A probabilistic analysis of LWR steam explosions

In this paper, we present a probabilistic assessment of containment failure due to an in-vessel explosion following a core melt accident in a Light Water Reactor. We limit our assumptions to the most basic physical parameters of the core melt accident and describe these parameters with frequency distributions. A Monte Carlo solution technique is used to calculate output frequency distributions for steam explosion energy, reactor vessel response, and resulting missile velocities. Based on current results, we estimate the probability of containment failure due solely to an in-vessel steam explosion to be one to two orders of magnitude smaller than the probability calculated in the Reactor Safety Study (WASH-1400)