Criticality and sensitivity/uncertainty analysis of the DNRR with LEU fuel using MCNP6.3 and the latest data libraries

Criticality and sensitivity/uncertainty analysis was conducted for the Dalat Nuclear Research Reactor (DNRR) with 92 low enriched uranium (LEU) fuel bundles using the MCNP6.3 code and the latest nuclear data libraries such as ENDF/B-VIII.0, JENDL-5, JEFF-3.3 and CENDL-3.2. Criticality analysis was conducted for thirty critical conditions of the DNRR corresponding to different control rod positions established experimentally in comparison with the measurements and among the data libraries. A good agreement was found between the calculations and experiments with the discrepancy of the $k_{eff}$ less than 354 pcm. Whereas, the discrepancies among the data libraries are within 172 pcm. The uncertainties of the $k_{eff}$ caused by the data libraries of ENDF/B-VIII.0, JENDL-5, JEFF-3.3 are 415.7, 363.0 and 588.0 pcm, respectively. Based on the analysis, improvements in cross-section evaluations for H-1, U-235, Al-27, and Be-9, particularly regarding the capture and elastic scattering of H-1 and the fission of U-235, are recommended to enhance the reliability of core analysis for the DNRR. The evaluations have identified ENDF/B-VIII.0 and JENDL-5 libraries as the most reliable and should be prioritized for future core physics and safety analyses of the DNRR and similar reactor.