UK Plutonium, CANDU with CANMOX?

Dr Tim Fox considers an interesting proposal for using the UK plutonium stock pile to generate low-carbon electricity, create jobs and deliver economic benefits.

You may remember that two years ago in March 2013 we published a Policy Statement on the potential routes to UK plutonium disposition, UK Plutonium: The Way Forward.

At that time the UK was storing 112 tonnes of civil held plutonium and the Government was beginning to reassess options for its future management.

The Institution recommended that the government "adopts a portfolio of options" to address these stocks recognising that a range of solutions was potentially required; not all the plutonium in the UK stockpile is equal in terms of its isotopic mix or chemical contamination, and therefore one single option was not in our opinion the best approach.

However, recognising that plutonium can be a valuable potential source of energy with low carbon emissions, the manufacture of mixed oxide (MOX) fuel for use in conventional nuclear power reactors as well as recycling in fast reactors was considered, alongside geological disposal.

As at the time we saw no clear or obvious front runners, we concluded that all of these routes might be required and should be evaluated further.

Since then I have kept a watching brief on the developments for UK plutonium disposition, and there is now an interesting option emerging which builds on our suite of March 2013 solutions.

John Earp, who sits on the Nuclear Power Committee at the Institution, and myself have been involved recently in an initial assessment of the CANMOX solution, which utilises the successful Canadian CANDU reactor design, and it appears from an engineering perspective to be an attractive option worthy of further consideration.

Candu Energy Inc. is a Canadian company, currently supplying approximately 50 per cent of Ontario’s electricity and 16 per cent of Canada’s overall electricity requirements. Internationally, they play a not insignificant part in the nuclear energy sector with over 22,000 megawatts of installed capacity across four continents. 

In the case of the UK plutonium stockpile, they propose to turn the material into (MOX) fuel at a dedicated fabrication facility to be based at Sellafield and this would then be used in a suite of four Enhanced CANDU 6 (EC6) reactors to produce around 3GW(e) of power for commercial sale in the reformed UK electricity market.

Due to space constraints at the Sellafield site these new nuclear plants would be located at already licenced sites that have rail access to facilitate the safe transfer of fuel by conventional means.

There are two significant engineering observations regarding this proposed solution:

• Firstly, this builds on a proven technology. There are 47 CANDU and "CANDU-type" reactors up and running globally, the EC6 variation is Canadian Pre-Project Design Approved and the MOX fuel has already been demonstrated in testing. Candu Energy also has a robust track record of on-schedule and on-budget delivery of nuclear new-build projects worldwide.
• Secondly, Candu Energy expects to be able to complete UK plutonium disposition within 30 years, regardless of the grade and contamination, through a single solution rather than the potential raft of options that the Institution had previously considered necessary. Additionally their proposed solution would make a useful contribution to UK energy security, as well as create skilled employment opportunities and economic benefits through an 80% localisation target.

Candu have been working hard with the Nuclear Decommissioning Authority (NDA) in the UK and DECC to understand the complexities of the UK market. There is clearly a common purpose between the different parties, and we might expect announcements about ongoing collaboration and further exploration of the option in the near future.  

On the 16/17th March, Candu are hosting a seminar here at One Birdcage Walk CANMOX: A Utility Proven Solution for Management of the UK’s Civil Plutonium Stockpile to celebrate UK-Canadian partnerships on nuclear technology. The event will be a great opportunity to get a deeper understanding of CANDU technology, its potential for deployment in the UK and the strategic benefits to the UK fuel cycle. It will be repeated on 18-19 March at the University of Manchester. 

It is always exciting to see a well thought through engineering option, which has effectively been developed ‘under the radar', emerge as a genuinely promising solution to a technically challenging problem.

Questions I often ask in such circumstances include: Will it lead to surprising and previously unexpected opportunities for the development of UK engineering skills and export markets? Will it drive innovation across the sector and prompt renewed activity on other potential solution routes? Will it convince the Government to take action and encourage development and deployment? Post-election, when decisions will be made, I urge you to watch this space closely to see if CANMOX can do.

Dr Tim Fox, CEng CEnv FIMechE FRSA, is the Institution's Head of Energy and Environment. His primary focus is providing thought leadership on how to sustainably meet the major challenges facing human populations in 21st Century, namely food, water, energy and shelter provision in the context of increasing environmental risk and depleting natural resources.

Contact Tim via Twitter @TimFox_IMechE.