manufacture of mox fuel for nuclear reactor with thermal neutrons

摘要

PURPOSE:To decrease the kinds and amts. of fuel rods contg. plutonium by averting the provision of uranium fuel parts and uranium blanket parts on the fuel rod contg. the plutonium. CONSTITUTION:The other fuel rods excluding the fuel rods in the corner positions on the outermost periphery of a grid-shaped fuel rod disposition are partly substd. with the fuel rods contg. the plutonium. In addition, the fuel rods contg. the plutonium are not provided with the uranium fuel parts and uranium blanket parts. Namely, 18 pieces of the high-enrichment fuel rods in the central part of the uranium fuel assembly are substd. with the fuel rods consisting of the oxide mixture composed of the uranium and plutonium (MOX). Eighteen pieces of these MOX fuel rods are constituted by substituting the uranium fuel rods of the enrichment higher than the enrichment of the fuel rods existing in the peripheral part of the conventional enriched uranium fuel assembly with the MOX fuel rods. The degree of enrichment of the plutonium is, therefore, increased and the number of the fuel pellets and the number of the fuel rods in the case of working of a specified amt. of the recovered plutonium to the MOX fuel are decreased by adopting the MOX fuel rods to the fuel rods in these positions.