Uncertainty propagation of fission product yields to nuclide composition and decay heat for a PWR UO2 fuel assembly

Abstract

The assessment of the fission yield uncertainties on neutronic parameters is of great interest for criticality and spent fuel behavior studies. In this work, several fission yield perturbation methodologies are used to propagate the uncertainties for a PWR fuel assembly. Aside from the TENDL-2011 fission yields, a Generalized Least Square method is used on the JEFF-3.1.1 and the ENDF/B-VII.1 fission yields to generate correlations in agreement with the conservation equations. The branching ratios are also perturbed using this technique. Moreover the GEF code is employed to generate correlated fission yields from perturbed model parameters but also, coupled to a Bayesian process, to generate correlated fission yields for ENDF/B-VII.1. The resulting kinf uncertainty versus the exposure are assessed and discussed as well as nuclide density uncertainties at 60 GWd/tIHM and the decay heat uncertainty up to 105 days (274 years).