Predictive accuracy of neutronics of light-water-moderated and graphite-reflected core with low-enriched uranium fuel at UTR-KINKI

Numerical experiments are carried out using the MCNP6.2 code with the ENDF/B-VII.1 nuclear data library for the University Teaching and Research Reactor in Kindai University (UTR-KINKI) with low-enriched uranium (LEU) fuel, including the approach-to-criticality, control rod calibration, and neutron spectrum experiments. Sensitivity and uncertainty of criticality are also quantified by using eigenvalue and uncertainty analyses using the KENO-VI and TSUNAMI-3D modules of the SCALE6.2.4 code system, respectively. The criticality and reactivity in the LEU core by the MCNP6.2 eigenvalue calculations notably provided the same neutronics characteristics as those in the highly enriched uranium (HEU) core. In terms of TSUNAMI-3D, the uncertainty of criticality in the LEU core is determined mainly by those of cross-section data of uranium-235 X value, νˉ value, fission, and capture reactions. From a series of numerical experiments by MCNP6.2 with ENDF/B-VII.1, the LEU core has the same neutronics characteristics as those of the HEU core, with the conclusion that the LEU conversion could be successfully implemented at UTR-KINKI.