PRELIMINARY SAFETY SIGNIFICANCE DETERMINED FOR
REACTOR HEAD DAMAGE
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The plant, which has been shut down since February of last year to inspect the reactor vessel head, and entered an extended outage upon the discovery of head corrosion, is operated by FirstEnergy Nuclear Operating Co. It is located near Oak Harbor, Ohio.

Under its safety significance determination process, NRC officials classify inspection findings at nuclear power plants as being one of four colors which delineate increasing levels of safety significance, beginning with "green" and progressing to "white," "yellow" or "red." A “red” category indicates high safety significance.

Utility inspections after the reactor was shut down found evidence of cracks in tubes which pass through the top of the reactor vessel. During repairs to one of the tubes, plant workers found a cavity in the reactor vessel head next to the tube which was later determined to have been caused by boric acid corrosion to a portion of the steel head.

Under the agency’s Reactor Oversight Process, a “red” finding would result in strong actions by the NRC to improve plant performance, including development of a performance improvement plan by the utility and follow-up NRC inspections.

In the case of Davis-Besse, however, the NRC implemented its procedure for plants in extended shutdown with performance problems and established a special NRC Oversight Panel to coordinate the agency’s response to the performance problems which led to the reactor vessel head damage. The Oversight Panel has established a list of extensive actions to be taken by the utility to demonstrate that plant safety systems will perform as designed and that the plant’s safety culture and management problems have been addressed. The NRC is performing extensive inspections to verify adequate implementation of these actions. The Davis-Besse plant may not resume operations until the NRC is assured that it can operate safely.

The utility has 10 days to respond to the NRC’s preliminary assessment. It may ask for a regulatory conference to discuss the finding or it may submit its response in writing.

The NRC documents reviewing its preliminary assessment of the safety significance will be available on the NRC’s web site: http://www.nrc.gov - select “Davis-Besse” from the key issues menu. The documents will be posted on the “News and Correspondence” page.

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Thursday, February 22, 2007