Browns Ferry nuclear power plant told the NRC this morning that a recent review had cast doubts on the ability of the facility’s reactors to shut down in the event of a fire in a particular location. According to the Event Report: “Due to lack of physical separation with 120 volt AC lighting circuitry, the RPS (Reactor Protection System) potentially could remain energized due to a postulated hot short circuit during a fire which could potentially prevent the control rods from inserting. Therefore, the fail-safe design of the RPS system would not be maintained.”
This is of particular concern at Browns Ferry, where a major fire occurred on March 22, 1975. A worker using a candle to search for air leaks accidentally set fire to a temporary cable seal. The fire spread to formed plastic and caused extensive damage to the Unit 1 cabling system. The unit was shut for a year while repairs were being made. The accident has been characterized as a “near catastrophe,” and led to significantly tighter NRC fire protection rules.
Despite the doubts, all three reactors at Browns Ferry continue to run at 100 per cent output this morning. Let’s just hope nothing catches fire.
Just a small aside: I don’t want to be too much of a stickler, but the word event is misspelled twice in Browns Ferry’s Event Report, once appearing as vent and a second time as even. I know that I have made mistakes a time or two in this blog, but a little proofreading goes a long way….
Another small aside: The three reactors at Browns Ferry are General Electric boiling water reactors of the type that failed at Fukushima.