Experience to reduce the radiation exposure in Tsuruga 1, Tsuruga 2 and Tokai 2

At Tsuruga 1, Tsuruga 2 and Tokai 2, a radioactive corrosion product accumulates in a nuclear reactor cooling system during operation. And this radioactive corrosion product becomes the source of occupational radiation exposure at refueling outage. After the corrosion product which generated from structure material during operation is deposited on the fuel and activated, the radioactive corrosion product transports out of core and accumulates to the equipment and piping in the system. Therefore, control of generation, activation, transportation and accumulation and also removal of corrosion product from a nuclear reactor cooling system become important to reduce the radiation exposure during refueling outage. In this report, we describe the measures that we carried out for the radiation exposure dose of radioactivity reduction of a BWR plant and a PWR plant. (author)