The history of nuclear power in the United States has been marked by numerous milestones, many of them bad — accidents, construction snafus, engineering incompetence, etc., etc.
One incident that has cast a long shadow over the nuclear power industry’s claim for safety will be marked on Oct. 5, 1966, when Detroit Edison’s Fermi-1 nuclear plant suffered a partial meltdown, caused by a piece of floating shrapnel inside the container vessel. Not as well known as Three Mile Island, Chernobyl, or Fukushima, but much closer to home.
The Enrico Fermi Nuclear Generating Station was and is still located on the shore of Lake Erie near Monroe, in Frenchtown Charter Township, Michigan, approximately halfway between Detroit, Michigan, and Toledo, Ohio.
The main cause of the temperature increase was a blockage in one of the spigots that allowed the flow of cooled liquid sodium into the reactor. The blockage caused an insufficient amount of coolant to enter; this was not noticed by the operators until the core temperature alarms sounded. Several fuel rod subassemblies reached high temperatures of around 700 °F (370 °C) (with an expected range near 580 °F, 304 °C), causing them to melt.
According to subsequent inspections, no radioactivity escaped to the environment. No injuries were reported inside or outside the plant. The worst case scenario of a “China Syndrome” incident in which melted fuel pooled within the containment vessel and reached critical mass didn’t even come close to occurring.
Nuclear industry apologists long have resented the public attention given to the Fermi-1 meltdown, especially through novelist John G. Fuller’s 1975 book about the case, “We Almost Lost Detroit” (which itself prompted the song of the same name by the late Gil Scott-Heron).
In many ways, the accident underscored the flaws in planning and operation of the industry that have dogged it ever since, all but destroying nuclear power’s reputation as a sustainable energy source that might supplant fossil fuel generation and help combat climate change.
To begin with, it showed how unforgiving nuclear power technology could be. The accident’s cause was trivial, yet it succeeded in shutting down the plant for four years. (Fermi-1 was permanently shut down in 1972, but its successor, the 1,100-megawatt Fermi-2, went online in 1988 and is still operating.) The plant was equipped with elaborate monitoring and alarm systems, yet when these showed unexpected readings, the onsite staff tended to dismiss them as anomalies. A partial meltdown eerily similar to the Fermi incident had occurred at a similar test reactor at Santa Susana, Calif., in 1959, yet the Detroit Edison staff failed to learn from the experience. The Fermi workers “must have remembered this accident pretty well, since they duplicated almost every key aspect of it just seven years later,” David Lochbaum, director of the Nuclear Safety Project for the Union of Concerned Scientists, commented recently.
The Fermi-1 technology was especially complex. The unit was a fast breeder reactor, which used a combined plutonium-uranium core to produce more fuel than it consumed during operation. It was cooled by a flow of liquid sodium, which can explode when it comes in contact with air or water, making “the possibility of sodium leaks a serious problem,” the nuclear expert Daniel F. Ford observed in 1982.
On a larger scale, Fermi-1, like other U.S. reactors, was the product of a government campaign to show that the technology that had destroyed Hiroshima and Nagasaki, Japan, in 1945 could be turned to peaceful uses. Its prime promoter was Lewis Strauss, the fanatically pro-nuclear chairman of the Atomic Energy Commission, who first made the over-optimistic claim that nuclear energy would be “too cheap to meter.” For Strauss, who had President Dwight Eisenhower’s ear, the quest assumed religious overtones. “I believe firmly that our knowledge of the atom is intended by the Creator for the service and not the destruction of mankind,” he wrote in 1955.
The AEC took the lead in fighting concerns about nuclear safety. The commission’s own experts considered siting Fermi only 29 miles from the major population center of Detroit to be a potential “public hazard,” but their report was suppressed. The AEC’s construction permit for the plan was challenged by local unions, whose case went to the U.S. Supreme Court — which ruled that the AEC had sufficient authority to act. The 7-2 decision promoted a thunderous dissent from Justice William O. Douglas, who called the AEC’s permit “a light-hearted approach to the most awesome, the most deadly, the most dangerous process that man has ever conceived.”
The Fermi design showed how haphazard plant engineering could be, even in the face of the dangers. At a late stage of the design, conical “flow guides” were placed on the floor of the core unit. The idea of these pie-shaped structures was to direct the flow of the incoming sodium coolant into the core, and also to ensure that any molten core material would spread out, “lessening the chances of forming a critical mass,” Lochbaum explained.
To shield the flow guides from the heat of molten fuel, they were clad with a layer of heat-resistant zirconium. Yet during operation, two of the covers broke loose and floated around within the system, occasionally obstructing the cooling sodium flow. That accounted for the occasional, anomalous readings of high heat noticed by plant operators. But they couldn’t diagnose the problem until the interior could be inspected, after the damage was done and the plant shut down. That’s when they discovered, as Lochbaum says, that “the good intention of making the plant safer actually compromised its safety.”
Sources:
Enrico Fermi Nuclear Generating Station wikipedia entry
We Almost Lost Detroit, a 1975 Reader’s Digest book by John G. Fuller, presents a history of Fermi 1, America’s first commercial breeder reactor, with emphasis on the 1966 partial nuclear meltdown.
Michael Hiltzik, “50 years after ‘we almost lost Detroit,’ America’s nuclear power industry faces even graver doubts“, Los Angeles Times, October 3, 2016.