
New Delhi : India’s nuclear energy programme took a giant step forward as its long awaited fast breeder reactor finally reached criticality. The development is being closely watched by scientists, policymakers, and energy experts alike because of what it could mean for the country’s long term energy future.
In a landmark achievement for India's nuclear energy programme, the 500 MWe Prototype Fast Breeder Reactor (PFBR) has successfully attained first criticality (start of controlled fission chain reaction) on 6th April 2026 at 08:25 PM marking a historic step in providing long-term energy security and advancing indigenous nuclear technology capabilities, according to the Department of Atomic Energy.
The criticality was achieved in the presence of Dr Ajit Kumar Mohanty, Secretary, DAE & Chairman, AEC, Sreekumar G Pillai, Director, IGCAR, Allu Ananth, CMD-In-Charge, BHAVINI and KV 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 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 designed to eventually 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 utilisation 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.
Fast breeder technology forms the vital bridge between the current fleet of pressurised heavy water reactors and the future deployment of thorium-based reactors, leveraging the country's abundant thorium resources for long-term clean energy generation.
Achieving this milestone demonstrates the strength of India's indigenous design, engineering and manufacturing ecosystem. 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.
For India, this matters more than it might for other countries. The country has relatively modest reserves of high grade uranium but vast deposits of thorium. Decades ago, nuclear physicist Homi J. Bhabha laid out a three stage programme that would eventually allow India to tap into its thorium reserves for energy. Fast breeder reactors form the crucial second stage of that plan, producing the materials needed to make the transition possible.