Oyster Creek back online after 'cold shutdown'

'Very low levels' of

radioactive steam released

into atmosphere, NRC says

BY PATRICIA A. MILLER

Staff Writer

LACEY TOWNSHIP - Plant operators at the Oyster Creek Nuclear Generating Station faced some "challenges" recently after an electrical fault in a pump motor triggered an automatic shutdown, a Nuclear Regulatory Commission spokesman said.

The water level in the reactor vessel dropped after one of the three feed-water pumps failed, resulting in what NRC spokesman Neil A. Sheehan called "a cold shutdown."

"It [the water level] was still 100 inches plus above the reactor core," Sheehan said. "They have systems that can inject large quantities of water into the reactor vessel very quickly. When you hear low level, that doesn't mean the water was anywhere close to the fuel. There was still ample margin above the fuel pool."

The incident occurred at 5:22 a.m. July 17, when plant operators received a signal of a low water level in the reactor, Sheehan said.

"They didn't have to declare an unusual event or alert, nothing along those lines," he said. "They did have some challenges as they were shutting down the reactor unit."

The isolation condenser system was used to cool down the steam coming from the reactor. That resulted in the release of condensate that contained trace amounts of radioactive tritium released into the atmosphere, Sheehan said.

The released steam had "very low levels of radioactive contamination," Sheehan said, "to the point where if you stood at the plant's fence line, you wouldn't be able to detect anything above background radiation."

NRC officials estimated that roughly 1.05 curies of tritium was released. That translates into a worst-case off-site dose of about 0.005 millirem, which is about 3,000 times less than the annual organ limit of 15 millirem and 25 millirem total body.

Normally when a nuclear plant has a similar shutdown, the isolation condensers are not needed, Sheehan said.

"It's actually a very effective part of their system," he said. "But we would consider it to be complications to what they normally have to contend with during a shutdown."

Oyster Creek was operating at 70 percent power as of press time on Monday.

"The company is troubleshooting some vibration issues affecting the pump that caused the shutdown last week," Sheehan said. "It will need to resolve those issues before ascending to 100 percent power."

There was no danger to the public during the incident, Sheehan said.

"No, the bottom line is that the operators responded appropriately and were able to safely shut down the plant," he said. "The plant's safety systems functioned the way they are designed to operate."

The incident will not be considered as part of AmerGen's quest for the plant to be relicensed for another 20 years, Sheehan said.

"Day-to-day operations are covered under the reactor oversight process," he said. "This will be looked at as part of the ongoing assessment of plant performance."

The NRC is continuing to assess plant operators' response to the incident, he said.

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

A number of organizations and activist groups have opposed the plant's relicensing. Its current license expires in 2009. A coalition of six organizations filed a contention earlier this year that cited concerns about corrosion in the plant's dry-well liner.

The NRC's Atomic Safety and Licensing Board (ASLB) ruled on June 19 that AmerGen Energy Co. had failed to satisfy the standards to grant a summary disposition of the contention. It was the first time in the NRC's history that the ASLB agreed to hear a contention, Sheehan said.

The ASLB's decision means there will be a full public hearing on the dry-well corrosion monitoring issue on Sept. 24 in Toms River.

The state Department of Environmental Protection in June faulted both AmerGen and the NRC for relying on environmental studies that were up to 30 years old, during the relicensing process.

There was no mention of the July 17 shutdown incident on Oyster Creek's Web site as of press time. The last press release was dated Feb. 15, 2007. The release was titled "Oyster Creek cares, contributions total $297,000 to local charities, organizations in 2006."