NUCLEAR POWER PLANT, FUEL ASSEMBLY AND METHOD FOR REDUCING RADIATION EXPOSURE IN NUCLEAR POWER PLANT

摘要

PPROBLEM TO BE SOLVED: To provide a method for reducing radiation exposure in a nuclear power plant which can further reduce radiation exposure even if the burnup of fuel assemblies is increased further. PSOLUTION: A BWR plant 1 includes a core 4 loaded with fuel assemblies 5 and feedwater pipes 9 which are connected with a condenser 8 and a reactor pressure vessel (RPV)3 and where a hollow filter 10 is placed. The placement of the hollow filter 10 restrains the concentration of iron oxide in the feedwater supplied into the RPV 3 to 110SP-9/SPmol/kg or less. A ferrite coating is formed on the outside face of a cladding tube used for each fuel rod included in the fuel assemblies 5. Even if cobalt oxide in reactor water adheres to the ferrite coating, it is exfoliated from the outside face of the cladding tube through the agency of the electrostatic repulsive force generated between the cobalt oxide and triiron tetraoxide. This restrains nonradioactive cobalt from being activated on the outside face of the cladding tube and reduces the concentration of radioactive cobalt in the reactor water. PCOPYRIGHT: (C)2010,JPO&INPIT