A method for developing living PSA for NPPs by using the GO-FLOW methodology

A living PSA method is developed for nuclear power plants using GO-FLOW method. Unlike conventional fault-tree analysis, the GO-FLOW model is a system reliability analysis method based on a success-tree oriented approach, which can treat time-dependent system reliability analysis including phased-mission problems. A generalized GO-FLOW modeling structure is proposed in this paper, where all the necessary functional modes of the equipment comprising a whole system can be taken into account. Moreover the structure of GO-FLOW modeling can be easily modified in accordance with the changes of plant configuration caused by either equipment failures, or operator interventions, or maintenance activities. The methods on how to build up a generalized GO-FLOW model structure and then how to convert it to a living PSA model by utilizing the GO-FLOW model are validated as illustrated by a case study. An application of the proposed method is also briefly discussed for developing to a risk monitoring system. (author)