In November of 1951, a small group of engineers gathered at a private astronomical observatory on the shore of Lake Angelus, in Oakland County, Michigan. They had spent the previous year visiting nearly every nuclear facility in America that they could get into with an Atomic Energy Commission clearance — Argonne, Hanford, Oak Ridge — reading classified reports, interviewing physicists, doing the kind of patient, systematic technical survey that only engineers with genuine access and genuine purpose ever bother to do. Then they sat down to rank what they had found.

Their first choice — the reactor type they believed, after all of that study, represented the best long-term approach to nuclear power — was a high-temperature thorium breeder using a mobile, fluid fuel with continuous reprocessing.

Read that again. In 1951, a team of industrial engineers, working from an engineer’s perspective rather than a physicist’s, independently arrived at the same conclusion that Alvin Weinberg would spend the next two decades building and proving at Oak Ridge. They had looked at the whole landscape of nuclear power and pointed straight at the fluid-fueled thorium reactor.

Then they built something else.

The story of why is the story of Walker Cisler, of the Enrico Fermi Atomic Power Plant, and of the forces that bent the first nuclear age out of shape. I think it needs to be told, and told plainly, because we are still wrestling with those same forces today. I have spent twenty years on this blog arguing that the thorium molten-salt reactor was set aside for reasons that had nothing to do with whether it would work. The Cisler story is the cleanest proof I know of that I’m right about that.

The industrialist

Walker Lee Cisler is not a famous name today, and that is its own small injustice. He was born in 1897 in Marietta, Ohio, grew up on a farm near Philadelphia after his parents divorced, and worked his way to Cornell on a mechanical engineering scholarship — partly funded, the story goes, by his mother selling twenty oak trees off the family property for $250. He graduated in 1922, spent two decades rising through the ranks at Public Service of New Jersey, and arrived at Detroit Edison in 1943 as chief engineer of power plants.

The timing sent him almost immediately to Europe. During the war, Cisler was the man who organized power infrastructure for the Allied Military Government. He walked ahead of jeeps through fog with a flashlight to seize German power plants before they could be destroyed. He crossed into Switzerland in uniform to negotiate redirecting electrical output from German systems to French ones. He entered Berlin with General Lucius Clay through streets where, as he later wrote, there were “dead and decaying bodies everywhere.” He organized the first postwar energy conference in that ruined city, scrounged Spam and bourbon from somewhere, and watched Russian engineers sing until half past two in the morning.

What the war gave Cisler, beyond technical skill and executive nerve, was a bone-deep understanding of what energy means to a civilization. He had seen the alternative. He had stood in cities without power, walked past silent factories, watched people go cold in the rubble of what had been industrial Europe. Out of that he drew a conviction that animated the rest of his career, and it is one I share without reservation: energy is not a commodity. It is the material precondition of everything else we call civilization, and the obligation to develop it abundantly and reliably is a moral obligation, not merely a commercial one.

He became president of Detroit Edison in 1951. By then he had already served as an AEC consultant, watched the civilian nuclear program take its first tentative steps, and concluded that private industry had a duty to be at the table when the decisions about nuclear technology were made. If industry wasn’t there, the technology would be shaped entirely by military requirements. And military requirements, as he was already beginning to see, led to very different choices than the requirements of civilian power.

The Lake Angelus meeting

In October of 1950, Cisler and his associates at Detroit Edison began a joint study with the Dow Chemical Company on the feasibility of civilian nuclear power. The AEC authorized them to review classified reactor data and make recommendations, and for the next year the Dow–Detroit Edison study group did exactly that: a thorough, clearance-level review of every reactor concept then under development in the United States.

By October of 1951 they had ranked three approaches in order of preference.

First was a high-temperature thermal breeder running on uranium-233 — the fuel bred from thorium — circulating its fuel as a liquid and continuously reprocessing it to pull out fission products.

Second was a modified heavy-water reactor.

Third was the fast plutonium breeder, built on the foundation of Experimental Breeder Reactor-I, then operating out in Idaho.

On November 8, 1951, the informal technical committee met at the McMath-Hulbert Solar Observatory on Lake Angelus — the private facility of Robert McMath, a solar astronomer who also sat on the Detroit Edison board — and drafted a statement. It read, in part:

It is our belief that a high temperature breeder using a mobile fuel with fluid reprocessing represents the best approach. This is based on a careful analysis of the problem including our observations at AEC installations and elsewhere.

