Reactor Core Isolation Cooling (RCIC) System

The RCIC is used in BWR-3 through BWR-6 boiling water reactor designs. The RCIC system is a single train standby system for safe shut down of the plant. The system is not considered part of the emergency core cooling system (ECCS), and does not have a loss of coolant accident (LOCA) function. The RCIC system is designed to ensure that sufficient reactor water inventory is maintained in the vessel to permit adequate core cooling. This prevents the reactor fuel from overheating in the event that the reactor is isolated from the secondary plant.

Following a normal reactor shut down, core fission product decay heat causes steam generation to continue, albeit at a reduced rate. During this time, the turbine bypass system diverts the steam to the maincondenser if the reactor is not isolated from the secondary plant, or to the suppression pool through operation of safety/relief valves (SRVs) if the reactor is isolated. The RCIC system supplies the makeup water required to maintain reactor vessel inventory. The turbine-driven pump supplies makeup water from the condensate storage tank (CST) to the reactor vessel. An alternate source of water is available from the suppression pool. The turbine is driven by a portion of the steam generated by the decay heat and exhausts to the suppression pool. This operation continues until the vessel pressure and temperature is reduced to the point that the residual heat removal (RHR) system can be placed into operation.

The initial system study is documented in "Reactor Core Isolation Cooling System Performance, 1987-1993" (NUREG/CR-5500, Volume 7 ). The links below provide the current information for the study and latest results.

Current Results (SPAR-based):

Historical Results (SPAR-based):

Historical Results (LER-based):

Supporting Information:

Page Last Reviewed/Updated Wednesday, August 31, 2022