Saturday, April 15, 2000

Saturday, April 15, 2000 Computers shut down at nuclear plant

Safety unaffected by system glitch

By JAMES ELI SHIFFER, Staff Writer

A software glitch knocked out two safety-monitoring computers at the Shearon Harris nuclear plant earlier this month, prompting plant workers to notify state and county officials through a hot line.

The April 2 failure of the Emergency Response Facilities Information System was the 15th since the plant in southwestern Wake County started generating electricity in 1986, but public safety was never threatened by the computer problem, said Mike Hughes, a spokesman for Carolina Power & Light Co., which owns the plant.

The two computers that make up the monitoring system display the core temperature, pressures and other vital signs of the nuclear plant, which is useful for workers stationed outside the control room during emergencies, Hughes said. But plant operators get the same information directly from the gauges, meters, warning lights and monitors in the control room, he said. "This was a computer crash," Hughes said. "There's no off-site safety implication because it is essentially a backup monitoring system." Control of the plant was never affected and the reactor continued to operate, Hughes said. Still, federal safety rules consider any prolonged outage of the system an "unusual event" -- the lowest of four levels of emergency that nevertheless requires notification of public safety officials for the state and the four counties within 10 miles of the plant. The problem began before dawn April 2 when programmers reset the clocks on the two computers to reflect the end of daylight-saving time. When they flipped the power switch just after 5 a.m., the computers refused to reboot, Hughes said. In the past, any shutdown of the system would have triggered an "unusual event" declaration, but starting in 1989, the NRC agreed to give CP&L four hours to get the computers running again before having to notify anyone.

At 9:17 a.m., with the system still down, CP&L alerted the NRC, the state Highway Patrol and emergency-management officials in Wake, Chatham, Harnett and Lee counties. Local officials were updated on the situation every 30 to 40 minutes, said Brian McFeaters, a county emergency planner. One of the two computers came back online about 10:30 a.m., Hughes said, but the other took until midafternoon to fix. At 4:30 p.m., CP&L declared the unusual event over.

It took until April 4 to discover what was wrong, however: When the computers were shut off and restarted, a fault in their shared memory prevented either of them from booting up, Hughes said. Additional programming fixed the problem, he said. "The plant is going into a refueling outage this weekend," Hughes said. "Sometime after the outage, we will meet with the local counties ... and the state and work toward eliminating the ERFIS as an unusual event."

If the officials agree, Hughes said, CP&L will take the proposal to NRC, which has lifted the regulation from the emergency response plans of other plants.

http://www.news-observer.com/daily/2000/04/15/tri10.html

-- Martin Thompson (mthom1927@aol.com), April 15, 2000