Modelling uncertainties in steam explosion damage potential

The purpose of this paper is to illustrate the use of rather detailed mechanistic considerations within an overall probabilistic framework aiming to quantify the likelihood of the α-mode (steam explosion induced) containment failure. Previous attempts in this field of application were limited to either judgmental assignment of likelihood in component events (considered independent) or to parametric evaluations; that is, random sampling of certain key parameters (assumed independent) considered as random variables. This approach is based on the consideration of the process as a sequence of mechanistically interdependent events. These events are connected through causal relations which express their correlation not as a simple-valued function, but rather as a band with a given probability distribution. Each of these causal relations is constructed on the basis of numerical experiments. The arithmetic of probabilistically linking these causal relationships is carried out with the method of Discrete Probability Distributions. (orig./HSCH)