NRC to take a closer look at Oyster Creek nuclear plant

The federal Nuclear Regulatory Commission will step up oversight of the Oyster Creek Nuclear Generating Station, since the plant "crossed the threshold" for the number of unplanned shutdowns.

The NRC finished its quarterly review of the nuclear plant, which assesses performance indicators and inspection results, on Oct. 26.

"Our review of Oyster Creek performance identified that you cross the threshold from Green to White for the "Unplanned Scrams per 7000 Critical Hours" performance indicator," James W. Clifford, the NRC's acting director of the Division of Reactor Projects for Region 1 wrote in a letter to Charles G. Pardee, president and chief nuclear officer for Exelon Nuclear, the plant's owner. "This threshold was crossed due to the most recent unplanned automatic reactor scram that occurred on July 12, 2009."

A "white" performance indicator translates into additional NRC oversight. A supplemental team inspection will take place after Exelon completes a root cause evaluation to determine the underlying perform- ance issues, Clifford said.

"This inspection procedure is conducted to provide assurance that the root causes and contributing causes of risk significant performance issues are understood, the extent of condition is identified, and the corrective actions are sufficient to prevent recurrence," Clifford said in the letter.

The most recent unplanned shutdown came on July 12. Plant operators declared an "unusual event" at 1:48 a.m. when a lightning strike resulted in a loss of off-site power to the plant.

Several equipment anomalies were found during the shutdown, including a switchyard breaker that failed to open to clear an electrical fault; an emergency diesel generator that took 80 seconds to start instead of the required seven seconds; and a primary containment isolation occurred because of "low-low" reactor water levels due to the loss of power in the main feedwater pumps, according to the NRC's July 15 unusual event notification.

Oyster Creek also went into cold shutdown on April 25, after one of the plant's two transformers failed. The transformer that failed was a 30-year-old replacement that Exelon brought in in February to replace another transformer that caught on fire on Feb. 2. Plant operators declared an unusual event after the fire.

NRC regulations allow nuclear plants no more than three unplanned shutdowns for every 7,000 hours of operation. Oyster Creek's number of unplanned shutdowns, also known as scrams, was 2.7 during the first quarter of 2009, before the latest shutdown.

NRC Region 1 Administrator Samuel J. Collins had warned during the plant's annual assessment meeting in Toms River last spring that Oyster Creek was close to exceeding the allowable hours of unplanned shutdowns in one year. He made the remarks before the July shutdown.

The white performance indicator status will remain until the plant has operated without additional shutdowns for a sufficient period of time, NRC spokesman Neil A. Sheehan said.

"We will not close out the issue until we are satisfied the underlying issues have been addressed," he said.

The NRC relicensed Oyster Creek on April 8 to operate for another 20 years, much to the dismay of a coalition of citizen groups, who claim the aging plant is unsafe.

Oyster Creek is the oldest nuclear plant in the United States. It went online Dec. 23, 1969.