[2I16-19] Uncertainty Evaluation

[2I17] Uncertainty Quantification of Reactivity in KUCA-C cores with HEU Fuel

*Kota Morioka¹, Cheolho Pyeon¹ (1. Kyoto Univ.)

Keywords:Kyoto University Critical Assembly (KUCA), Highly-enriched uranium (HEU) fuel, Eigenvalue bias, Uncertainty, Reactivity

In the previous study, eigenvalue bias in criticality in the KUCA-C cores with HEU fuel ranged between 400 and 700 pcm. Uncertainty analyses of reactivity are performed for clarification of reason for eigenvalue bias with the use of SCALE6.2.4 code system. Here, uncertainty for reactivity induced by nuclear data is 10% at most by TSAR, and then contribution rate of χ value of U-235 fission reactions is more than 70% after the cross-section adjustment by TSURFER. From the results, it is confirmed that the eigenvalue bias is caused mainly by the uncertainty of χ value of U-235.