Operating Reactor Scram Trending
The NRC operating experience program tracks several trends of interest, including scrams at commercial nuclear power reactors in the United States. A scram is the sudden shutting down of a nuclear reactor, usually by rapid insertion of control rods, either automatically or manually by the reactor operator. Scrams are also commonly known as a "reactor trip". If you have any comments or questions, please Contact Us.
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Operating Reactor Scrams Dashboard
The Operating Reactor Scrams Dashboard is an up-to-date, interactive database of scrams tracked by operating experience staff since 2011. The dashboard allows the user to use various filters, slicers, and visualizations using the Microsoft® PowerBI® software platform to investigate the overall trends with regard to:
In addition to these capabilities, the user has access to each scram report via links to the reports on the NRC Event Notifications webpage. The Scrams Dashboard is embedded below. Click on the "Open in full-screen" button at the bottom right of the dashboard to view it in full screen.
Assumptions and Description of Analysis
This data includes scrams for commercial operating reactors in the United States since 2011. The data includes scrams at plants that have ceased operation in the time frame displayed. To compile this data, NRC staff review each event report submitted under 10 CFR 50.72, “Immediate notification requirements for operating nuclear power reactors,” and 10 CFR 50.73, “Licensee event report system,” to determine if the event provides operating experience, including unplanned rapid shutdown in response to an unexpected issue. In its review of these reports, NRC staff use considerations such as: 1) whether the reactor was critical at the time of the scram; 2) whether it was a planned shutdown; and 3) whether it was in response to a degraded plant condition. In some cases, such as concurrent reporting of an unusual event under 10 CFR 50.72, the original report filed with the NRC Headquarters Operations Center may not directly reference the reporting code for a scram. In other cases, the data is not definitive as to whether the reactor was critical, or the degree to which the shutdown was planned in advance. There are guidelines for reporting scrams to the NRC under both the regulatory notification requirements referenced above and for assessment purposes as part of the Reactor Oversight Process Performance Indicators, which are also available on the NRC website. While there is considerable overlap between those scrams and what is counted on this board, the events presented here are for informing operating experience and trend analysis, and may not meet reporting requirements for these other regulatory processes. The dataset supporting this dashboard provides a column that tracks instances where the 10 CFR 50.72 report and the events counted in this dashboard differ.