India Reaches Milestone in Nuclear Power: Kalpakkam Fast Breeder Reactor Attains Criticality
New Delhi, April 6, 2026 — India has officially achieved a monumental breakthrough in its quest for energy independence and advanced nuclear technology. Prime Minister Narendra Modi announced on Monday that the country’s first indigenously designed and built Prototype Fast Breeder Reactor (PFBR), located at Kalpakkam in Tamil Nadu, has successfully attained criticality.
This major milestone marks the operationalization of the crucial second stage of India’s ambitious three-stage nuclear power programme.
A “Defining Step” for India’s Nuclear Journey
Taking to the social media platform X (formerly Twitter), Prime Minister Modi congratulated the scientific community and engineers for the achievement.
“Today, India takes a defining step in its civil nuclear journey, advancing the second stage of its nuclear programme,” PM Modi wrote. He confirmed that the indigenous reactor had attained criticality and praised the ingenuity behind the project.
“This advanced reactor, capable of producing more fuel than it consumes, reflects the depth of our scientific capability and the strength of our engineering enterprise,” the Prime Minister stated, adding that it is a “proud moment for India”.
Today, India takes a defining step in its civil nuclear journey, advancing the second stage of its nuclear programme.
The indigenously designed and built Prototype Fast Breeder Reactor at Kalpakkam has attained criticality.
This advanced reactor, capable of producing more fuel…
— Narendra Modi (@narendramodi) April 6, 2026
What is the Fast Breeder Reactor?
The 500 MWe Prototype Fast Breeder Reactor is a massive achievement in self-reliance, developed by the Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI) and designed by the Indira Gandhi Centre for Atomic Research (IGCAR).
The reactor earns the name “breeder” because it is designed to generate, or “breed,” more nuclear fuel than it actually consumes during its operation. By utilizing high-energy neutrons, the reactor can convert abundant, non-fissile materials into usable nuclear fuel. The state-of-the-art facility runs on a mixed oxide (MOX) fuel composed of Uranium and Plutonium, and it specifically uses liquid sodium as its coolant.
Stepping Stone to Thorium
The successful criticality of the PFBR is not just a standalone achievement; it is a vital bridge to India’s energy future. The reactor forms the foundation for the eventual third stage of the nation’s nuclear programme, which aims to fully utilize India’s massive, naturally occurring reserves of Thorium.
“It is a decisive step towards harnessing our vast thorium reserves in the third stage of the programme,” PM Modi highlighted in his message.
By successfully attaining criticality—a state where the nuclear chain reaction becomes safely self-sustaining—the Kalpakkam reactor will eventually be linked to the electrical grid to commence commercial power generation. This major technological breakthrough solidifies India’s position as one of the few nations worldwide capable of managing a closed nuclear fuel cycle, paving the way for drastic reductions in radioactive waste and securing long-term, clean baseload energy for the nation.