Report to Congress on Abnormal Occurrences – Fiscal Year 2020 (NUREG-0090, Volume 43)

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Publication Information

Manuscript Completed: June 2021
Date Published: June 2021

Office of Nuclear Regulatory Research
United States Nuclear Regulatory Commission
Washington, DC 20555-0001

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Section 208 of the Energy Reorganization Act of 1974, as amended (Public Law 93-438), defines an abnormal occurrence (AO) as an unscheduled incident or event that the U.S. Nuclear Regulatory Commission (NRC) determines to be significant from the standpoint of public health or safety. The Federal Reports Elimination and Sunset Act of 1995 (Public Law 104-66) changed the AO reporting frequency from quarterly to annually.

This report describes seven events in Agreement States and two events involving NRC licensees that were identified as AOs during fiscal year 2020. These events are based on the criteria defined in the NRC Policy Statement on “Abnormal Occurrence Reports,” issued in Volume 82 of the Federal Register (FR), page 45907 (82 FR 45907; October 2, 2017). Eight AOs were medical events as defined in Title 10 of the Code of Federal Regulations Part 35, “Medical use of byproduct material.” There was one AO that was a human exposure event.

Agreement States are those States that have entered into formal agreements with the NRC, in accordance with Section 274 of the Atomic Energy Act of 1954, as amended (AEA) (Public Law 83-703), to regulate certain quantities of AEA material at facilities within the States’ borders. Currently, there are 39 Agreement States.

Appendix A, “Abnormal Occurrence Criteria,” to this report presents the NRC’s criteria for identifying AOs. In addition, the NRC identified four events during fiscal year 2020 that met the guidelines for inclusion in Appendix B, “Other Events of Interest.” The first of these events was a human exposure event with possible internal contamination. The second event involved a gauge failure that resulted in unintended exposure to seven individuals, three of whom were classified as radiation workers who received occupational radiation exposure below regulatory limits. The third event was a stuck source event that resulted in an exposure above the regulatory annual limit to an individual involved in recovering the source. The fourth event concerned an extended loss of offsite power event at a commercial nuclear power plant. No events met the guidelines for inclusion in Appendix C, “Updates of Previously Reported Abnormal Occurrences.” Appendix D, “Glossary,” defines terms used throughout this report. Appendix E, “Conversion Table,” presents conversions commonly used when calculating doses. 

Page Last Reviewed/Updated Wednesday, June 02, 2021