Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, April 25, 1993 TAG: 9304250047
SECTION: VIRGINIA PAGE: C5 EDITION: METRO
SOURCE: Associated Press
DATELINE: RICHMOND LENGTH: Medium
The valve in a steam line outside the North Anna Power Station's nuclear reactor malfunctioned about 5:30 a.m., damaging housings on the pipe and sending a fine cloud of insulation into the air, Virginia Power spokesman Jim Norvelle said.
The utility at first reported that the pipe had ruptured, spilling slightly radioactive steam. But Norvelle said workers apparently mistook the insulation dust for steam. They shut down the reactor and declared an alert.
"There was no leak, there was no pipe failure as originally thought," Norvelle said.
The accident caused no injuries, he said.
A very small amount of radioactivity was released when power station workers later vented a portion of the steam line, Norvelle said. The venting is routine after a shutdown, he said.
"It's very small, certainly not dangerous," he said.
"We don't have any safety or health concerns, but naturally we are concerned any time there occurs this type of action," said Janet Clements, spokeswoman for the Virginia Department of Emergency Services.
An alert is the Nuclear Regulatory Commission's second-lowest classification for nuclear accidents. The alert was lifted about 8 a.m.
The valve, which ordinarily remains open, apparently began opening and closing rapidly, Norvelle said. The action caused vibrations strong enough to be felt by Virginia Power employees in a control room some distance away, Norvelle said.
"They saw and felt what they believed was a steam leak, and they reported it properly," he said.
The power station's Unit 2 reactor will remain shut for several days while workers repair the damage and try to find out what went wrong with the valve, Norvelle said.
Even if the 16-inch pipe was leaking, the utility would not necessarily have to call an alert, Norvelle said. He called the move "a precautionary measure."
NRC officials stationed at the plant monitored the accident and the agency sent two additional inspectors from a regional office in Atlanta, the agency said in a statement.
The malfunction occurred in an above-ground pipe that transports superheated water between a condenser and a generator, Norvelle said. Although the pipe is outside the building housing the power station's nuclear reactor, the steam retains a small amount of radioactivity.
The power station, 50 miles north of Richmond, serves central and Northern Virginia.
by CNB