Synthesis of experience data for risk assessment and design improvement of gas-cooled reactors

This paper illustrates the practical synthesis of previous component and system operating experience into the reliability parameters which are used in probabilistic risk evaluations of gas-cooled reactors (GCRs). Component and system reliability operating experience provides the basic input data for quantifying event tree and fault tree models that describe hypothesized reactor accident sequences. It is therefore necessary to collect and review the existing operating experience described in numerous accounts of power plant operations for both the development of detailed accident models and the quantification of their likelihood. It was found that the presently available operating experience includes enough information to provide both the qualitative and quantitative understanding necessary to evaluate the safety of the gas-cooled reactor designs