India’s PFBR Reactor Achieves Criticality Milestone

India has reached a major milestone in its civil nuclear energy programme as the Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, Tamil Nadu, attained criticality. This marks the initiation of a self-sustaining nuclear fission chain reaction, a crucial step before full-scale power generation. The development signifies India’s advancement into the second stage of its three-stage nuclear power programme.

What Criticality Means in Nuclear Reactors

Criticality refers to the stage where a nuclear reactor sustains a stable chain reaction without external neutron input. At this point, each fission event releases enough neutrons to maintain the reaction continuously. Although criticality does not imply full electricity generation, it is a key milestone in reactor commissioning and safety validation.

Features of the Prototype Fast Breeder Reactor

The PFBR is a 500 megawatt electric sodium-cooled fast breeder reactor developed indigenously over more than two decades. It is operated by Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI) at the Indira Gandhi Centre for Atomic Research (IGCAR). Unlike conventional reactors, PFBR uses plutonium-based fuel and is designed to produce more fissile material than it consumes, enhancing fuel efficiency.

Role in India’s Three-Stage Nuclear Programme

The PFBR marks India’s entry into the second stage of the nuclear programme envisioned by Dr. Homi Jehangir Bhabha. In this stage, plutonium derived from Pressurised Heavy Water Reactors is utilised in fast breeder reactors. This process enables the eventual transition to the third stage, which focuses on thorium-based reactors, leveraging India’s vast thorium reserves.

Important Facts for Exams

• PFBR is located at Kalpakkam in Tamil Nadu.
• Fast breeder reactors produce more fissile fuel than they consume.
• India’s nuclear programme follows a three-stage strategy.
• Thorium reserves in India are among the largest globally.

Strategic and Energy Security Implications

The achievement strengthens India’s long-term energy security and supports its clean energy goals, including net zero emissions by 2070. Fast breeder technology allows efficient recycling of nuclear fuel and reduces dependency on imported uranium. Once fully operational, the PFBR is expected to serve as a model for future reactors and significantly contribute to India’s plan of expanding nuclear power capacity to 100 gigawatts by 2047.