A mobile fuel with fluid reprocessing. In 1951, that is Cisler’s engineers describing, in their own words, what Weinberg was already reaching toward at Oak Ridge: a reactor in which the nuclear fuel is dissolved in a liquid that circulates through the core, with fission products removed in real time and none of the fuel-element failures that plague solid-fuel designs. The men who had toured every major nuclear installation in the country looked at the full menu of options and pointed at the fluid-fueled breeder.

And here is the part I find most striking. They didn’t get there through reactor physics. They got there through engineering systems analysis — by asking which approach, taken as a whole integrated system, gave the best combination of fuel economy, safety, and long-term sustainability. Weinberg the physicist and Cisler’s engineers came at the problem from opposite directions and met in the same place. When that happens, it is usually because the answer is correct.

Why they built something else

The study group’s first preference was set aside. Their third choice was built. The reasons are worth understanding, because they are not the reasons you would guess.

Part of it was honest engineering. The thorium/U-233 fluid-fuel approach demanded materials and heat-transfer technology that simply didn’t exist at engineering scale in 1951. The fast sodium-cooled plutonium breeder had EBR-I to build on. The path to building it was clearer, even though the engineering itself was harder and, as things turned out, meaner.

But the deeper reason was structural, and it had nothing to do with merit. The fast breeder produced plutonium, and the government needed plutonium — needed it desperately. In April of 1947, when AEC Chairman David Lilienthal went to the White House to brief President Truman on the nuclear stockpile, he delivered what was then perhaps the biggest secret in America: there were essentially no operable atomic bombs in the vault. The arsenal that Churchill believed was restraining Soviet aggression barely existed. For years afterward, the emergency production of fissile material was the overwhelming priority of the early AEC, and that priority ran downstream through every budget line and every technology decision the agency made.

The thorium cycle, for all its elegance, produced uranium-233. And U-233, gloriously, is not well suited to weapons — the U-232 that comes with it sees to that. If you wanted the government to fund your reactor in those years, it helped enormously to make something the government wanted. The fast breeder made it. The fluid-fuel thorium breeder did not.

Cisler understood this perfectly well. The study group’s own documents recorded that the final selection of the fast breeder was “made largely on the basis of the reactor’s ability to produce plutonium fuel as well as power and the value of plutonium to the government.” Let that sentence sit for a moment. The best long-term reactor was passed over not because it was technically inferior but because it wasn’t militarily useful. The same logic, almost word for word, is the one I have spent two decades documenting at Oak Ridge. It bent the whole field.

The Enrico Fermi Atomic Power Plant

On March 30, 1955, Cisler filed a proposal with the AEC on behalf of a consortium of utilities, architect-engineers, and manufacturers organized as the Power Reactor Development Company, the PRDC. The plan was to design, build, own, and operate a 100-megawatt fast-neutron breeder reactor at Lagoona Beach, Michigan, on the shore of Lake Erie just south of Detroit.

They named it the Enrico Fermi Atomic Power Plant, after the physicist who had achieved the first controlled chain reaction in Chicago in 1942, and who, Cisler noted, had “indicated his belief in the critical importance of the breeder reactor development.”

What followed was twenty years of extraordinary effort, extraordinary expense, and, in the end, heartbreak.

The financial structure rested on a single assumption: that the federal government would pay somewhere between $45 and $100 per gram for the high-grade plutonium the breeder would produce. In 1954, when the project was being planned, the estimate ran as high as $100 per gram. In 1956, the AEC quietly told PRDC the price would be $45 — classified information at the time. In 1957, when the schedule was declassified, PRDC discovered the real number was $30. By 1964, the government had abandoned the price-support program altogether, because by then the weapons program that had justified the breeder in the first place had produced so much plutonium that the government no longer wanted to buy any more of it.

$100, then $45, then $30, then $9.50 in the 1962 AEC report to President Kennedy, then nothing. That sequence is one of the more consequential bait-and-switches in the history of American technology policy. The entire commercial case for Fermi-1 was built on plutonium revenues that were systematically withdrawn while the plant was still being poured in concrete.

The engineering fought back, too. There were three major mechanical failures during non-nuclear testing. There were legal battles that tied the project in knots for years: the construction permit granted in 1956 was challenged by labor unions, overturned by the Court of Appeals in 1960, and finally upheld by the Supreme Court, seven to two, in June of 1961 — five years after ground was broken. And then, just when the reactor reached a million kilowatt-hours of production in August of 1966, with Cisler telegraphing his board that fifty-three consecutive hours at half power was a “historic achievement,” it happened.

