ASSESSMENT OF TRANSURANICS STABILIZATION IN PWRs

The stabilization of transuranics (TRU) in a PWR fuel cycle was evaluated for the CORAIL assembly. Alternative assembly designs (a highly moderated and modified CORAIL-TRU assembly and a homogeneous Thorium-TRU assembly) were also investigated to assess the potential of obtaining a near-zero TRU mass balance (i.e., the net TRU production per assembly) and low power peaking factor. The radiotoxicity of the nuclear waste sent to the repository environment and the impact of TRU stabilization on the future TRU stockpile were also evaluated. Assembly level mass flow analyses have shown that TRU mass balances in the range of 0.2 to 1.4 kg/assembly are achievable within 7 recycles of the TRU, compared with 6.5 kg/assembly for a reference UO2 assembly. The study also revealed that the radiotoxicity of the repository waste generated by these TRU-containing assemblies at 10 years after disposal is roughly half that of a reference UO2 assembly; furthermore, the radiotoxicity falls below that of natural uranium ore after about 500 years because only a small fraction of the TRU (0.1%) is passed to the waste repository. Finally, the future TRU stockpile could be reduced by implementation of TRU multi-recycling in the CORAIL or alternative assemblies in a current-generation PWR core.