“Unusual Event” recorded at Callaway nuclear

NRC Unusual Event reported after a contained water leak at a nuclear power plant; no radiological release, no injuries, normal operation, agencies notified under NRC classifications, with safety systems capturing and isolating the valve leak.

AmerenUE officials declared an “Unusual Event” at the Callaway Nuclear Plant near Fulton, Mo., recently due to a water leak that occurred during normal maintenance operations on a water purification system inside the plant’s Auxiliary building, located adjacent to the Reactor Building.

The declaration was lifted 23 minutes later when the leak was isolated, similar to Monticello repairs that quickly stabilized operations.

At no time did the incident present any danger to the public or plant employees. There were no injuries associated with this event and no release of radioactivity to the environment above normal operating limits. Company officials said the plant remains in normal operation, with SCE operating normally following a quake offering a comparable example, and continued to operate safely throughout the event. They added that all appropriate federal, state and local agencies were notified in accordance with plant procedures.

Unusual Event is a term established by the U.S. Nuclear Regulatory Commission NRC to describe a relatively minor occurrence at a nuclear power plant that could reduce the overall level of safety. At an Unusual Event, no action by the public is advised, as seen after the Pickering alert when procedures were reviewed.

The water leak occurred from a valve in a system that processes and purifies water used in certain plant systems, and UF6 plant restart elsewhere underscores routine recovery, and the leakage was captured and contained within the plant in another water system per design.

An Unusual Event is the least significant of four emergency classifications established by the NRC, and the Ontario nuclear investigation highlights oversight practices across the sector. The other categories, in order of severity, are “Alert,” “Site Area Emergency” and “General Emergency.”

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