Use of integral data assimilation and differential measurements as a contribution to improve 235U and 238U cross sections evaluations in the fast and epithermal energy range

This work makes use of the Generalized Least Square method to solve Bayes equation, as implemented in the CONRAD code. Experimental database used includes ICSBEP Uranium based critical experiments and benefits from recent re-analyses of MASURCA and FCA-IX criticality experiments (with Monte-Carlo calculations) and of PROFIL irradiation experiments. | Use of integral data assimilation and differential measurements as a contribution to improve 235U and 238U cross sections evaluations in the fast and epithermal energy range EPJ Nuclear Sci. Technol. 4 41 2018 Nuclear Sciences V. Huy et al. published by EDP Sciences 2018 amp Technologies https epjn 2018035 Available online at https REGULAR ARTICLE Use of integral data assimilation and differential measurements as a contribution to improve 235U and 238U cross sections evaluations in the fast and epithermal energy range Virginie Huy1 2 Gilles Noguère1 and Gérald Rimpault1 1 CEA DEN DER SPRC Cadarache 13108 St Paul-Lez-Durance France 2 ED352 Doctoral School AMU Luminy Campus 13288 Marseille France Received 7 December 2017 Received in final form 1 March 2018 Accepted 22 May 2018 Abstract. Critical mass calculations of various HEU-fueled fast reactors result in large discrepancies in C E values depending on the nuclear data library used and the configuration modeled. Thus it seems relevant to use integral experiments to try to reassess cross sections that might be responsible for such a dispersion in critical mass results. This work makes use of the Generalized Least Square method to solve Bayes equation as implemented in the CONRAD code. Experimental database used includes ICSBEP Uranium based critical experiments and benefits from recent re-analyses of MASURCA and FCA-IX criticality experiments with Monte-Carlo calculations and of PROFIL irradiation experiments. These last ones provide very specific information on 235U and 238U capture cross sections. Due to high experimental uncertainties associated to fission spectra we chose to consider either fitting these data or set them to evaluations. The work focused on 235U and 238U evaluations and results presented in this paper for 235U capture and 238U capture and inelastic cross sections are compared to recent differential experiment or recent evaluations. Our integral .