• Energy Research
• OA Publications Mandate: No close
• 2011 close

Nuclear fission is currently internationally recognised as a key low carbon energy source, vital in the fight against global warming, which has stimulated much interest and recent investment. For example, RCUK's energy programme has identified nuclear fission as an essential part of the "trinity" of future fuel options for the UK, alongside renewables and clean coal. However, nuclear energy is controversial, with heartfelt opinion both for and against, and there is a real requirement to make it cleaner and greener. Large international programmes of work are needed to deliver safe, reliable, economic and sustainable nuclear energy on the scale required in both the short and long term, through Gen III+ & Gen IV reactor systems. A pressing worldwide need is the development of specific spent fuel reprocessing technology suitable for these new reactors (as well as for dealing with legacy waste fuel from old reactors). The REFINE programme will assemble a multidisciplinary team across five partner universities and NNL, the UK's national nuclear laboratory to address this fuel reprocessing issue. The consortium will carry out a materials research programme to deliver fuel reprocessing by developing materials electrosynthesis through direct oxide reduction and selective electrodissolution and electroplating from molten salt systems. Developing, optimising and controlling these processes will provide methods for, and a fundamental understanding of, how best to reprocess nuclear fuel. This is in addition to the development of techniques for new molten salt systems, new sensing and analysis technologies and the establishment of the kinetics and mechanisms by which molten salt processes occur. This will facilitate rapid process development and optimization, as well as the generation of applications in related areas. A key output of the programme will be the training and development of the multidisciplinary UK researchers required to make possible clean nuclear energy and generate complementary scientific and technological breakthroughs.

Uranium has been the fuel for the world's commercial nuclear power stations. Its reserves are, however, finite and the demands of planned Generation III 'New Build' reactors could consume much of the available supply. Options are available to increase nuclear fuel sustainability: developing novel extraction methods (e.g. uranium from sea water and phosphate mining); nuclear fuel can be reprocessed; fuel efficient fast reactors can be developed; or thorium, which is 3-4 times more abundant than uranium, can be adopted as an alternative fuel. This research considers key aspects of the thorium option.Historically a handful of commercial reactors have been fuelled in part by thorium. Due to economic drivers the cycle has not been adopted in contemporary commercial reactors. In the future this may change. Notably India, and in particular its Bhabha Atomic Research Centre, has pioneered the use of thorium and intends for it to form an integral part of its energy generation plans. Its Kakrapar-1 reactor has used fuels containing thorium and major new thorium fuel developments are underway.Fuel selection has an important effect on sustainability and proliferation resistance. India has given much attention to re-processing fuel cycles. We seek to assess an alternative, the open or 'once-through' cycle, against a range of criteria. The open cycle will be considered in two broad domains: sustainability and proliferation resistance. In both domains some metrics and assessment frameworks already exist. Discussions of nuclear energy sustainability are often dominated by considerations of fuel resource depletion; economic, social and environmental sustainability are not emphasised. We intend to take full consideration of the impacts of thorium use from mineral extraction, through processing and reactor use to the disposal of all associated waste materials. Proliferation metrics are less mature, but methodologies for quantifying risks of nuclear proliferation are being developed.The proposed research aims to assess, validate and improve metric frameworks for nuclear sustainability and proliferation resistance. It will culminate with the creation of a single unified assessment framework. This work is driven by examining the particular attributes of proposed open cycle thorium reactors. The research programme is formed via three key areas of work:1) A review of proliferation resistance and sustainability assessment methodologies, with emphasis on quantitative measurements; where necessary methods will be improved. An umbrella assessment framework will be developed encompassing proliferation resistance and sustainability allowing for a harmonised and directly comparable assessment of different reactor designs.2) A review of proposed open cycle thorium-fuelled nuclear reactor designs. The review will include identifying the front- and back-end fuel composition of the designs. It will emphasise sustainability and proliferation resistance characteristics by addressing their wider resource and emission consequences and identifying associated proliferation risks. Our work will advance proliferation assessment to go beyond the attributes of the fuel itself, to include consideration of the infrastructure context.3) The reviewed reactor designs will be assessed within the newly developed umbrella sustainability and proliferation resistance framework. The relative positive and negative features of each of the designs will be measured. These designs will also be compared to mature light water reactor technology.The research will directly provide an improved understanding of the costs and benefits of thorium as an energy source. The assessment framework will improve quantitative assessments of proliferation risks and nuclear sustainability. The framework will be disseminated to the wider global nuclear community allowing them better to select technologies for the benefit of local and international populations.