Alteration of reactor installation (alteration of heavy water criticality experiment facility) in Oarai Engineering Center, Power Reactor and Nuclear Fuel Development Corp. (Report)

The Nuclear Safety Commission presented the report to the Prime Minister on this alteration, on which the inquiry was made on August 25, 1987, after the prudent investigation and deliberation. It was recognized as the result of examination that the technical capability of the applicant is appropriate. It was judged as the result of examination that the safety after this alteration of reactor installation can be ensured. The mechanical design and the nuclear characteristics of the fuel assembly of 36 fuel rods having axial enrichment distribution and containing gadolinia, which comprises the uranium dioxide fuel rods containing gadolinia and the plutonium-uranium mixed oxide fuel rods having axial enrichment distribution or the already permitted plutonium-uranium mixed oxide fuel rods, were investigated. Gadolinia is chemically stable, and does not give harmful effect to cladding tudes. The axial distribution of the degree of enrichment of uranium and plutonium does not affect the mechanical design of fuel elements. It was confirmed that there is no problem in the nuclear design of the core. (Kako, I.)