Application of JENDL-5 to analysis of light-water-moderation core experiments implemented in the TCA and EOLE critical facilities

To expand the information on the performance in applying the JENDL-5 nuclear data library to the light-water moderation lattice cores, continuous-energy Monte Carlo calculation analysis was performed on the critical experiments implemented in the TCA and the EOLE critical facilities. For the homogeneous UO₂ cores of TCA, the differences in the calculated effective neutron multiplication factors (<i>k</i>_<i>eff</i>s) between JENDL-5 and JENDL-4.0 increased with the geometrical buckling of the cores. For the homogeneous mixed oxide (MOX) cores of TCA, the differences in <i>k</i>_<i>eff</i>s increased with the moderator-to-fuel volume ratios in the fuel cells. These trends were mainly attributed to the updated thermal neutron scattering law (TSL) of ¹H in water in JENDL-5. The trend in the <i>k</i>_<i>eff</i>s with the inventories of ²⁴¹Am in the full-MOX BWR mockup cores was improved in the calculated results with JENDL-5 due to the updated neutron capture cross-section of ²⁴¹Am. The scattering cross-section of water in JENDL-5 generally brought inferior performance in reproducing the measured core radial fission rate distributions in the cores with the heterogeneity in moderator such as BWR-type fuel assemblies, while the performance for the cores without the heterogeneity in moderator was almost the same as that with JENDL-4.0.