Fast Breeder nuclear reactor at Kalpakam takes ‘critical’ leap forward

Marking a significant step forward in India’s nuclear power programme, Prime Minister Narendra Modi, via a post on X, late on Monday (April 6, 2026), said that the prototype fast breeder reactor (PFBR) at Kalpakkam, Chennai, had achieved ‘criticality.’ This means that the nuclear reaction in the reactor had become safely self-sustaining and was on its way to being able to produce electricity.

“Today India takes a defining step in its civil nuclear journey advancing the second stage of its nuclear programme…the PFBR at Kalpakkam has attained criticality…it is a decisive step towards harnessing our vast thorium reserves,” Mr. Modi posted.