| 摘要 |
PURPOSE:To keep off a leakage of primary steam in time of LOCA, by contituting such a valve that leaks no main steam from a main steam separator valve in time of the loss of a single power source in two of them fed to a control solenoid valve, while installing a control circuit in combination. CONSTITUTION:A valve 17 is set up at the downstream side of a solenoid valve 16, while an interlock to be closed by a closure completion signal out of a main steam separator valve is assembled therein. In the case where the main steam separator valve is closed, if an A power source is lost, main steam leaked from a fully opened solenoid valve 16 in a state of nonexcitation is intercepted by the valve 17 to be set in closing motion through a signal generated after main steam separation and full closure. Likewise, when the main steam separator valve is closed from its open state, steam inside a lower cylinder chamber 11 is discharged to a drain by way of the solenoid valve 16 and the valve 17 so that any motion in a piston 2 may not be hindered at all. |
