Chennai, Apr 30 (IANS): The 500 MW prototype fast breeder reactor (PFBR) at Kalpakkam will soon get its first lot of fuel assemblies - used to build its nuclear fuel core, a senior official has said, adding that 86 percent of the "physical work" on the plant has been completed.

The Rs.5,677 crore project is being built by India's fast breeder reactor operator Bharatiya Nabhikiya Vidyut Nigam Ltd (Bhavini). Kalpakkam is 80 km from Chennai.

"We will soon start getting the fuel assemblies in several lots from Bhabha Atomic Research Centre (BARC) while welding of blanket fuel assemblies was flagged off by Atomic Energy Commission chairman (Srikumar Banerjee) Saturday here," Prabhat Kumar, director (construction) and project director, told IANS.

The finished fuel rods are grouped in special fuel assemblies that are then used to build up the nuclear fuel core of a power reactor.

About the project status, Kumar said 86 percent of the physical work has been completed and by the end of this year all the mechanical work would be completed.

The reactor is wholly designed by Indira Gandhi Centre for Atomic Research (IGCAR) located at Kalpakkam.

The fast breeder reactor, which breeds more material for a nuclear fission reaction than it consumes, is one of the key projects of India's three-stage nuclear power programme. In 1985, India became the sixth country to have such a technology.

The supply of fuel assemblies for PFBR signals the comfortable position of Indian nuclear establishment with regard to the availability of uranium to run the atomic power reactors.

According to Kumar, the PFBR will have 181 fuel assemblies and 120 blanket assemblies.

The PFBR will be powered by a mix of plutonium oxide and depleted uranium oxide called MOX fuel.

"Blanket assemblies contain depleted uranium to absorb the excess neutrons that are generated from the nuclear fission that happens at the reactor core. After a few years, the blanket assemblies are reprocessed to extract plutonium for the initial feed of future fast reactors," P.Chellapandi, director, Nuclear Design and Safety at IGCAR, told IANS.

While the fuel assemblies will be placed at the centre of the reactor vessel, the blanket assemblies will be kept surrounding the former, Chellapandi added.

Kumar said the dummy fuel (fuel similar to the real one in terms of specifications minus the fission material) is expected in couple of month's time.

"This is the first of its kind reactor for India. We want to be sure about every aspect of the reactor before taking it to criticality. The fuel loading will be done only when we are very sure about the reactor performance and safety," Kumar said.

He said the project capex would not exceed Rs.5,677 crore but there will be some sizeable savings.

"A total of Rs.3,800 crore has been spent so far on the project," Kumar said.