The Nuclear Regulatory Commission is reporting an equipment failure of "high safety significance" at the Browns Ferry Nuclear Plant in Alabama.

The NRC will increase inspection and oversight at the three-reactor TVA plant, located about 100 miles south of Nashville, Tenn., as a result, the agency said.

The failure is linked to a coolant injection valve that failed to open on Oct. 23 last year. Operators were attempting to use a residual heat removal shutdown cooling system during refueling of one reactor. A later investigation revealed that the valve was not confirmed to have worked since March 12, 2009.

The system is important for core cooling during certain accident scenarios, and the valve failure could have damaged the core if an accident with "a series of unlikely events occurred," according to the NRC. Because there was no emergency, there was no danger to the public.

"The valve was repaired prior to returning the unit to service and Browns Ferry continued to operate safely," said Victor McCree, NRC Region II administrator. "However, significant problems involving key safety systems warrant more extensive NRC inspection and oversight" (Nashville Tennessean, May 10). -- JP