Delta Force
Banned
The Browns Ferry Unit 1 fire occurred four years before the infamous incident at Three Mile Island. While Three Mile Island has been part of the public imagination for decades, Browns Ferry is virtually unknown, despite being an incident with far more potential for escalation and leading to significant changes for nuclear energy regulation. It occurred at what was then the largest nuclear power station in the world, owned and operated by the United States government owned Tennessee Valley Authority, and involved a failure scenario that had never before been considered, namely a fire in a junction box with control cables for both the Unit 1 and Unit 2 reactors. It remains the second most dangerous incident to have occurred in a United States nuclear power plant, after Three Mile Island itself.
An account of the Browns Ferry fire from Wikipedia:
What would it have taken for Browns Ferry to have become more well-known by the public? Since Browns Ferry did not result in any radiation leakage or fatalities, could the incident help the industry improve safety in a less fearful climate?
An account of the Browns Ferry fire from Wikipedia:
The March 22, 1975 fire started when a worker using a candle to search for air leaks accidentally set a temporary cable seal on fire. At Browns Ferry, foamed plastic, covered on both sides with two coats of a flame retardant paint, was used as a firestop. The fire spread from the temporary seal into the foamed plastic, causing significant damage to the reactor control cabling in the station.[9]
A U.S. Nuclear Regulatory Commission bulletin explained the circumstances of the fire.
The fire started in the cable spreading room at a cable penetration through the wall between the cable spreading room and the reactor building for Unit 1. A slight differential pressure is maintained (by design) across this wall, with the higher pressure being on the cable spreading room side. The penetration seal originally present had been breached to install additional cables required by a design modification. Site personnel were resealing the penetration after cable installation and were checking the airflow through a temporary seal with a candle flame prior to installing the permanent sealing material. The temporary sealing material was highly combustible, and caught fire. Efforts were made by the workers to extinguish the fire at its origin, but they apparently did not recognize that the fire, under the influence of the draft through the penetration, was spreading on the reactor building side of the wall. The extent of the fire in the cable spreading room was limited to a few feet from the penetration; however, the presence of the fire on the other side of the wall from the point of ignition was not recognized until significant damage to cables related to the control of Units 1 and 2 had occurred.[10]
This later resulted in the Nuclear Regulatory Commission making significant additions to the standards for fire protection through the publication of 10CFR50.48 and Appendix R. According to the Nuclear Information and Resource Service, the newly restarted Unit One does not comply with these standards. Unit Three was not affected by the accident. This event was pivotal not just for firestopping in the nuclear field, but also in commercial and industrial construction. While the nuclear field went to installations of silicone foam, a wider array of firestops became prevalent in non-nuclear construction.
In a 2005 analysis of significant nuclear safety occurrences in the US, the NRC concluded that the fire at Browns Ferry was the most likely (excluding the actual Three Mile Island accident) "precursor" incident to have led to a nuclear accident in the event of a subsequent failure.[11]
What would it have taken for Browns Ferry to have become more well-known by the public? Since Browns Ferry did not result in any radiation leakage or fatalities, could the incident help the industry improve safety in a less fearful climate?