Fission Product Yields Covariance Generation Methodologies and Uncertainty Propagation Using the URANIE Platform

Abstract : In modern nuclear technology, integral reactor parameter uncertainty evaluation plays a crucial role for both economical and safety purposes. Recent safety-by-design standards require strict margins of uncertainty, then intense activities of verification and validation are therefore necessary to ensure the precision needed for safe and sustainable modern technologies exploitation. The uncertainty associated to nuclear data plays a relevant role in this sense and many efforts have been recently spent to improve the whole input chain we provide to reactor code design procedures. Since some of them are not sufficiently detailed or even do not exist in modern nuclear data libraries yet, in this work we propose a methodology to generate, test and propagate covariance matrices for fission product yields. The main goal is to reproduce the JEFF-3.1.1 fission yields library and find associated covariances to be propagated using Monte Carlo and deterministic techniques in burnup test-case calculations. Some results on the reactivity and decay heat uncertainty are presented for simple cases. Finally, a whole reactor geometries such as the Jules Horowitz Reactor (JHR), amaterial testing reactor under construction at CEA-Cadarache, is treated.