India needs to import uranium only as a "stop gap" measure until its own thorium fuelled reactors come on stream, Bhabha Atomic research Centre (BARC) director Sreekumar Banerjee has clarified.

"We need to import uranium only for couple of decades by which time we would be able to build thorium fuelled reactors," Banerjee said after delivering the 22nd lecture in memory of Brahm Prakash, the renowned metallurgist, at the Indian Institute of Science here Monday evening.

Banerjee was trying to allay fears that the impending deal with the United States might make the country’s power programme perpetually dependent on imported uranium or halt thorium development on its tracks.

He said the India-US deal would not lead to India abandoning the three-stage nuclear programme envisioned by Homi Bhabha, the architect of the country’s nuclear programme.

Bhabha’s dream was to eventually produce electricity by utilizing the abundant thorium in India’s beach sands. India’s thorium accounts for one-third of the total world reserves while its uranium reserves are just enough to generate 10,000 MW – less than one per cent of India’s current installed capacity.

Banerjee said India cannot afford to anchor its entire nuclear power programme on imported uranium as it would be economically risky. He said cost of nuclear power could increase if uranium price shot up like petroleum crude. For this reason he said, India cannot give up the three-stage programme.

The programme involves building natural uranium fuelled reactors in the first phase and use the by-product plutonium from these reactors in fast breeder reactors (FBRs) in the second phase. The FBRs will — apart from generating electricity — turn "fertile" thorium into "fissile" Uranium-233. Once sufficient inventory of U-233 is built up, reactors in the third phase will be built entirely using U-233 and Thorium.

According to Banerjee, the Indo-US deal, that will enable India acquire uranium from international market, will help to "bridge the gap" between phase-1 and phase-3.

Banerjee said BARC has already started to address the issues relating to thorium utilization. He said funding for thorium reactor development will start once the economic viability of such reactor systems is assessed.