Desk Correspondent , Chennai - India's first indigenous Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, Tamil Nadu, has successfully attained criticality on April 6, 2026, marking the formal launch of the second stage of the country's three stage nuclear power programme. The 500 MWe reactor, developed by BHAVINI under the Indira Gandhi Centre for Atomic Research (IGCAR), achieved a self-sustaining nuclear chain reaction at 20:26 hrs, a historic step toward energy security using fast breeder technology. Prime Minister Narendra Modi hailed it as a "defining step" reflecting India's scientific prowess.

The PFBR uses plutonium uranium mixed oxide (MOX) fuel and liquid sodium as coolant, breeding more fissile material than it consumes to multiply uranium resources a key feature for India's limited uranium reserves but vast thorium deposits. This second stage milestone builds on the first stage's Pressurised Heavy Water Reactors (PHWRs), paving the way for Stage III thorium based Advanced Heavy Water Reactors (AHWRs) and long-term self-sufficiency. After low-power physics experiments, the reactor will ramp up to full operation, generating 500 MW while minimising nuclear waste through a closed fuel cycle.

Clearance from the Atomic Energy Regulatory Board (AERB) followed years of fuel loading and testing, overcoming first of a kind challenges. Once commissioned, India will join Russia as one of few nations with commercial fast breeder capability, boosting indigenous tech and thorium utilisation for sustainable power. The achievement strengthens India's nuclear ambitions amid global energy transitions.