MAIN STEAM RELIEF SAFETY VALVE

摘要

PROBLEM TO BE SOLVED: To provide a main stream relief safety valve for ensuring being opened by a specified blow-out pressure and being closed by a specified blow-up pressure. SOLUTION: This main steam relief safety valve which consisting of an actuator 1 having a spring 4 mounted on a valve stem 3 in a case 6 and a piston 5 and a valve body 2 formed at the end of the valve stem is installed on a main steam pipe for supplying steam from a reactor to a steam turbine system for guiding driving fluid into the actuator and thrusting the piston, whereby the spring is deenergized to cause the opening of the valve body with steam pressure in the main stream pipe. An exhausting device 20 is provided for exhausting the driving fluid which stays in the actuator and operates in the direction of closing the valve body.