(510d) Managing Spent Fuel Resources – Closing the Loop

Wide spread deployment of nuclear power plants is curtailed due to three critical issues associated with the nuclear fission technology – safety (plant accidents and nuclear waste), security (facilities and material) and safeguards (proliferation of nuclear weapons material). These three inherent technology specific challenges coupled with energy economics and policy continues to plague nuclear power to realize its full potential. The development in electrometallurgical processing techniques and Gen IV reactors are some of the key enabling technological advancements that could shape the the future for nuclear fuel management. The elements of nuclear – chemical fundamentals is inherent to this new developments.

The global spent nuclear fuel (SNF) inventory will reach 400,000 tonnes by 2025. The SNF inventory in US reaching 70,000 MTU peaking spent pool storage capacity at several sites within US. In early 1980s the nuclear power plants began to move spent fuel assemblies to on-site dry cask storage to address this crisis. Many nuclear power countries, France, UK, Russia and Japan among others, use reprocessing and recycling as a strategy for management of SNF. China is rapidly expanding it reprocessing capacity to close the Chinese nuclear fuel cycle and to manage SNF inventory. India due to its low uranium resources and an interest in thorium fuel cycle has built in reprocessing as part of its fuel resource management strategy. South Korea, currently does not reprocess, has invested significantly in the development of the pyroprocessing technology to manage the rapidly growing SNF inventories (~700 tons per year) in Korea. The United State pioneers in the development reprocessing technologies put a moratorium on reprocessing of commercial SNF in late 1970s with the overarching goal to halt the spread of fuel reprocessing technologies worldwide. Although, the global reprocessing capacity is about 4500 tons per year and continues to grow as more countries add nuclear power to their energy mix.

Besides nonproliferation concerns there are several other factors that contribute to the limited viability of reprocessing as a comprehensive SNF management option today. The reprocessing technology, PUREX, is hydrometallurgical process that separates uranium and plutonium. Recycling reprocessed uranium (RepU) directly into the LWR is challenging due to the presence of U-232 (radiotoxicity) and U-236 (high neutron absorption cross-section). Presence of these two isotopes in RepU require higher enrichment and increased fuel handling cost. Hence currently RepU is typically stored and not recycled. The plutonium from the PUREX has to be used rather quickly to reduce risks of proliferation and to limit the production of Am-241 (radiotoxicity). PUREX process does not produce a separated stream of minor actinides leading to a waste stream with mixed long- and short lived isotopes a distinct negative from waste management prospective.