Criticality Analysis of Highly Enriched Uranium/Thorium Fueled ThermalSpectrum Cores of Kyoto University Critical Assembly

摘要

A series of critical experiments on thermal spectrum cores containingrnhighly enriched uranium and thorium have been performed at KyotornUniversity Critical Assembly (KUCA) of Research Reactor Institute, KyotornUniversity, Japan. Analysis of criticality (k-effective) have been performedrnusing continuous energy Monte Carlo code MVP and various nuclear datarnlibraries such as JENDL-3.2, JENDL-3.3, ENDF/B-VI.8 and JEFF3.0.rnIt has been found that the large overestimation of k-effective observed forrnJENDL-3.2 is significantly reduced by the use of JENDL-3.3. However,rnC/E values by JENDL-3.3 range from 1.007 to 1.009 and are significantlyrnlarger than C/E values of cores without thorium. Considerable spread amongrnthe 232Th cross sections exist and have been shown to have considerablernimpact on nuclear characteristics of thorium fueled thermal systems.rnAmong the nuclear data libraries considered in this study, ENDF/B-VI.8rnshowed the best results in terms of criticality prediction.