Oyster Creek Restarts After Almost Week-Long Shutdown

Patricia A. Miller

The Oyster Creek Nuclear Generating Station is back online, after nearly a week-long unplanned shutdown to repair the electrical system that regulates steam to turn the plant’s turbines, an Exelon spokesman said.

“After repairs were completed, technicians inspected and tested the electrical system before returning the unit to service,” said David Tillman.

Oyster Creek had another unplanned shutdown - also known as a scram - on March 22.

Oyster Creek was already under additional Nuclear Regulatory Commission oversight in 2014 because of a “White” (low to moderate safety significance) performance indicator that stemmed from four unplanned shutdowns, or scrams, in 2013 and 2014.

The NRC ’s performance indicator for unplanned scrams for each 7,000 hours of operation changes from green to white if a nuclear plant has more than three unplanned shutdowns. Oyster Creek crossed the green/white threshold on July 11, 2014, when the plant had a fourth unplanned shutdown, the NRC has said.

The NRC conducted a supplemental team inspection at Oyster Creek from Dec. 8 through Dec. 11.

The NRC found that Exelon had performed an adequate root cause evaluation for the four unplanned shutdowns and a collective root cause evaluation for all of the events, said Ho K. Nieh, Director of the NRC’s Reactor Projects Division in a March 4 letter to Bryan Hanson, Exelon’s President and Chief Nuclear Officer.

The NRC inspectors were satisfied with Exelon’s corrective actions to address the causes of the scrams and closed out the white performance indictor and returned it to green, according to the letter.

The NRC has not reached a final decision on two apparent violations for the plant: A preliminary “White” inspection finding involved emergency diesel generator maintenance and a preliminary “Yellow” (substantial safety significance) inspection finding involving the plant’s electromagnetic relief valves. The final determinations on those apparent violations could result in changes to the NRC’s level of oversight at Oyster Creek, Nieh said in the letter to Hanson.

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