Experiment on Local Power Peaking in BWR Type Fuel Assembly

Abstract

Local power peaking was measured by γ-scanning in BWR type fuel assemblies under cold clean conditions using the zero-power critical facility TCA. The horizontal power distribution in an assembly was examined on several loading patterns made up of 1.9, 2.1, 2.3 and 2.6% ²³⁵U enriched UO₂ fuel rods. The power depression was correlated with the lowered value of ²³⁵U enrichment in a fuel rod loaded in the assembly to replace one of normal enrichment. The results show that the local power peaking factor can easily be depressed down to 1.3 by suitable arrangement of depleted fuel rods in the assembly, while more elaborate manipulation is required to reduce it below 1.2.