Containment Negative Pressure Evaluation

The decrease in containment pressure following inadvertent actuation of the containment sprays has been evaluated. The depressurization occurs in two definite phases involving the short-term depressurization due to mass transport and the long-term depressurization due to heat transfer. Either phase may determine the maximum depressurization. Simple models may overestimate the maximum depressurization by 50% or more; therefore, transient models are needed to avoid unnecessary conservatism.