JENDL-5.0 nuclear data sensitivity, uncertainty, and similarity analyses on the criticality of RSG GAS multipurpose research reactor

The criticality, sensitivity, uncertainty and similarity analysis of the clean, first core of the G. A. Siwabessy Multipurpose Reactor (RSG GAS), using the newly released Japanese Nuclear Data Library version 5 (JENDL-5) was conducted to contribute the validation effort of the JENDL-5, especially for the application on beryllium reflected, light-water moderated, low-enriched uranium (19.75 wt%) fueled material testing reactors. The JENDL-5 sensitivity coefficients and covariance matrices were prepared by MCNP6 and AMPX-6, respectively. The keff uncertainty was then evaluated with TSUNAMI-IP module of SCALE-6. The same module was used for similarity analysis by comparing the sensitivity data of 3,690 criticality experiments. The criticality (keff) analysis results ([C/E-1]) showed maximum overestimation of 801 pcm, 477 pcm and 547 pcm, for JENDL-5, JENDL-4.0 and ENDF/B-VIII.0, respectively. The keff uncertainty originated from the nuclear data was estimated to be 620 pcm, 644 pcm and 637 pcm for JENDL-5 only, JENDL-5 & ENDF/B-VIII.0, and ENDF/B-VIII.0 covariance data, respectively, which are comparable with the keff ([C/E-1]) values. About 125 experiment cases were found to have correlation factors of > 0.8, however, no experiment showed a strong correlation factor (>0.9), therefore, in the future criticality experiments similar to the RSG GAS should be conducted.