Pressure regulator for a reactor container

Purpose: To moderate impact shocks applied to structural materials upon loss of coolant accidents. Construction: A reactor pressure vessel is disposed within a dry well of a reactor container bisected at a disphragm floor, and the dry well and a pressure suppression chamber are communicated to each other by a plurality of vent pipes having different diameters. Upon loss of coolant accidents in the reactor, coolants or steams at high temperature and at high pressure are diffused from the reactor pressure vessel and pipeways into the dry well, thereby rapidly condensate nitrogen gases or airs sealed in the dry well and discharge them by way of a plurality of vent pipes into pool water in the pressure suppression chamber. Since the shock waves are thus generated asynchronously at the exits of respective vent pipes due to steam condensation and interference is resulted therebetween, the load exerted on the wall of the pressure suppressure chamber can be reduced to thereby improve the reliability of the suppression chamber. (Moriyama, K.)