2003 年 2 巻 4 号 p. 532-545
Maintenance methods and procedures for the power conversion system of the Gas Turbine High Temperature Reactor 300 (GTHTR300) were examined. Because of being installed in the power conversion vessel which is primary pressure boundary and exposed to primary coolant contaminated with fission products, unique methods and procedures which are different from those for existing power plants and High Temperature Engineering Test Reactor (HTTR) are needed for especially the gas turbine and the compressor. The gas turbine-compressor assembly is pulled out from the power conversion vessel by a special trolley after generator vessel section is separated. Then, the gas turbine-compressor assembly is lifted and carried to a maintenance facility by a building overhead crane. During the removal process, preventive measures to reduce the exposure are taken by limiting working time and bagging the assembly to keep fission products from scattering. Before casings are open, the gas turbine-compressor assembly shall be in storage for a certain period to reduce the dose rate. In order to achieve a high plant availability, a spare gas turbine-compressor assembly is installed as an alternative to the assembly cooled in the storage. It was confirmed that, by applying those proposed methods and procedures, it is possible to keep the plant availability more than 90%. Present study is entrusted from the Ministry of Education, Culture, Sports, Science and Technology of Japan.