Development and application of a Risk Assessment Tool

Probabilistic Safety Assessment (PSA) is a powerful method for evaluating the safety of nuclear facilities. PSA models are the basis of risk monitors, which can be utilized for monitoring the plant risk. The objective of this work was to develop a risk monitoring software tool, which could match the requirements for a risk monitor, according to standard reference documents. We tried to implement all required features in a user-friendly interface. In this paper a newly developed risk monitor called Risk Assessment Tool (RAT) is presented, and its main features and capabilities are introduced. Some of these features are: graphical event/fault tree developing interface, a 30-day risk profile, performing importance analysis, different administrative levels, and handling time-dependent failure data. In order to have an actual application, a case study is performed for Tehran Research Reactor, and the results are compared to the results obtained from a well-known reliability software package. In most cases, the results from two software tools match well.