Dec. 5--YORK -- Federal regulators continued their investigation last week on a series of incidents at Catawba Nuclear Station, and say there is no threat to public safety. Findings are expected to be published within 30 days.

The Atlanta office of the U.S. Nuclear Regulatory Commission sent an inspector to the York facility to examine electrical problems that first occurred during an "unusual event" May 20. On that date, electrical circuits tripped at the plant causing two nuclear reactors to shut themselves down as a safety precaution. The current investigation was set to look into water flowing into electrical penetrations.

"It's just something that we want to make sure they have their hands around, and that we understand it, too," said Roger Hannah, NRC spokesman.

Water from the plant's Unit 2 cooling towers flowed into a diesel generator room, according to the NRC, at which time plant employees determined several electrical conduits and penetrations had degraded seals. During an intense rain in August, water entered the turbine building through unsealed electrical penetrations and accumulated around electrical transformers. Duke Energy has since initiated corrective actions.

But the incident should not alarm residents living near the plant, Hannah said.

"It's not an immediate safety issue," he said.

Working together

The NRC performs regular investigations of nuclear plants, Hannah said, as well as special investigations following incidents, such as the one in May. If there are any violations cited, Hannah said, it would likely be "low level violations."

Any incident similar to the "unusual" one in May must be investigated so the company and commission can work together to eliminate problems, Hannah said.

"Obviously water and electricity are not two things you want to have in close proximity," he said.

Findings also may help prevent future problems at other plants, he said.

Other issues

In November, a separate investigation determined the plant's Standby Shutdown facility was susceptible to flooding from two sources. Catawba's overall response and investigation will be assessed by the NRC.

All the appropriate corrections have been made since the first two incidents, said Catawba spokeswomanValerie Patterson. The recent findings at the Standby facility, which houses emergency equipment and controls for the station, included degraded cable trenches and a degraded door, she said.

"Two are addressed and one, we're working on," Patterson said. "That, for now in the interim, lessens the impact of flooding." She admits, though, the plant has "more work to do," and said "none of them had any affect on plant operations and none of them ever presented a threat to the public,."

For updated information as it becomes available, visit www.nrc.gov.