Towards a Feasibility Study on BWR Burn-Up Credit

This paper presents our recent progress towards a feasibility study on BWR burn-up credit, the validation of the entire calculation chain and of all the involved codes. A sampling based uncertainty analysis was performed on a combined depletion and criticality calculation in order to obtain an integral overview of all effects involved and their impact on the reactivity of the spent fuel. The analysis is done by first calculating nuclide inventories for a number of 2D slices of a generic fuel assembly representing different axial positions of parametrized burn-up profiles. In a second step, these nuclide inventories are inserted into a corresponding 3D model for criticality analysis of a generic transport cask and fuel storage pool. An empirical model is provided which reflects the physical and technical correlations and constraints in the uncertain parameters. For this task the SUnCISTT [1] code was used, coupling depletion calculations with the HELIOS [2] code to criticality calculations with KENO-V.a from the SCALE package [3].In a preliminary step, uncertainty analyses were performed for the comparison between depletion calculations of BWR spent fuel isotopic composition experiments and their experimental values