| 摘要 |
PURPOSE:To control stress corrosion cracks by providing a steam supply apparatus for stress corrosion crack prevention which is composed of a vaporizer and a heater so that the dry steam generated therein may be supplied to those areas such as key grooves which are subjected to the stress corrosion crack. CONSTITUTION:The steam generated in a nuclear reactor 20 is supplied to high and low pressure steam turbines 24, 26 to do its work, and is thereafter condensed in a condenser (not shown in a diagram) to be returned to the reactor 20. In such a plant, a gland seal steam supply apparatus 30 having a vaporizer 31 which vaporizes the condensed water in a condensed water reservoir tank 27, and a steam supply apparatus 40 for stress corrosion crack prevention which shares the common vaporizer 31 are provided. This steam supply apparatus 40 is so constructed that the dry steam which is generated in the vaporizer 31 and heatd in a heater 42 by steam in a steam pipe 21b may be supplied to a through- hole 53 of a nozzle diaphragm 52 through a reducing valve 43. And, the dry steam is supplied to key grooves 4, 5 through a clearance 54 which is formed between bases of a disc 2 of respective turbine rotors. |
