Development of Probabilistic Risk Assessment Framework for Utilization of Data. TMI-2 Technology Transfer Contract. Task 3 Final Report

摘要

This study has adapted the techniques of probabilistic risk assessment (PRA) into a framework to help define areas where the results of TMI-2 planned of potential research could be used to reduce the risk of operating a nuclear power plant. In this study, effort was concentrated on ways to improve the ability of a power station to recover from events that have the potential to lead to accident sequences that could involve severe core damage or even core melt with subsequent vessel and containment failure. The underlying philosophy is that of risk reduction through reducing the probability that an accident sequence will progress to severe core damage. The study has demonstrate how probabilistic modeling of accident sequences, using event tree and fault tree logic models, can be applied to quantify the importance, during the course of an accident, of having available various instrument readings and operating fluid systems, and of various operator actions that could be taken. From such quantification, a priority ranking for gathering system and instrument information can be derived. Furthermore, such logic models coupled with a knowledge of the progression of physical processes such as time of core uncovery, release of radionuclides to the containment, onset of containment sprays, etc., can be used to specify which systems should be examined for survivability in adverse environments. The PRA framework could also be be applied to evaluate the efficacy of present and proposed emergency operating procedures. Finally, the information potentially available from TMI-2 can be used to improve PRA modeling of accident sequences and thereby benefit the industry. 53 refs., 21 figs., 22 tabs. (ERA citation 10:039322)