BOILING WATER TYPE NUCLEAR POWER PLANT

PURPOSE:To plan the reduction of dose rate by providing a heater recovering line for returning the drain of a low pressure feed water heater to the upstream side and the downstream side of a condensate demineralizer and controlling feed water iron concentration arbitrarily. CONSTITUTION:The steam which is used for heating feed water from a low pressure turbine 4 is guided in a low pressure heater drain tank 13, and connected to the upstream side line 17 and the downstream side line 19 of a condensate demineralizer 8 from a low pressure heater drain pump 14 through a low pressure heater drain line 1. Further, flow regulating valves 18, 20 are provided at the lines 17, 19 respectively and opening is regulated from the measuring result of feed water system iron concentration of a sampling line 21. At the beginning of plant operation starting much iron cladding is supplied in proportion to the concentration of eluted nickel and cobalt, and iron supply is reduced after a few years. Therefore, dose rate can be reduced.