 500 Megawatt Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, Tamil Nadu, successfully attained first criticality, which is the start of a controlled fission chain reaction.
This marked India's long-awaited foray into the second stage of its three-stage Nuclear power programme. Envisioned in 1954 by eminent physicist Homi Jehangir Bhabha, India's three-stage Nuclear power programme is aimed at achieving energy security using the country's limited Uranium and vast Thorium reserves.
A reactor going critical is the culmination of a long process; the PFBR has been in the works for more than two decades. Usually, there is a gap of several months between fuel being loaded into a nuclear reactor and the reactor going critical. During the months after fuel loading, a series of engineering and physics tests are carried out to validate a host of parameters. While criticality is a major step in the commencement of operations at a nuclear power plant, it does not mean that it has begun generating power at its full potential. Power generation is ramped up gradually in a phased manner.
The technology development and design of PFBR was indigenously done by the Indira Gandhi Centre for Atomic Research (IGCAR), an R&D Centre of the Indian Government's Department of Atomic Energy. The PFBR was built and commissioned by Bharatiya Nabhikiya Vidyut Nigam Ltd (BHAVINI), a Government firm. India's top Nuclear sector officials were present as the reactor went critical: Dr Ajit Kumar Mohanty, Secretary, Dept of Atomic Energy & Chairman, Atomic Energy Commission; Sreekumar G Pillai, Director, IGCAR; Allu Ananth, CMD-In-Charge, BHAVINI.
What is India's three-stage nuclear programme?
India’s 3-stage nuclear programme is a sequential strategy to convert uranium into plutonium and finally utilise thorium for generating sustainable nuclear energy.
In the first stage, Pressurised Heavy Water Reactors (PHWRs) use natural Uranium to generate electricity and produce Plutonium-239 as a by-product. At present, India has about two dozen PHWR Nuclear power plants, which contribute about 3percent of India's total power generation.
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The second stage employs Fast Breeder Reactors (FBRs), which use Plutonium(by-product from the first stage) to generate more fissile material, while converting thorium into Uranium-233.
In the third stage, advanced reactors utilise Uranium-233 along with Thorium to produce sustainable nuclear energy.
In simple terms, India's Fast Breeder Reactors technology forms the vital bridge between the current fleet of pressurised heavy water reactors and the future deployment of Thorium-based reactors.
This long-term strategy is particularly suited to India, which possesses minimal Uranium reserves but one of the world’s largest Thorium reserves. While the first stage is fully operational, the second stage has just begun and has a long way to go, while the third stage remains in the research phase.
India's goal to expand nuclear power generation capacity
At present, India has the capacity to generate about 8,780 megawatts of Nuclear energy from over two dozen facilities across the country. India's Nuclear power generation capacity is expected to increase to 22,380 MW by 2031-32 on progressive completion of projects under implementation, as per Government data. Thus, over the next decade, nuclear power generation is expected to increase threefold.
