Indian regulator approves FBR fuel loading

Phased core loading activities began earlier this year, with the insertion of control sub-assemblies and blanket sub-assemblies under AERB oversight. The regulator said its approval of the First Approach to Criticality follows a review process which included those activities, execution of a thorough multi-tier safety review, regular inspections and oversight by a resident site observer team.

"Following extensive evaluation of the detailed safety submissions, review outcomes, and a site visit, the Board has affirmed the systematic regulatory oversight and granted the necessary permissions," the AERB said in a statement dated 27 July and published on 30 July.

Now that permission has been granted for the First Approach to Criticality, fuel sub-assemblies will be introduced into the reactor core. Once a sustained nuclear fission chain reaction is achieved, marking the reactor's criticality, a series of low power physics experiments will be conducted to further assess and understand reactor behaviour, the AERB said.

Fast breeder reactors form the second stage of India's three-stage nuclear programme, using plutonium recovered from the reprocessing of used fuel from the pressurised heavy waters and light water reactors that form the first stage of the programme. The third stage envisages using advanced heavy water reactors (AHWRs) to burn thorium-plutonium fuels and breed fissile uranium-233, achieving a thorium-based closed nuclear fuel cycle.

The PFBR has been developed by BHAVINI (Bharatiya Nabhikiya Vidyut Nigam Limited), a government enterprise under the Department of Atomic Energy. Construction began in 2004, with an original expected completion date of 2010. It will initially use a core of uranium-plutonium mixed oxide (MOX) fuel, surrounded by a uranium-238 'blanket', with plans to use a blanket of uranium and thorium to breed plutonium and uranium-233 for use as driver fuels for AHWRs.

Indian Prime Minister Narendra Modi witnessed the start of the phased core loading activities at the reactor, which is in Tamil Nadu, in March.