| 摘要 |
PURPOSE:To prevent air leakage into a turbine gland section by gradually throttling the amount of vapor generated by an evaporator when the source of vapor of a turbine gland is switched from vapor generated by the evaporator to that by an auxiliary boiler. CONSTITUTION:When a nuclear reactor scram or other incident occurs, a main steam separation valve is all shut, and then a heating steam source is lost, a pressure control valve 11 is activated to open by a signal of a pressure controller 10 with the pressure drop of a gland steam seal header 12. In this case, the pressure control valve 11 is selectively given a signal transmitted from a lamp function converter in response to the all-shut signal of a main steam separation valve 2, with the help of a preference signal selector. With this constitution, the opening of the pressure control valve 11 is gradually done, vapor generated by residual heat of the evaporator 4 is slowly consumed, and residual heat operation time of said evaporator 4 is elongated. And the limit of allowable evaporation amount fluctuation rate of an auxiliary boiler is observed to achieve the desired object. |
