Ministers gamble on new £6bn Sellafield plant

The Government is preparing to announce the construction of a new multi-billion pound nuclear fuel plant at Sellafield just weeks after an identical facility had to be closed because it was unfit for purpose.

Officials have advised ministers to reject a "third way" of dealing with Britain's civil plutonium stockpile – the biggest in the world – and forge ahead with a second mixed oxide (Mox) fuel plant at Sellafield costing up to £6bn.

Independent scientists have suggested that instead of building an expensive new Mox plant to deal with the plutonium stockpile, Sellafield could use its existing plant to make inexpensive, low-grade Mox fuel that could be buried underground rather than being burned in nuclear reactors.

However, it is understood that ministers have been advised that this option is unviable, which leaves them a choice of either encasing the plutonium in ceramic blocks for burial as high-level waste, or gambling on yet another Mox plant costing £3bn to build with lifetime costs nearer £6bn.

The impending decision follows the report of the nuclear chief inspector, Mike Weightman, into lessons from the Fukushima disaster in Japan which will say that there is no need to cancel the decision to launch a major nuclear rebuild programme in Britain – despite the problem of waste plutonium still being unresolved.

Sellafield unions and politicians in Cumbria have lobbied for a second Mox plant to save the 1,000 jobs that could be lost with the closure of the existing £1.3bn Sellafield Mox Plant. However, the possibility of keeping the plant open in order to make low-grade "disposable" Mox has been ruled out.

The Nuclear Decommissioning Authority, which is in charge of Sellafield, has rejected the disposable Mox option, arguing that the existing Mox plant cannot even make enough low-grade fuel. It also says that the plutonium in disposable Mox could still be used for making weapons as it would not have been irradiated when used as fuel in a nuclear reactor.

But an ex-senior scientific adviser to the White House has criticised the UK's decision to reject disposable Mox as a third option, saying low-grade fuel could be readily manufactured in the existing Sellafield Mox Plant at low cost and with no need to build nuclear reactors specifically to burn Mox fuel.

Professor Frank von Hippel of Princeton University co-authored a report on disposable Mox as a "third way" for plutonium disposal, which he offered to send to Department for Environment and Climate Change (DECC) officials as part of the UK Government's plutonium consultation. He did not receive any reply to his initial emails to the DECC offering assistance.

"It would be interesting to see the analysis by which the DECC has concluded that it would be less costly to build a new £3bn MOX plant than extend the life of the existing Sellafield MOX Plant," he said.

A DECC spokesman said that the professor's comments were taken into account when the Government prepared its consultation paper on plutonium, which said that the manufacture of low-specification Mox would still require a new Mox plant at Sellafield.

"Even with the removal of [the Sellafield Mox Plant's] existing commitments it still would not have a high enough throughput to deal with all plutonium either as MOX fuel or MOX for disposal," the DECC spokesman said.