Patent Number: 055704018
Section: abstract

An improved containment configuration for a boiling water reactor in which the wetwell airspace is divided into a multiplicity of chambers through the use of wetwell airspace divider partitions. The partitions extend to below the water level of the suppression pool so that the gas in one airspace chamber cannot communicate with another airspace chamber. Each wetwell airspace chamber can be placed in flow communication with the drywell via a respective open vacuum breaker. When one vacuum breaker fails in the open position or when wetwell/drywell steam bypass leakage into one chamber occurs, the pressure differential between the wetwell airspace chamber and the drywell drops. However, because the leaking chamber is isolated, the pressure differential between the drywell and the other chambers is unaffected. Thus, the PCC heat exchangers corresponding to non-leaking chambers can continue to operate effectively, even if the PCC heat exchanger corresponding to the leaking chamber is rendered ineffective.