摘要: The probability that reactivity feedbacks fail to prevent damage is computed by propagating data and modeling uncertainties through transient calculations, with these uncertainties being constrained by experimental evidence. Scree... 展开 The probability that reactivity feedbacks fail to prevent damage is computed by propagating data and modeling uncertainties through transient calculations, with these uncertainties being constrained by experimental evidence. Screening processes are used to identify the most important parameters and accident initiators. The response surface method is used to facilitate the error propagation and a Monte Carlo rejection technique is used to force the parameter variations to be consistent with the observed distribution of experimental quantities. The reliability of the failure probability estimates is evaluated. This process is applied to ATWS events in the PRA for the EBR-II reactor. The loss-of-normal-power (LONP), loss-of-flow and transient overpower accidents without scram were found to warrant detailed analysis and a complete analysis has been made for the first of these. Six parameters are primarily responsible for the LONP outcome variations. The conditional probability of minor core damage from LONP without scram is 1.2 (times) 10(sup (minus)2). The uncertainty in this estimate is a factor of 2. This damage estimate would be an order of magnitude higher if experimental information about feedbacks in EBR-II was not used. the conditional probability of major core damage from LONP without scram is <10(sup (minus)6). 20 refs., 1 fig., 3 tabs. 收起