Target accuracy of MA nuclear data and progress in validation by post irradiation experiments with the fast reactor 'JOYO'

This paper presents a discussion about the target accuracy of MA nuclear data for fast reactor cycle system development, as well as the validation work on those nuclear data by PIE analyses. The PIE analyses are in progress on fuels and MA samples (237Np, 241Am, 243Am, 244Cm) irradiated at the experimental fast reactor 'JOYO'. The analysis result on the first examined MA sample suggested the necessity of re-evaluation of the isomeric ratio for 241Am capture reaction both in ENDF/B-VI and in JENDL-3.3. The above result contributes to the uncertainty-reduction both of burnup reactivity loss and of gamma energy release from fuel assemblies. (author)