JPDR配管検査時の遮蔽設置についての費用・利益解析

抄録

During the test operations of JPDR-II (BWR), cracks were detected at primary pipe nozzle, and the inspections were made over about 2.5 years.
In this report, the procedures such as shielding and removal of fuels which were taken to reduce radiation exposure during the inspections are summarized and the cost-benefit analysis of the shieldings were attempted to determine whether the optimum shieldings were made or not.
The radiation doses was measured to be about 62 man·rem for 420 workers and the maximum individual dose was 1.3rem. The average cost to reduce exposures at various working areas was calculated approximately 1.4×10⁵yen/man-rem.
Especially, the provisional shielding at under core area reduced 61 man-rem and its reduction cost was 8.9×10⁶ yen. Assuming that the economic and social detriment cost is 1, 000$/man-rem, it seems that the optimum shielding were taken, although the optimum conditions shifted depending on the economic and social detriment cost which cannot be simply determined. It was found that the optimum conditions depended on the order of combination of the provisional shields.