The Nuclear Regulatory Commission (NRC) has issued its annual report on abnormal occurrences for fiscal year 2012, citing 21 events involving radioactive materials and one event at a commercial nuclear power plant.
An accident or event is considered an abnormal occurrence if it involves a major reduction in the degree of protection of public health and safety. Abnormal occurrences can include, but are not necessarily limited to, moderate exposure to or release of radioactive material licensed by the NRC or a state agency; major degradation of safety-related equipment; or major deficiencies in design, construction, use of or management controls for facilities or radioactive material at NRC-licensed facilities.
For FY 2012, there was one abnormal occurrence at an NRC-licensed nuclear power reactor. This event occurred in June 2011, at Fort Calhoun Station, with the fire and failure of a safety-related electrical breaker, and the subsequent loss of both trains of safety equipment. The public was never in danger, and there was no release of radioactivity. The NRC later determined that the event warranted a red finding for high safety significance under the agency’s Reactor Oversight Process.
Of the 21 abnormal occurrences involving radioactive materials, one involved exposure of an embryo or fetus, a second involved an exposure to a radiographer, and the remaining 19 events involved misadministration of radioactive material during diagnostic or therapeutic procedures. Thousands of such procedures are conducted in U.S. medical facilities each year. Seven of the abnormal occurrences actually occurred in prior fiscal years, but NRC’s investigations were closed during FY 2012.
The report details investigations of each incident by the NRC, Agreement States and licensees, as well as measures taken to ensure such incidents do not recur.
A section on “other items of interest” discusses eight events that did not meet the criteria to be classified as abnormal occurrences but are included in the report because of high public and media interest. Five of these events occurred at nuclear power plants, one event involved a medical treatment device, one event involved a lost well logging source, and the last event involved a fuel cycle facility.
The report on abnormal occurrences for fiscal year 2012 was initially published in May as NUREG-0090, Volume 35. The report was revised to include editorial corrections and reissued in August as NUREG–0090, Volume 35, Revision 1. Both are available here: Report to Congress on Abnormal Occurrences