In a historic milestone for India’s three-stage nuclear power programme, the 500 MWe Prototype Fast Breeder Reactor (PFBR) attained its first criticality on April 6, 2026, at 8:25 PM.
This achievement marks the successful start of a controlled fission chain reaction in the indigenously designed and built reactor, paving the way for enhanced energy security and long-term sustainability.
The criticality was achieved after rigorous safety reviews and clearance from the Atomic Energy Regulatory Board (AERB). The event was witnessed by Dr Ajit Kumar Mohanty, Secretary, Department of Atomic Energy (DAE) and Chairman, Atomic Energy Commission (AEC); Sreekumar G. Pillai, Director, Indira Gandhi Centre for Atomic Research (IGCAR); Allu Ananth, CMD-In-Charge, BHAVINI; and K.V. Suresh Kumar, Former CMD, BHAVINI & Homi Sethna Chair.
Designed and developed by IGCAR under the Department of Atomic Energy, the PFBR was constructed and commissioned by Bharatiya Nabhikiya Vidyut Nigam Ltd (BHAVINI), a Public Sector Undertaking (PSU) of the DAE. The reactor uses Uranium-Plutonium Mixed Oxide (MOX) fuel and features a unique breeding blanket of Uranium-238 that surrounds the core. Fast neutrons convert the fertile Uranium-238 into fissile Plutonium-239, allowing the reactor to “breed” more fuel than it consumes.
A key long-term goal of the PFBR is to eventually utilize India’s vast thorium reserves. The blanket will later incorporate Thorium-232, which will be transmuted into Uranium-233 to fuel the third stage of India’s nuclear programme. This capability significantly multiplies the energy extractable from limited uranium resources and positions India to harness its abundant thorium for future clean power generation.
Fast Breeder Reactors form the critical second stage of India’s nuclear strategy, bridging the current Pressurized Heavy Water Reactors (PHWRs) and the upcoming thorium-based reactors. The technology incorporates advanced safety systems, liquid sodium coolant, and a closed fuel cycle that enables recycling of nuclear materials, thereby improving fuel efficiency and minimising waste.
The achievement underscores India’s growing prowess in indigenous nuclear technology, advanced materials, reactor physics, and large-scale engineering. It reflects the collective efforts of thousands of scientists, engineers, technicians, and industry partners who contributed to the project under the vision of Atmanirbhar Bharat.
With this milestone, India moves closer to realising the full potential of its three-stage nuclear programme, strengthening its commitment to reliable, low-carbon base-load power and technological self-reliance for a Viksit Bharat.
