Cladding failure probability modeling for risk evaluations of fast reactors

This paper develops the methodology to incorporate cladding failure data and associated modeling into risk evaluations of liquid metal-cooled fast reactors (LMRs). The methodology is applied to the analysis of the probability of core-disruptive coherent cladding failure in the response of metal-fueled LMRs to anticipated-transient-without scram (ATWS) initiators. Calculations are presented for the transient overpower event which produces the most severe long-term temperatures. Two cladding types with different failure mechanisms are investigated. Also, a range of discrete accident recovery times over which operator intervention could terminate the accident progression are considered. The results of the cases studied indicate that inherent shutdown mechanisms avert core disruption with very small change of failure for either cladding type. (author)