Venkatachari Jagannathan/IANS

Chennai, Jan 29: Indian nuclear scientists will take three steps to improve their experience and expertise before they start on the design of a 1,000 MW fast breeder reactor that will not only generate electricity, but produce more fuel than it consumes.

Building a new 120 MW test reactor powered by metallic fuel, setting up a 500 MW fast breeder reactor having the flexibility to convert to metallic fuel from mixed oxide fuel and changing the existing fast breeder test reactor's (FBTR) core into a metallic core are the steps laid down by the Indira Gandhi Centre for Atomic Research (IGCAR) towards designing a 1,000 MW fast reactor by 2018.

A fast breeder reactor is one which breeds more material for a nuclear fission reaction than it consumes. It is key to India's three-stage nuclear power programme.

The key to designing the 1,000 MW fast reactor is to get things relating to the metallic fuel - a mix of 20 percent plutonium and 80 percent uranium - right as it not only has a high breeding ratio compared to the mixed plutonium-uranium oxide (MOX) fuel but also some technical challenges that needs detailed study.

The MOX fuel will power India's first seven fast reactors including the upcoming 500 MW prototype fast breeder reactor (PFBR) of which one will have the flexibility to convert to metallic fuel.

"The proposed 1,000 MW reactor will be powered by metallic fuel. The first step in realising that is to test the metallic fuel pins and sub-assemblies in the FBTR located at Kalpakkam. This will be followed by replacing FBTR's entire carbide fuel with metallic fuel," Baldev Raj, director of IGCAR, told IANS.

The third step is the construction of the 150 MW test reactor powered by metallic fuel and finally the operation of the dual fuel (MOX and metallic) 500 MW fast reactor.

"The knowledge acquired in designing the oxide fuel fast reactors will be leveraged in building the metallic core reactors. However, the plant parameters will vary between the two reactors which needs detailed study," Reactor Engineering Group Director S.C. Chetal told IANS.

While the new 150 MW metallic fuel test reactor at Kalpakkam, around 80 km from here, is planned during the 12th Five-Year Plan period, the conversion of FBTR to metallic core is expected to happen around 2013.

According to officials two kinds of metallic fuels will be fabricated for testing. While the sodium bonded fuel pins will be designed by IGCAR, the mechanically bonded metallic fuel pins have been developed by Bhabha Atomic Research Centre (BARC) in Mumbai.

Disagreeing that IGCAR is reinventing the wheel in setting up a new test reactor when FBTR will be converted to metallic core and six big fast reactors will be set up, P. Chellapandi, director of safety group, told IANS: "Worldwide there are not many reactors with metallic core. The normal practice is to have a test reactor, then build a medium-sized one and then go for commercial-sized reactors."

"The proposed 150 MW test reactor will be the test bed for metallic fuel. The results will be further validated by using the fuel in the flexible dual fuel fast reactor. The FBTR is a small-sized one and will not give the required data," he added.

According to IGCAR officials, the final design for the six fast reactors - two of which will come up in Kalpakkam - will be released in 2012 or 2013 and the construction will commence in 2017.

"Four fast reactors will be ready by 2020 and the balance two by 2023 - one of which will be the flexible dual fuel reactor," said Chellapandi.

The reactor design work on the ambitious 1,000 MW reactor will be over around 2018 and construction is expected to begin in 2020.