BWR type reactor

Purpose: To rapidly and surely return the fluctuations of the pressure within a pressure vessel to a normal value. Constitution: A cooling water spray device is disposed at an upper portion (where steams are present) of a pressure vessel. Cooling water is always sprayed from the spray device to the steam area within the pressure vessel to maintain the pressure always at a certain level. The amount of spray water is increased in the case of pressure increase and decreased in the case of pressure lowering to thereby maintain the pressure at a certain level even if external disturbances should occur. (Ikeda, J.)