LIMESTONE COUNTY — The Nuclear Regulatory Commission expects to fully inspect Browns Ferry Nuclear Plant in April 2013 to see if TVA has implemented the improvements and procedures required after a valve on a backup fire-protection system malfunctioned in 2010 resulting in a "red finding" safety violation.
On Wednesday, the NRC held a public hearing in which officials discussed TVA's performance and response to the findings -- including the high-level red finding as well as one low-to-moderate risk "white flag" safety finding and two "white flag" performance indicators.The NRC said it had downgraded the three white flags to green - its lowest level - but it will continue to monitor through the first quarter of 2013 the white finding related to safe shutdown.
The red finding -- the NRC's most serious safety violation -- resulted, in part, because employees and inspectors failed to detect the valve problem for up to 18 months despite requirements that the valve be tested quarterly. Since then, TVA has been trying to identify and correct weaknesses in its maintenance and inspections processes at the NRC's request.
TVA officials said Wednesday they had completed 93 percent of the actions required before it can request what is called a "95003 supplemental inspection." It expects to make the request in January. NRC's Eugene Guthrie said Wednesday NRC will likely begin the intense inspection on site in April.
NRC officials said TVA had resolved the lower-level safety issues. These include one white finding at Units 1, 2 and 3; one white performance indicator for unplanned scrams (emergency reactor shutdowns) at Unit 1; and one white performance indicator for a high-pressure injection system at Unit 3.Here is an overview of what the white flags entailed:
Details of safety violations
• The inspection leading to the white finding found that TVA "failed to properly implement the requirements of the plant modifications and engineering change control procedure, which resulted in inadequate training of safe-shutdown instruction procedures." TVA fully addressed this issue by Oct. 11.
• The inspection leading to one of the white performance indicators showed there were unplanned scrams (or emergency reactor shutdowns) on Unit 1 and that the unit was crossing from the white to the green threshold by having "more than three scrams in four quarters." TVA fully addressed this issue by Nov. 16.
• The inspection of the high-pressure injection system on Unit 3, which led to the other white performance indicator, found "high unreliability and unavailability of the HPCI system. It also found "high unavailability due to repetitive stream admission valve leakage along with four functional failures within the past three years." TVA fully addressed this issue by Oct. 17.
As a result on improvements, the NRC has returned the two white performance indicators to green, the lowest level.
As for the white finding, the NRC said that will remain on its monitoring list until the first quarter of 2013.
Check back here later today for more details of Wednesday's meeting.