Shearon Harris Design Flaw Brought N.C. Dangerously Close to Nuclear Disaster

A year-long problem with the emergency cooling system at the Shearon Harris nuclear power plant near Raleigh brought North Carolina dangerously close to nuclear disaster in the early 1990s -- and the problem remained hidden from the public until last week. The revelation comes as the world marks tomorrow's 20th anniversary of the Chernobyl nuclear power plant disaster in the Ukraine.

The Harris flaw caused valve and pipe failures that rendered the emergency cooling system inoperable, and it went unnoticed until a refueling outage in 1991, according to a new report from Greenpeace titled An American Chernobyl: Nuclear Near Misses at U.S. Reactors Since 1986. If the Harris plant's primary cooling system had broken down during the malfunction, the emergency cooling system would have been unable to protect the reactor from overheating and releasing large amounts of radiation. The flaw increased the risk of a reactor meltdown by a thousandfold, according to Nuclear Regulatory Commission calculations cited by Greenpeace.

The Harris malfunction ranked among the most significant near misses at U.S. nuclear power plants, tying for first place with a 2002 problem at Ohio's Davis Besse plant that involved a football-sized hole in the reactor vessel, the report says. There were a total of four near misses at Harris, the third-most at any one plant; the others involved fire hazards and problems with heat removal systems. In all, Greenpeace documented a total of 200 near misses at U.S. nuclear power plants since the Chernobyl disaster.

"If any of these 'near misses' had progressed to a meltdown, the government regulators have little confidence that any of the nuclear reactor containments would survive," the report states.

A flaw by Harris plant designer Westinghouse led to the problem with the emergency cooling system. After Westinghouse alerted several nuclear plants about the defect, Harris owner CP&L, now Progress Energy, attempted to correct the problem but unwittingly made it worse. Progress earlier this year announced that it had selected Westinghouse to possibly build two more reactors at the Harris site.

The Durham-based nuclear watchdog group N.C. Waste Awareness and Reduction Network says Greenpeace's discovery shows Progress needs to be more open with the public about problems and how the utility corrects them.

"This is dramatic evidence that major system failures do occur at nuclear plants," according to a statement from N.C. WARN Executive Director Jim Warren. "It shows that the utilities and NRC do not have everything under control, and that they gamble on the public not finding about these problems -- instead of explaining them."

Warren also questions why the system failure persisted for a year without CP&L rechecking the correction it made after Westinghouse reported the defect.

N.C. WARN this week will publish a report on serious and ongoing safety problems at Harris. The group is also holding a forum commemorating the Chernobyl disaster on Wednesday, April 26, from 7 to 9 p.m. at McDougle Middle School, 900 Old Fayetteville Rd. in Carrboro. Mary Olson, director of the Nuclear Information and Resource Service's Asheville office, will speak on what happened at Chernobyl. The forum will also consider the Harris safety problems and the adequacy of the plant's evacuation plan.