Key Issues
Nuclear Power Plant Fire Protection
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Browns Ferry Fire
In the 1960s and early 1970s, local fire protection codes, generally the same required of other industrial facilities, governed nuclear plants.
On March 22, 1975, workers at the Browns Ferry plant in northern Alabama were using a candle to check for air leaks at openings in a wall where trays of electrical cables passed from one room to another. As a worker held a candle near one of the openings, the flow of air drew the flame toward polyurethane foam used to seal the openings. The foam ignited and spread fire along the cables. As the cable insulation burned, the fire eventually shorted out the plant’s backup safety systems.
Workers tried to extinguish the fire, without success, and notified the control room. Shortly afterward, a municipal fire department arrived at the scene. Operators manually shut down both reactors and kept the plant in a safe condition throughout the incident. However, several factors hampered firefighting efforts, including a shortage of emergency breathing gear and plant operators’ reluctance to use water in electrical areas. Local authorities did not declare the fire “out” until more than seven hours after it started.
Four days later, the NRC appointed a panel to study the incident. Its February 1976 report identified a number of needed improvements in fire protection programs. Citing “the defense-in-depth” approach toward plant safety, however, the report found that public health and safety were protected during the incident, despite significant shortcomings in fire protection.
The report established that the three hallmarks of nuclear plant fire protection are to:
Browns Ferry Fire
In the 1960s and early 1970s, local fire protection codes, generally the same required of other industrial facilities, governed nuclear plants.
On March 22, 1975, workers at the Browns Ferry plant in northern Alabama were using a candle to check for air leaks at openings in a wall where trays of electrical cables passed from one room to another. As a worker held a candle near one of the openings, the flow of air drew the flame toward polyurethane foam used to seal the openings. The foam ignited and spread fire along the cables. As the cable insulation burned, the fire eventually shorted out the plant’s backup safety systems.
Workers tried to extinguish the fire, without success, and notified the control room. Shortly afterward, a municipal fire department arrived at the scene. Operators manually shut down both reactors and kept the plant in a safe condition throughout the incident. However, several factors hampered firefighting efforts, including a shortage of emergency breathing gear and plant operators’ reluctance to use water in electrical areas. Local authorities did not declare the fire “out” until more than seven hours after it started.
Four days later, the NRC appointed a panel to study the incident. Its February 1976 report identified a number of needed improvements in fire protection programs. Citing “the defense-in-depth” approach toward plant safety, however, the report found that public health and safety were protected during the incident, despite significant shortcomings in fire protection.
The report established that the three hallmarks of nuclear plant fire protection are to:
- prevent fires from starting
- quickly detect and extinguish fires to limit damage
- design plants to minimize damage to essential functions and ensure safe shutdown.
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