Operational Data Collection and Analysis for Risk-Informed Activities
The purpose of this poster is to inform interested stakeholders on the methods and uses of operational and component reliability data collection and analysis performed by the U.S. Nuclear Regulatory Commission (NRC) in support of risk‑informed decisionmaking.
Nuclear plant operational data activities support both the NRC staff and the nuclear industry. A number of NRC oversight programs use the data from the Office of Nuclear Regulatory Research (RES) data collection program to monitor industry performance. In addition, the nuclear industry has access to the same generic data that they use in the preparation and analysis of their in‑house risk assessment activities. These activities support risk‑informed initiatives, such as risk‑informed containment leak rate testing and provide them with an understanding of the parameter values used by the staff in their confirmatory evaluations.
Data collection and analysis activities sponsored by RES also support the NRC’s Standardized Plant Analysis Risk (SPAR) risk analysis models, which cover all operating U.S. commercial nuclear power plants. These activities are performed for the NRC by the Idaho National Lab (INL). SPAR models support risk‑informed decisionmaking, for example: by the Accident Sequence Precursor program, which uses the SPAR models to identify potential precursors; by supporting the agency’s Significance Determination Process risk‑informed evaluations; and by providing an independent review and confirmation of licensee risk analyses submitted in support of risk‑informed initiatives, such as license amendment requests.
To ensure that the SPAR models are up‑to‑date with the most recent industry experience, RES, through INL, collects and analyzes current operating data across the nuclear industry. The data are used to estimate generic inputs to the models. Examples of basic SPAR model inputs derived from the data collection effort are initiating event frequencies, component failure probabilities, component failure rates, maintenance unavailability, and common‑cause failure parameters.
Data sources include licensee event reports, licensees’ monthly operating reports, and the Institute of Nuclear Power Operations’ Industry Consolidated Event System data collection system. The data are stored in a database maintained at INL, depicted below.
In addition to supporting the SPAR tool, the NRC uses the operating experience data it collects and analyzes to support other established regulatory programs, which help identify potential safety issues, such as the Industry Trends Program (ITP). RES supports the ITP by providing the operating experience data used in the trends. Summaries of the data are made available on the NRC public Internet site, http://nrcoe.inel.gov/resultsdb. Also included is support for the Baseline Risk Index for Initiating Events, a measure reported by NRR and used to provide a risk‑informed performance indicator for potential initiating events. This information supports the NRR affirmation that operating reactor safety is being continually maintained and it also helps inform NRC inspectors of recent trends in key front‑line safety systems.