October 5, 1966

At five minutes past three on the afternoon of October 5, 1966, a reactor operator named Mike Wilber noticed something wrong. The control rods were nine inches out of the core instead of the expected six. Something was absorbing extra neutrons. Four minutes later, the radiation alarms sounded, and the Class I emergency announcement came over the plant intercom: “Now hear this. The containment building has been secured.”

The Monroe County Sheriff was called and asked, quietly, not to enter the incident in his log. Walter McCarthy, the plant’s chief engineer, was in a meeting in downtown Detroit and told his wife he wouldn’t be home for dinner. Cisler was in New York and couldn’t be reached. And the question of whether to evacuate the Detroit metropolitan area — four million people, no subway, freeways that clog on an ordinary Tuesday — was, briefly and seriously, on the table.

It took eleven months to find out what had gone wrong.

In September of 1967, engineers lowered a periscope forty feet into the reactor through a hole in the rotating shield plug: a quartz light and fifteen optical relay lenses, peering down into a vessel full of sodium. They found an object that one witness said looked “like a crushed beer can.” A retrieval tool was fashioned out of bicycle chains and threaded through a fourteen-inch coolant pipe. It took months of work, performed essentially blind, before the object was finally drawn out at ten past six on a Friday evening.

It was a triangular piece of zirconium, about the size of a large book. And here is the detail that deserves never to be forgotten: it had been installed as a safety measure.

An engineer named Al Amorosi had added six triangular zirconium plates to protect the conical flow guide at the bottom of the reactor, a modification made after the original design was finished. He had even written a memo observing that it would be “easier to implement than to have to justify not doing so.” The change was never recorded on the as-built blueprints. One of the plates worked loose, was swept along by the sodium, and lodged against the inlet of a fuel subassembly, choking off the coolant flow. The fuel melted. An unrecorded safety measure caused the accident it was meant to prevent. There is a lesson in that about complexity and about honesty in engineering records, and it is not a comfortable one.

The reactor was down for three and a half years. It was eventually repaired and brought back, reaching its full licensed power of 200 megawatts in October of 1970. Engineers from Japan, Germany, Belgium, the Netherlands, and elsewhere came to study it. It ran, and it produced data of real value to fast-breeder development around the world.

But it never sold commercial power in any meaningful quantity. By 1972 the money was gone. The gap between what the project needed to keep going — about $10 million — and what could be raised had become unbridgeable. In a year when the AEC was spending $200 million on the liquid-metal fast breeder program, $10 million could not be found to keep the only operating fast breeder in America alive.

The total cost of the Fermi project was $143 million. Total revenue from heat sales over its entire operating life: $126,154. The accident, incidentally, gave John Fuller the title of his 1975 book, We Almost Lost Detroit — which did more lasting damage to the public’s trust in nuclear power than the event itself ever warranted.

What Weinberg was building, five hundred miles away

While Fermi-1 was being built, litigated, melted, repaired, and finally abandoned, Alvin Weinberg was at Oak Ridge National Laboratory, five hundred miles to the south, building the other reactor. The one the Lake Angelus engineers had ranked first.

The Molten-Salt Reactor Experiment reached criticality in June of 1965 and ran, with the kind of stable, continuous operation that the solid-fuel sodium-cooled Fermi reactor could never quite manage, through 1969. In October of 1968 it began operating on uranium-233 — the fuel bred from thorium — the first reactor in history to do so. The fluid fuel, the continuous operation, the thorium cycle: all of it real, all of it demonstrated, none of it theoretical anymore.

Weinberg had proved the technology worked. The reactor that Cisler’s engineers had identified as their first preference in 1951 had been built and run. And then it was shut down — in December of 1969, not because it failed but because the program was being defunded.

The man pushing the other direction was Milton Shaw, director of the AEC’s Division of Reactor Development and Technology, who — at President Nixon’s direction — was pouring every available dollar into the liquid-metal fast breeder, the line that would eventually run through the Clinch River project and consume billions before its own cancellation in 1983. Shaw was cut from the Rickover cloth: singleness of purpose, and, as Weinberg put it in his memoir, woe unto any who stood in his way. The molten-salt reactor needed new materials, new chemistry, new manufacturing. It wasn’t what the establishment had decided to build. And Weinberg, who kept espousing it, and who kept raising uncomfortable questions about reactor safety besides, had become inconvenient.

