Analysis of Critical Experiments Using Medium-Enriched-Uranium Fuel in Kyoto University Critical Assembly (KUCA)

Abstract

The critical experiments using medium-enriched-uranium (MEU) fuel in the Kyoto University Critical Assembly (KUCA), a light-water-moderated and heavy-water-reflected cylindrical core, were started in May 1981, as a part of the international Reduced Enrichment for Research and Test Reactors (RERTR) program. The following KUCA critical experiments were analyzed: (1) the criticality measurements for high-enriched-uranium (HEU) and MEU cores and (2) the reactivity effect measurements of boron burnable-poison (BP) for MEU cores. Five-group constants were generated using the EPRI-CELL code, and two-dimensional diffusion calculations were performed using a conventional finite-difference code DIF3D(2D), and a finite-element code 2D-FEM-KUR. Some of the results from the two diffusion codes were compared with each other. Advantage was taken of the finite-element method for the application of the 2D-FEM-KUR code to a detailed analysis of the BP effect measurements. Differences between the results of calculations and...