Viability of thorium-based nuclear fuel cycle for the next generation nuclear reactor: Issues and prospects

This paper presented a review on the past, present and the future of thorium fuel cycle. The aim of this study is to evaluate the developments in thorium fuel cycle, looking at the prospects and drawbacks on the possibility of thorium-based nuclear fuel for commercial reactors realising the increasing challenges of uranium-based nuclear fuel. The initial interest on thorium-based nuclear fuel and why it was abandoned at the early stage of nuclear technology were considered. Also, the reasons behind the present renewed interest on the viability of thorium fuel cycle as a valuable alternative to the conventional uranium-based fuel were studied. Thorium abundance, its physical, chemical and neutronic properties were evaluated in comparison to the uranium fuel cycle to determine thorium fuel sustainability for next generation nuclear industry. In this study, it was found that thorium fuel is three to four times more abundant, has higher conductivity, high melting temperature, low expansivity and more proliferation resistant compared to uranium fuel. The possible application and related challenges of thorium fuels in different reactor types and designs such as light water reactors (LWRs), high temperature gas-cooled reactors (HTGRs), heavy water reactors (HWRs), molten salt reactors (MSRs) and accelerator driven system reactors (ADSRs) were reviewed. The findings indicate that thorium fuel cycle can be used in the currently dominant LWRs designs in the nuclear industry with little technical modification, and also in other reactor types under investigation for future application especially molten salt breeder reactors, fast reactors and accelerator driven system reactors. Finally, this review made some recommendations on the short-term and long-term applications of thorium-based nuclear fuel cycle, and the issues that must be addressed before using thorium fuel for commercial reactor operations.