The Probability of Liner Failure in a Mark-I Containment, Part I: Probabilistic Framework and Results

An integrated analysis of Mark-I liner attack in a postulated core-melt accident is presented. The approach consists of the mechanistic treatment of the sequence of physical phenomena that lead to liner contact by corium debris and their coupling through a probabilistic framework that allows representation of uncertainties. A physically consistent treatment in each sequence is emphasized, but qualitatively different scenarios to represent the range of behavior due to model uncertainties are allowed. The results are presented in a format that allows their direct use in probabilistic risk assessments; in particular, expert opinion is incorporated by a new methodological approach that involves expert review of, and comment on, a fully documented study all under one cover. The study itself is presented in three parts here; the expert inputs can be found in NUREG/CR-5423.