DETROIT (Michigan News Source) – On this day in Michigan, 57 years ago, an experimental nuclear power plant in Monroe County experienced a meltdown — kicking off what the University of Michigan called the “worst nuclear accident in the United States before the Three Mile Island disaster.”

The new fast breeder reactor power plant, Enrico Fermi 1, had been uniquely designed to generate more nuclear fuel than it consumed. It used sodium instead of water as a coolant, which posed a risk of explosion when exposed to air or water and limited the amount of time plant operators had to control any mishaps before they turned deadly.

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“The necessity of keeping air from coming into contact with the sodium coolant makes refueling and repairing fast reactors much more difficult and time-consuming than for water cooled reactors,” nuclear researchers wrote in a recent paper, “It’s Time to Give Up on Breeder Reactors.” “Such headaches have contributed to many fast reactors sitting idle a large fraction of the time” — including Fermi 1.

The experimental plant had been operating at full power for less than a year when radiation monitors alarmed, signaling a meltdown that sparked years of controversy over the safety of nuclear power.

According to the U.S. Nuclear Regulatory Commission, a loose plate blocked sodium coolant from reaching the fuel subassemblies, causing them to begin melting. The reactor was manually shut down without elevated radiation escaping the plant. No injuries were reported.

For nearly four years, the reactor remained inoperative while the accident was investigated and the system was repaired. It was then restarted and ran until 1972, when the core was approaching its burnup limit and the reactor was permanently decommissioned.

The incident was commemorated in novelist John G. Fuller’s Reader’s Digest book, “We Almost Lost Detroit,” which Kirkus Reviews said revealed how “a government agency’s forked tongue can damn itself.”

A response to the book, “We Did Not Almost Lose Detroit,” argued that “much of the source information is distorted such that the average reader without technical background could easily be misled to agree with the anti-nuclear stance of the author.”

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Decades later, the Detroit Free Press called the accident “a stark reminder that decisions on how to meet the economy’s energy needs are nearly always controversial and may bring unanticipated consequences.”

According to the NRC, Fermi 1 is now completely contained within the newer Fermi 2 site, a successor nuclear power plant that provides 20% of the total energy DTE produces in Michigan. Fermi 1 is in safe storage, and no spent fuel remains onsite. Major components of the plant, including sodium, the reactor vessel, and piping have been removed.

Besides Fermi 2, located in Newport, there are two other nuclear power plants in Michigan: Cook in Berrien County and Palisades in Covert Township. Palisades is currently closed, but plans have been made to restart it, which would make it the first successfully restarted nuclear power plant in the U.S.

According to the World Nuclear Association, the risk of accidents in nuclear power plants is “low and declining.”

“No industry is immune from accidents, but all industries learn,” the Association wrote in its safety brief. “The novelty value and hence newsworthiness of nuclear power accidents remains in high contrast with other industrial accidents, which receive comparatively little news coverage.”

Still, in the rare event of an emergency, the Michigan government cautions those living within ten miles of a plant to form a plan for sheltering in place or evacuation.

There are four levels of public alert: Unusual Events, which does not imply a radiation leak and requires no action; Alert, which indicates that any possible radiation leaks are contained within the plant; Site Area Emergency, which indicates radiation could be released from the plant at low levels; and General Emergency, which could indicate large amounts of leaked radiation. In the case of the last two, area sirens may sound to alert the public.

Further information about nuclear safety in Michigan is available at MIReady.