The US Nuclear Regulatory Commission has determined that an event at unit 2 of TVA's Browns Ferry nuclear power plant in December 2012 was of 'low to moderate safety significance,' and has cited TVA for not following its procedures.
Unit 2 was running at 100% power on 22 December 2012 when a TVA senior reactor operator opened the wrong breaker on a reactor protection system bus. That caused the unit 2 reactor scram and main steam isolation valves to close.
NRC said in an inspection report that the lack of adequate self-check, peer checking, and pre-job briefing resulted in the operator opening the incorrect breaker.
"After considering the NRC analysis as well as information presented by TVA at [a 24 June] conference, the NRC concluded the failure by a TVA operator to follow procedures should be classified as white, or having low-to- moderate safety significance."
NRC said that since Browns Ferry Unit 2 is already under increased NRC oversight, the finding will not change the level of oversight, but the agency will conduct a supplemental inspection to ensure TVA understands the cause and extent of the issue, and has taken appropriate corrective actions.
"Following procedures is extremely important in nuclear power plants and TVA is making changes in the way procedures are implemented to provide the right checks and balances," said Victor McCree, NRC Region II Administrator.
Photo: Browns Ferry (Source: TVA)