TY - JOUR

T1 - A review of alternative finishing options for uranium/plutonium and minor actinide nitrate products from thermal and fast reactor fuels reprocessing

AU - Colledge, H.

AU - Sarsfield, M.

AU - Taylor, R.

AU - Boxall, C.

PY - 2023/11/30

Y1 - 2023/11/30

N2 - In fuel reprocessing, product finishing is the conversion of aqueous metal nitrates into solid forms that can either be re-used in new fuels or safely interim stored and so is the key step at the interface between reprocessing and fuel manufacturing processes. Conversion processes were originally developed for the fabrication of oxide fuels and have typically involved the generation of UO 3 (or U 3O 8) and PuO 2 powders as separate products. However, whilst this is an industrial proven process, research and development of mixed oxide (MOX) fuels and minor actinide targets by advanced reprocessing routes is also underway. It is envisaged that advanced recycle processes will allow the multi-recycling of plutonium and the transmutation of minor actinides into shorter lived isotopes to enhance sustainability of the nuclear fuel cycle and fully utilise fissionable material recoverable from spent fuels whilst improving a number of key features over current conversion processes including: product conversion efficiency, higher throughput, flexibility in product specification, proliferation resistance and a reduction in the number of waste streams produced. Internationally, research programmes to examine future options for advanced fuel cycles are focusing on the development of advanced reprocessing flowsheets for future actinide recycling. It is anticipated that these separation processes will produce a range of mixed transuranic (TRU) actinide nitrate products rather than the separated pure plutonium stream produced in current reprocessing plants. The easiest assumption is that these nitrate products will be converted to oxides by the oxalate co-precipitation route. However, this has certain limitations. The focus of this review is to identify any alternative nitrate to oxide conversion processes which have been applied to mixed oxides and evaluate their suitability for MOX production. A variety of factors including process complexity, technical maturity, effluent treatment/recycling and scale up into an industrial process will also be considered.

AB - In fuel reprocessing, product finishing is the conversion of aqueous metal nitrates into solid forms that can either be re-used in new fuels or safely interim stored and so is the key step at the interface between reprocessing and fuel manufacturing processes. Conversion processes were originally developed for the fabrication of oxide fuels and have typically involved the generation of UO 3 (or U 3O 8) and PuO 2 powders as separate products. However, whilst this is an industrial proven process, research and development of mixed oxide (MOX) fuels and minor actinide targets by advanced reprocessing routes is also underway. It is envisaged that advanced recycle processes will allow the multi-recycling of plutonium and the transmutation of minor actinides into shorter lived isotopes to enhance sustainability of the nuclear fuel cycle and fully utilise fissionable material recoverable from spent fuels whilst improving a number of key features over current conversion processes including: product conversion efficiency, higher throughput, flexibility in product specification, proliferation resistance and a reduction in the number of waste streams produced. Internationally, research programmes to examine future options for advanced fuel cycles are focusing on the development of advanced reprocessing flowsheets for future actinide recycling. It is anticipated that these separation processes will produce a range of mixed transuranic (TRU) actinide nitrate products rather than the separated pure plutonium stream produced in current reprocessing plants. The easiest assumption is that these nitrate products will be converted to oxides by the oxalate co-precipitation route. However, this has certain limitations. The focus of this review is to identify any alternative nitrate to oxide conversion processes which have been applied to mixed oxides and evaluate their suitability for MOX production. A variety of factors including process complexity, technical maturity, effluent treatment/recycling and scale up into an industrial process will also be considered.

KW - Finishing

KW - Mox

KW - Denitration

KW - Oxalate Co-Precipitation

KW - Gelation

KW - Co-conversion

U2 - 10.1016/j.pnucene.2023.104903

DO - 10.1016/j.pnucene.2023.104903

M3 - Journal article

VL - 165

JO - Progress in Nuclear Energy

JF - Progress in Nuclear Energy

SN - 0149-1970

M1 - 104903

ER -