The two nuclear reactors in Beaver Valley Power Station operated safely last year, but regulators said on Thursday they found four low-level safety violations that utility FirstEnergy Nuclear Operating Co. has remedied.
Nuclear Regulatory Commission officials held a public meeting in the Shippingport Community Building across the street from the 1,000-acre plant to discuss its performance. About 25 people attended.
"These findings were of very low safety significance," said Darrell Roberts, director of the Division of Reactor Projects in Region I, which stretches from Pennsylvania to Maine.
Erin Bonney, an inspector based at the power plant, said that in September an instance of "poor maintenance practice" caused a bolt to come off a ventilation system leading to backup diesel generators. The generators provide emergency power.
She said the other three findings were:
-- An alarm on a main feed pump on the turbine side of the plant was improperly disabled by workers
-- When Unit 1 was being restarted in the fall after refueling, a connecting line to the reactor briefly exceeded the rate at which NRC regulations say it is supposed to heat up
-- Workers misread a procedure and misaligned some safety valves that caused packing leakage, but the water leakage was repaired before the unit restarted.
Each finding was rated "green," Roberts said, the lowest of four possible ratings: green, white, yellow and red.
Ted Robinson of Squirrel Hill-based Citizen Power, a watchdog group, asked officials why the steel-and-concrete containment liners surrounding the reactors varied in thickness in an inspection report submitted by FirstEnergy.
Inspector David Werkheiser said the liner met or exceeded the minimum thickness levels required. As part of a recent 20-year extension of the reactors' operating licenses, FirstEnergy promised to evaluate regularly the thickness of its containment liners.
In April 2009, corrosion and a hole about the size of paper clip were found in the Unit 1 reactor liner while it was shut down for refueling, which occurs every 18 months. The section was removed and replaced with a steel plate.
Separately, NRC officials began a "special inspection" on Monday at a different plant operated by FirstEnergy.
Higher-than-expected radiation levels were detected April 22 at the Perry Nuclear Power Plant 35 miles northeast of Cleveland.
Radiation levels increased as five workers removed a neutron monitor from the reactor and the plant was being shut down for refueling, said NRC spokeswoman Viktoria Mitlyng. She said the workers were not hurt and finished the work. An investigation will take about two months to complete.
Todd Schneider, a FirstEnergy spokesman, said one worker was exposed to 98 millirems of radiation, the equivalent of a few hospital X-ray scans. The NRC has established a dangerous yearly exposure threshold at 5,000 millirems.
