| 摘要 |
PURPOSE:To suppress quickly the generation of the corrosion product from the heater tubes of a feed water heater of a nuclear reactor by supplying high-temp. water inject ed with oxygen to the wetting surfaces of the heater tubes so that a preliminary oxidation treatment is executed prior to the starting of the nuclear reactor. CONSTITUTION:A closed loop is formed by providing a branch line between the feed water line and feed water circulation line 13 of a pressure vessel 12 of the nuclear reactor consisting of a turbine 1, a condenser 2, a low-pressure feed water heater 6, a high-pressure feed water heater 8, etc. The branch line is connected to the outlet of the heater 6 and the line 13 and is constituted of a heater 14, a high-temp. dissolved oxygen meter 15 and a dissolved oxygen preparation tank 16. The pure water is introduced to the closed loop and thereafter the water is kept circulated by a pressure increasing pump 7, then the reactor is operated for the prescribed period while the temp. of the water and the concn. of the dissolved oxygen in the closed loop are controlled under prescribed conditions by using the dissolved oxygen preparation devices 15, 16, 17. (The lower limit temp. is aobut 230 deg.C and the concn. of the dissolved oxygen about 500ppb when, for example, the hydrothermal treatment time is 20 hours.)
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