India’s pioneering Fast Breeder Test Reactor (FBTR) at Kalpakkam is set to achieve a major milestone as it completes 40 years of successful operation on October 18, 2025.The reactor, operated by the Indira Gandhi Centre for Atomic Research (IGCAR), first went critical on October 18, 1985. It is a 40 MW thermal / 13.6 MW electrical sodium-cooled fast reactor, using a mixture of plutonium carbide and uranium carbide as fuel — the first of its kind in India’s nuclear programme.
Though no grand celebration is planned, IGCAR is expected to hold a small gathering of current and former Directors to mark the achievement.
The FBTR, which achieved its design power level of 40 MWt on March 7, 2022, began with a smaller 22 Mark-I fuel core rated at 10.5 MWt in 1985. Power levels were gradually increased over the years through innovative core designs and safety upgrades, eventually reaching its full capacity with regulatory clearance from the Atomic Energy Regulatory Board (AERB).
The success of FBTR has laid the foundation for India’s future fast breeder reactor programme, including the upcoming prototype being built at Kalpakkam by Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI).