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A risk advisory system,(RAS) also known as a safety or risk monitor, is an on-line, plant-specific, real-time analysis tool used to determine the instantaneous plant risk based on actual status of systems and components. A RAS is based on a nuclear power plant’s current as-built, operated, and maintained configuration and reflects the status of plant components (e.g., any components out-of-service for maintenance or testing). The underlying RAS model is consistent with the plant’s living probabilistic risk assessment (PRA) and is updated with the same periodicity. The RAS makes it possible for plant staff to easily examine past operating practices, current plant conditions, and future planned activities (e.g., maintenance schedules). This is accomplished by providing an easy-to-use interface consistent with terminology and nomenclature familiar to plant staff. The RAS makes the PRA model and resulting insights available to non-PRA analysts (i.e., it "mainstreams" the PRA to those actually operating and maintaining the facility). The result is plant personnel who are risk-aware and who more thoroughly consider impacts to safety from past, current, and planned activities.

The technology and applications of RASs are not new. Development of the technology began in the early 1980s, with the first true RAS installed in 1987 at Heysham Unit 2 in the United Kingdom. Further technology development and refinement eventually led to two commercially available RASs that began to be installed in U.S. plants in the mid-1990s. At present, RASs are installed at more than 100 plant sites in at least eight countries. In addition, the U.S. Nuclear Regulatory Commission recently licensed a RAS for use in training the commission’s inspectors in PRA and PRA applications.