Clean-up soon? Seized containers with radioactive material in Delhi

New Delhi, Jan. 10: An Indian-American physicist has initiated a joint study with India’s department of atomic energy (DAE) to assess his new technology that may significantly reduce hazardous waste churned out by nuclear reactors.

The DAE has indicated that it will launch later this year pencil-and-paper studies to assess the relevance of the technology that may also help accelerate India’s pace towards harnessing the country’s abundant reserves of thorium for nuclear power production.

Swadesh Mahajan, a senior scientist at the Institute of Fusion Studies at the University of Texas and his colleagues have proposed a compact nuclear fusion device that could help virtually eliminate the long-lived radioactive waste produced in nuclear fission reactors that otherwise remain toxic for tens of thousands of years. The physicists believe such a fusion-fission hybrid may also be useful to breed uranium fuel from thorium.

“We believe this fusion-fission hybrid is a worthy suitor for a highly coveted bride — India’s nuclear power programme,” said Mahajan.

The technology uses subatomic particles called neutrons produced during nuclear fusion to drive nuclear fission which, Mahajan said, is a “very mature, very successful, and very-well understood commercial technology”.

“It will address two serious problems associated with fission — nuclear waste and the shortage of fissile materials in nature that can be used as nuclear fuel,” Mahajan said.

In a fusion-fission hybrid tailored to breed nuclear fuel, a compact fusion source will be positioned at the core of a reactor surrounded by a blanket of thorium. The neutrons will transform thorium into uranium, which can serve as a nuclear fuel.

A scientist from the Bhabha Atomic Research Centre (BAARC), Mumbai, is likely to visit Mahajan’s laboratory and examine whether the fusion-fission hybrid could find use in India’s nuclear power programme.

“His group has an interesting architectural plan — we’d like to use our strengths in reactor physics and engineering and the nuclear fuels to assess whether it can fit in with our goals,” said Vinod Sahni, a senior physicist and a DAE Homi Bhabha Chair professor at the BARC. “If there are no major bugs in being able to implement this idea, we could start thinking about this as a potential technology,” Sahni told The Telegraph.

Research groups at Princeton University and the UK also plan to study the proposal. Senior physicists caution that this is a futuristic technology whose engineering requirements and economic implications still need to be analysed.

The fusion-fission hybrid will provide abundant neutrons to a surrounding fission blanket that uses waste products from nuclear reactors as nuclear fuel. Such incineration of nuclear sludge would itself be used to generate nuclear electricity.

The waste currently generated by nuclear power is reprocessed but eventually the long-lived radioactive waste will need to be stored in deep geological repositories. “It might be difficult to find such sites in countries such as India with high populations,” Mahajan said.

A single hybrid reactor could destroy waste from up to 10 conventional fission reactors. Mahajan and his colleagues Prashant Valanju and Mike Kotschenreuther estimate that the process might be able to reduce waste from fission reactors by up to 99 per cent.

While several countries including India are pursuing experiments aimed at generating technologies for viable power through nuclear fusion, scientists say it is still too early to even predict when this will become possible.

In nuclear fusion — where two nuclei come together to release energy — the extreme high temperatures of more than 100 million°C generated require long-lasting materials which are yet to be developed. “We have no materials that can tolerate such conditions for even 10 years,” Mahajan said.