'Untested' nuclear reactors may be used to burn up plutonium waste

Feasibility study looks at building revolutionary new facility at Sellafield to dispose of stockpile

An ambitious plan to rid Britain of its civil plutonium stockpile – the biggest in the world – has come a step closer with the submission of a feasibility study for building revolutionary nuclear reactors to "burn" the waste at Sellafield in Cumbria.

The plan envisages the construction of twin nuclear "fast reactors" at Sellafield that can dispose of the plutonium directly as fuel to generate electricity while ridding the country of a nuclear-waste headache that has dogged governments for half a century.

Britain's Nuclear Decommissioning Authority (NDA), which is in overall charge of Sellafield, requested the study last year in a remarkable U-turn in its stated policy of dealing with the 112 tonnes of civil plutonium that has accumulated as a result of the reprocessing of spent nuclear fuel.

Critics say that fast reactors are still at the research stage of development and are not yet ready to be deployed for such a critical task.

The American company behind the proposal, GE Hitachi Nuclear Energy, still has a long way to go to convince experts that it can deliver reactors that can work as promised, as well as being delivered on time and to budget. The NDA has consistently said that its "preferred option" to deal with the plutonium waste is to first convert it to mixed oxide (Mox) fuel and then burn it in conventional, pressurised-water reactors. However, the authority is keeping other "credible options" open, including fast reactors.

GE Hitachi said it had received US government approval to export its fast-reactor technology and could build the twin reactors without incurring upfront costs to the British taxpayer, which would be hugely popular with the UK Government.

The company emphasised in its submission that it is based on technology that has operated successfully for 30 years in the US in an experimental facility.

The feasibility study is now being reviewed by the NDA and a decision on whether to proceed to the next stage of the process will be made later this year.

A spokesman for the authority said: "NDA has previously stated that fast reactors, such as Prism, have been screened out as not credible at this time. It was not considered that they would be commercially available for several decades," he said. "Though the technology was well developed at the research reactor stage, the supply chain has yet to give indication of any substantive commercial development of these systems in the short-to-medium term. At this time, NDA believe that this is still the case. However, we are considering the recent proposal from GE Hitachi to assess its credibility."

Britain's previous attempts to convert plutonium into Mox fuel which could then be burned in conventional reactors have proved disastrous, culminating in the premature closure last year of the £1.34bn Sellafield Mox Plant, which was a commercial and technical failure. Despite the debacle over Mox fuel, however, the NDA and officials with the Department for Energy and Climate Change have advised the Government to build a second Mox fuel plant, for an estimated cost of £3bn, as a way of dealing with the plutonium problem.

This plan would involve the French nuclear company Areva, which is also involved in building a similar Mox operation in the US to deal with its military plutonium stockpile. However, this troubled plan is 11 years behind schedule and between six and 10 times over budget.

Britain's nuclear future: The options

* Convert the plutonium waste into mixed oxide (Mox) fuel and then burn the fuel in conventional, pressurised-water reactors. This would involve the construction of a second Mox fuel plant at Sellafield, at a cost of at least £3bn. Past experience suggests it could turn out to be an expensive failure and it would still involve new reactors licensed to burn the Mox fuel. A variation on this idea is to burn the Mox fuel in the Candu nuclear reactors of Canada.

* Dispose of the plutonium directly by burning it in the Prism fast reactors of GE Hitachi. Critics say the technology is not mature enough and would involve taking bigger risks than converting the plutonium into Mox fuel. GE Hitachi promises to build the twin fast reactors without any public subsidies and will charge the UK Government only for the amount of plutonium processed. Nuclear authorities are now studying the feasibility of such a radical solution.

* Convert the plutonium-oxide powder now in short-term storage at Sellafield into ceramic blocks that can be buried deep underground for thousands of years. This had been ruled out by nuclear authorities but is supported by some academics and the environmental movement, who argue that the alternatives are too risky and unproven. An underground repository will have to be built for other high-level nuclear waste, so burying the plutonium is credible, they argue.