Impact of nuclear data uncertainties on closed fuel cycle scenarios: Preliminary assessment

Nuclear energy is considered today, despite recent events, a reliable, clean and cost effective energy source. As environment protection and availability of natural resources are becoming crucial issues, nuclear research is focusing on innovative reactors and associated fuel cycles able to optimise resource exploitation and nuclear waste management. In order to minimise waste inventories, the proposed fuel cycles use partitioning and transmutation strategies. Implementation of these cycles may influence appreciably parameters such as fuel radiation activity during fabrication, waste decay heat and radiotoxicity in a final repository. Therefore, it is necessary to identify the most important isotopes, which are the major contributors to those parameters. It is also important to assess the associated uncertainties, due essentially to uncertainties in neutron cross-sections. For this purpose, different scenarios have been analysed with the COSI code and NUCLEONICA, the latter being used for decay calculations. The first outcome of these analyses, i.e. the assessment of the most important nuclei for the evaluation of doses in fuel fabrication, of decay heat in fuel discharge and in a repository, of waste radiotoxicity, etc. is presented in the paper. (authors)