Towards Self-Sufficiency in Nuclear Energy
On April 6, 2026, India achieved a landmark milestone in nuclear energy by achieving first criticality at the 500 MWe Prototype Fast Breeder Reactor (PFBR) in Kalpakkam, Tamil Nadu. Developed by BHAVINI and the Indira Gandhi Centre for Atomic Research (IGCAR), this indigenous reactor marks the start of the second stage of India’s three-stage nuclear programme
India is now only the second country, after Russia, to have a commercial-level fast breeder reactor.
This success supports the second stage of India’s nuclear energy policy, essential for long-term energy security and a sustainable “Atmanirbhar Bharat” (self-reliant India).
India’s three-stage nuclear programme, formulated by Homi J. Bhabha in the 1950s, aims to secure long-term energy independence by utilizing the country’s limited uranium and vast thorium reserves through a closed fuel cycle. The stages are: 1) Pressurised Heavy Water Reactors (PHWRs) using natural uranium, 2) Fast Breeder Reactors (FBRs) utilizing plutonium, and 3) Advanced thorium-based reactors.
The criticality on April 6 at Kalppakam was achieved in the presence of Dr Ajit Kumar Mohanty, Secretary, DAE & Chairman, AEC, Shri Sreekumar. G. Pillai, Director, IGCAR, Shri Allu Ananth, CMD-In-Charge, BHAVINI, and Shri K.V. Suresh Kumar, Former CMD, BHAVINI & Homi Sethna Chair after meeting all the stipulations of the Atomic Energy Regulatory Board (AERB), which had issued clearance after a rigorous review of the safety of the plant systems.
The technology development & design of PFBR was indigenously done by Indira Gandhi Centre for Atomic Research (IGCAR), an R&D Centre of the Department of Atomic Energy, and was built & commissioned by Bharatiya Nabhikiya Vidyut Nigam Ltd (BHAVINI), a PSU under the Department of Atomic Energy.
Fast Breeder Reactors are a cornerstone of India’s long-term nuclear strategy. Unlike conventional thermal reactors, the PFBR uses Uranium-Plutonium Mixed Oxide (MOX) fuel. The core of PFBR is surrounded by a blanket of Uranium-238. Fast neutrons convert fertile Uranium-238 into fissile Plutonium-239, enabling the reactor to produce more fuel than it consumes. The reactor is eventually designed to use Thorium-232 in the blanket. Through transmutation, Thorium-232 will be converted into Uranium-233, which will fuel the third stage of India’s nuclear power programme.
This unique capability significantly enhances the utilization of nuclear fuel resources and enables the country to extract far greater energy from its limited uranium reserves while also preparing for large-scale use of thorium in the future.
With the achievement of first criticality, India moves closer to realizing the full potential of its three-stage nuclear power programme. Fast breeder technology forms the vital bridge between the current fleet of pressurized heavy water reactors and the future deployment of thorium-based reactors, leveraging the country’s abundant thorium resources for long-term clean energy generation.
The latest achievement is all the more significant because India has little uranium, which is an essential fuel for nuclear reactors. However, the self-sustaining technology will help India use thorium. The country has some of the world’s largest thorium reserves, found on the sandy shores of Odisha, Kerala, and Andhra Pradesh.
The Kalpakkam reactor beautifully blends the two realities of little uranium and abundant thorium reserves. The reactor, powered by uranium in the first stage, can be sustained by thorium-blended fuel in the later stages. This will end India’s dependency on uranium imports.
The reactors at Kalpakkam can produce more nuclear fuel than they consume. They can also help India eventually tap thorium to power the country for centuries. That makes it a strategic win as much as a scientific one.
Achieving this milestone demonstrates the strength of India’s indigenous design, engineering and manufacturing ecosystem. In fact, India has pulled off what some of the world’s biggest nuclear powers — the United States and France — could not, despite pumping in billions of dollars.
China is still taking baby steps to operationalise the technology at a commercial scale. China only has the small experimental CEFR reactor and the CFR-600 prototype.
The reactor incorporates advanced safety systems, high-temperature liquid sodium coolant technology and a closed fuel cycle approach that enables recycling of nuclear materials, thereby improving sustainability and reducing waste.
As India continues to expand its clean energy portfolio, fast breeder reactors will play a crucial role in delivering reliable, low-carbon, base-load power with higher thermal efficiency. The attainment of first criticality represents not only a technological milestone but also a major step towards a sustainable and self-reliant energy future for Viksit Bharat.
