Control device for reactor residual heat removal system

Purpose: To enable safe and quick cooling of a reactor. Constitution: When the water level deviation (or the detected water level) of a reactor exceeds reference values, water level control means are switched to interrupt the cooling speed control, to preferentially control the water level and to control the water filling flow rate to the reactor in response to the variation in the water level. When the water level deviation (or the detected water level) is within the reference values and the cooling speed deviation (or the detected cooling speed) exceeds reference values, the water level control is temporarily interrupted so as to preferentially control the cooling speed having quick response. Since the cooling speed control and the water level control have priority according to the state of the reactor, the reactor can be cooled safely in a short time. (Yoshihara, H.)