Fundamental Properties for Evaluation of Uranium-free TRU-Zr Metal Fuel Performance

FR (Fast Reactor) is widely recognized to effectively burn plutonium and MA (Minor Actinides) (i.e., TRU: Transuranic) due to its higher fission-to-neutron-capture ratio compared to LWR. When TRU in LWR (Light Water Reactor) spent fuel is recycled into FR cycle, the radiotoxicity of the residual nuclear wastes from LWR spent fuel is reduced to natural uranium level after several hundred years instead of more than hundreds of thousand years for no recycling case. It could significantly improve public perception to nuclear waste disposal and might reduce the burden of the disposal. However, U-TRU-fueled fast reactors also produce TRU while burning TRU because they use uranium together with TRU. For example, FR, even with low conversion ratio of 0.75, burns only 0.18 t TRU/GWe/y, while LWRs produces about 0.22 t TRU/GWe/y. It is not a realistic scenario which needs almost the same capacity of fast reactors as that of LWRs to continuously burn TRU at LWR-dominant era in the near term at least. Therefore, a FR system to burn TRU from LWR with the minimum reactor units is desirable. The most effective way is to use uranium-free TRU fuel since it does not produce any new TRU. It can reduce the capacity of the TRU burner units and the associated fuel cycle facilities to about 1/5 and 1/8 respectively. Metal fuel FR cycle is considered to be one of the most promising ways because uranium-free TRU metal fuel could be recycled by pyro-process for U-Pu-Zr metal fuel without large modifications. This paper shows the recent research progress on fundamental properties of uranium-free TRU metal fuel. (authors)