Sensitivity and uncertainty analysis on keff due to nuclear data in the KRITZ-2:19 – Comparison between JENDL-4.0 and ENDF/B-VII.1

Abstract

In criticality and stability studies of the nuclear reactor, it is important to evaluate the impact of the uncertainties of the basic nuclear data (cross sections) on the different neutron parameters. In this work sensitivity and uncertainly analysis of KRITZ-2:19 experiment at 21.1 °C was carried out with respect to cross-section uncertainties of 1H, 10B, 16O, 235U, 238U, 239Pu, 240Pu, 241Pu and 241Am isotopes on the effective multiplication factor ” keff ” for JENDL-4.0 and ENDF/B-VII.1 evaluated libraries. Sensitivity vectors calculated by card KSEN/MCNP6.1 have been combined with the covariance matrices (from ENDF/B-VII.1, JENDL-4.0, and/or ENDL-3.2) generated by the ERRORJ module of NJOY2016 to produce nuclear data uncertainties. Comparison between JENDL-4.0 and ENDF/B-VII.1 evaluated libraries consistency among the calculated-to-experiment values of keff and the overall computational uncertainties is discussed. The keff was found to have the largest sensitivity to fission and capture cross-sections of 239Pu for the two libraries JENDL-4.0 and ENDF/B-VII.1. Neutron fission reaction of 239Pu for the two evaluated libraries was found to contribute to the major part of the keff uncertainty due to the cross-sections. The discrepancy of the calculated and measured keff values was strongly correlated with the uncertainty in the calculated keff due to the 239Pu neutron fission cross-section uncertainty.