On June 10, 1995, an offsite grid disturbance caused the main generator and reactor at the Waterford nuclear plant outside New Orleans, Louisiana to automatically shut down. An auxiliary operator in the turbine building called a control room operator to report heavy smoke. The control room operator asked the auxiliary operator if he saw flames. The auxiliary operator responded that the smoke was too heavy to see any flames. Two more auxiliary operators were dispatched to the turbine building to investigate the cause of the heavy smoke.
Twenty-nine minutes after the smoke was reported, an auxiliary operator reported flames above the electrical switchgear (i.e., a nuclear plant’s equivalent of a home’s fuse and breaker panel). The fire alarm was initiated. The plant’s fire brigade was unable to suppress the fire using portable extinguishers. A call went out to the local fire department.
The fire department arrived twenty-three minutes later. The plant’s fire brigade leader did not allow the fire department to use water on the fire. He feared putting water on energized electrical equipment. Twenty minutes passed with little progress in combating the fire. The fire brigade leader then approved the use of water on the fire. The fire was then put out within four minutes, or seventy-seven minutes after heavy smoke was first reported.
After the dust (and ashes) settled, it was learned that appropriate fire alarms had actuated in the control room almost immediately. These alarms were not heard over the din from all the other alarms sounding after the shutdown caused by the grid disturbance. The fire alarms were not seen because they were on a cabinet behind the main control panels. The operator did not bother to check this cabinet before sending two auxiliary operators into the burning building to look for flames that the first auxiliary operator could not see due to the heavy smoke.
The worst nuclear plant fire in U.S. history, at Browns Ferry in 1975, burned for over six hours as detailed in Fission Stories #16. The local fire department showed up at Browns Ferry within an hour and recommended using water, but the plant manager refused. Hours later, the fire was finally extinguished within minutes after water was authorized. The NRC’s investigators discovered that the fire brigade had been trained not to use water on electrical fires except as a last resort. One of the key lessons learned from the Browns Ferry fire was to use water to put out electrical fires.
Apparently, the lifetime for lessons learned from the Browns Ferry fire is less than 20 years. The fire brigade at Waterford repeated the very same mistake made by the fire brigade at Browns Ferry. Fortunately, the consequences were not as high this time. But again, luck rather than skill is playing too large a role in nuclear safety.
On March 28, 2010, two fires occurred at the HB Robinson nuclear plant in South Carolina. In the second fire, the workers who first detected it attempted to notify the control room operators. Unable to contact them by radio, the workers attempted to put out the fire. As in the Browns Ferry fire, the delayed notification also delayed the arrival of trained firefighters and extended the fire’s duration.
Two wrongs don’t make a right. The point of that cliché is not to figure out how many wrongs it does take, as the nuclear industry seems to be doing with fire safety. There’s simply no excuse for repeating mistakes learned so long ago at such high cost.
“Fission Stories” is a weekly feature by Dave Lochbaum. For more information on nuclear power safety, see the nuclear safety section of UCS’s website and our interactive map, the Nuclear Power Information Tracker.