Federal regulators are stepping up inspections at a nuclear power plant in Alabama after deciding an equipment failure there was a serious safety issue.

The U.S. Nuclear Regulatory Commission issued a so-called red finding Tuesday against the Tennessee Valley Authority's Browns Ferry Plant near Athens, Alabama. The NRC issues red findings for problems it believes are of high safety significance.

TVA officials say the problem has been repaired and it was never a safety threat.

The problem centers on a cooling system at the Browns Ferry Unit 1 reactor. NRC officials said a valve on that system failed to open in October 2010 while workers were refueling the reactor. The failure of that valve could have meant the cooling system would not work properly in an emergency.

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