Uncertainty analysis of Lead cross sections on reactor safety for ELECTRA

¹ Division of Applied Nuclear Physics, Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
² Nuclear Research and Consultancy Group (NRG), Petten, The Netherlands

Abstract

The Total Monte Carlo (TMC) method was used in this study to assess the impact of Pb-206, 207 and 208 nuclear data uncertainties on k_eff , β_eff, coolant temperature coefficient, the coolant void worth for the ELECTRA reactor. Relatively large uncertainties were observed in the k_eff and the coolant void worth for all the isotopes with significant contribution coming from Pb-208 nuclear data. The large Pb-208 nuclear data uncertainty observed was further investigated by studying the impact of partial channels on the k_eff and the β_eff. Various sections of ENDF file: elastic scattering (n, el), inelastic scattering (n, inl), neutron capture (n, γ), (n, 2n), resonance parameters and the angular distribution were varied randomly and distributions in k_eff and the β_eff obtained. The dominant contributions to the uncertainty in the k_eff from Pb-208 came from uncertainties in the resonance parameters; however, elastic scattering cross section and the angular distribution also had significant impact. The impact of nuclear data uncertainties on the β_eff was observed to be small.