The government has been urged to reassess its approach to dealing with the country’s huge plutonium stockpile.
A new policy statement from the Institution of Mechanical Engineers calls for the UK to adopt a portfolio of options to address the different types of plutonium stored in the UK, and highlights the urgent need for the Nuclear Decommissioning Authority (NDA) to categorise these stocks.
The IMechE said the government should also consider using ‘fast reactors’ like those in development by GE Hitachi in the US and the Astrid project in France.
“There are estimates that it currently costs the UK taxpayer £80 million a year to safely store the country’s 112 tonnes of civil held plutonium,” said Dr Tim Fox, Head of Energy and Environment at the IMechE.
“In addition to costs, this material is highly toxic, radioactive and can be used to develop nuclear weapons, so dealing with it safely and securely is of critical importance to the nation's security.
“As we move forward in this country towards building new reactors, this becomes ever more urgent."
Dr Fox said the government’s current plan for dealing with the stockpile by focussing on finding a single solution was too limited, likely to be costly to the taxpayer, and risked issues of nuclear proliferation.
He said the government should treat the different grades of plutonium in the stockpile in different ways, and that the NDA urgently needed to start work on categorising and quantifying this material.
“For the part of the stockpile that is of the right grade the government should consider using it as fuel for ‘fast reactors’ like those being developed commercially by GE Hitachi in the US and by the Astrid project in France," he said.
“A fast reactor of this nature would help deal with a proportion of this material, effectively recycling the stockpile while generating low-carbon electricity.
“This type of reactor would make a small but useful contribution to UK energy security and it has been estimated that doing this could potentially generate £15 billion in its 60-year lifetime.”
The government’s preferred option is to combine plutonium stocks with uranium to make a Mixed Oxide (MOX) fuel, which could then be exported, but the IMechE said the market for this is limited and others have similar ambitions.
After use in conventional nuclear reactors, MOX leaves spent fuel in a state where the remaining plutonium is inaccessible but it will still need to be prepared for permanent geological disposal.
The IMechE proposes that once the NDA categorises plutonium stocks:
• High-grade plutonium should be considered for manufacture into MOX fuel.
• Lower-grade plutonium should be identified for potential recycling in a fast reactor. The government, through the NDA, should fund modest assessment and development of the available fast reactor technologies; at this stage future licensing decisions cannot be prejudged, but the sodium-cooled fast reactor route is sufficiently attractive to merit significant immediate UK support.
• Poor-quality material should be earmarked for safe disposal, with investment required.
The UK’s plutonium stockpile is largely the result of the country’s early nuclear programme, when plutonium was previously seen as a fuel for future power production.
Plans also included the UK taking spent fuel from overseas reactors for reprocessing and then selling it back to its country of origin for a fee; the stockpile includes about 28 tonnes of material belonging to overseas customers. However this did not occur.