Development of the decommissioning management system (6). Evaluation of decommissioning method for JWTF old structure

An estimation for decommissioning of JWTF old structure using decommissioning management system was done to confirm 'work term', 'work quantity', 'exposure dose', 'quantity of radioactive waste', and 'cost'. Two different decommissioning methods are used in the estimation work. The two methods are as follows. Method A: Cutting work is done in the spot of equipments, waste occurred in the cutting work are stored in a waste container, and the waste is keep in a waste storage place. Method B: In cutting work, equipments are dismantled to container size in the spot of decommissioning place, and also are dismantled in more small size in exclusive waste treatment facility, and are kept in the exclusive store place. The simulation named method B was ended before the waste was bought in the exclusive waste treatment facility, because we have not had the waste treatment facility. Those results are shown in the following. (1) Work term: 732days using the method A, and 517days using the method B. (2) Work quantity: 10,023 man · days using the method A, and 6,931 man · days using the method B. (3) Exposure dose: 61,967 man · mSv using the method A, and 37,606 man · mSv using the method B. (4) Quantity of radioactive waste: 69,112kg using the method A, and 68,929kg using the method B. (5) Cost: 696,553 thousand yen using the method A, and 442,533 thousand yen using the method B. (author)