So they got rid of him. Late in 1972, Weinberg was told he had to go. He had run Oak Ridge for eighteen years; he began a paid leave on the first day of 1973 and was officially gone by the end of it. “I had never been fired before,” he wrote. He went on to Washington for a miserable year running an energy-research office during the oil crisis, and later built the Institute for Energy Analysis back at Oak Ridge — but he never directed the laboratory again.

The program he left behind was killed not once but twice, and the sequence is worth stating exactly, because it tells you everything about how this technology died. In January of 1973, the AEC directed Oak Ridge to conclude all molten-salt reactor development work, for budgetary reasons. Then, in January of 1974, the program was reinstated — a full year spent reassembling staff and reactivating development facilities that had already been scattered to other programs. Through 1974 and 1975 the work was real and forward-moving: developing a modified Hastelloy-N that could resist the tellurium-induced cracking first seen in the MSRE surveillance specimens, and demonstrating that tritium could be managed in a 1000-megawatt molten-salt breeder. And then, in February of 1976, ERDA — the AEC’s successor — directed Oak Ridge to terminate the program a second time, again for budgetary reasons. This time it stayed dead. The staff and the facilities were reassigned, the reports were closed out, and the only reactor lineage an independent group of engineers had ranked first in 1951 was abandoned in the United States for the next several decades.

The parallel endings

The two stories ended within a year of one another, and the symmetry is almost too neat to be borne.

The PRDC’s executive committee voted to decommission Fermi-1 on November 27, 1972. Within weeks, at the turn of 1973, Oak Ridge was directed to wind down the molten-salt program for the first time, and Weinberg — already told he was finished — began the leave that would end his eighteen years running the laboratory. The two stories crested together: one program written off after twenty years and $143 million, the other set aside after years of quiet, successful operation. And while the molten-salt reactor would flicker back to life for a single budget cycle before being extinguished for good in 1976, Fermi-1 never returned at all.

One was the third choice of a group of engineers who knew the field better than almost anyone alive. The other was the technology those same engineers had named their first choice. Neither would be touched again for decades.

What the story teaches

There are a few things I take from the Cisler story, as someone working today on what he and Weinberg were working toward then.

The technical judgment was sound from the very start. The Lake Angelus engineers were not wrong. Their first preference — fluid fuel, thorium cycle, continuous reprocessing — has held up across seventy years of subsequent analysis as genuinely superior in the ways they identified. The MSRE proved it ran. The physics has only gotten clearer. They surveyed the field in 1951 and pointed at the molten-salt approach, and they were right, and they were right for the right reasons.

The path dependency was real and durable. The choice in 1951 to build the fast sodium breeder instead of the fluid-fuel thorium breeder created a technology path that proved nearly impossible to leave. Every dollar spent on liquid-metal infrastructure made the molten-salt path look more expensive by comparison. Every engineer trained in sodium technology was an engineer not trained in fluoride chemistry. The institutional weight of the wrong choice compounded, year over year, decade over decade.

The weapons program was the hidden hand. The original reason the thorium cycle was deprioritized — that it didn’t make weapons-grade plutonium — was almost never stated plainly in public, but it ran through every resource decision underneath. And here is the bitter irony: once the weapons program had produced so much plutonium that the government stopped buying it, the rationale evaporated. The requirement that had bent civilian nuclear development clean out of true was gone. But the bend remained. It remains today. I would argue we are still living inside it.

And private industry was willing to take real risks. The thing that strikes me most about the Fermi-1 story is how much Cisler’s consortium was genuinely prepared to lose. Detroit Edison put up $30.6 million of a $143 million project. The utilities guaranteed bank loans out of their own assets. They kept writing checks through accident, litigation, and overrun, year after year, because they believed in what they were building. That appetite for risk is not something to take for granted. It existed. It was real. And it was exhausted, in the end, by a project built on financial promises that the government quietly withdrew. I think about that often when people tell me the private sector won’t build advanced reactors. It will. It did. We should be careful about how we treat it when it does.

A last note

Cisler lived until 1994, dying at ninety-six. In his autobiography, written in 1976, he looked back on the Fermi project with characteristic restraint: “This is a major disappointment to me.”

He had spent his career trying to bring nuclear energy into civilian life. He had identified the right technology before almost anyone, built the wrong one because the political and economic conditions demanded it, watched that wrong one fail in ways that damaged the credibility of nuclear power for a generation, and watched the right one cancelled at Oak Ridge at almost exactly the moment his own plant was being shut down in Michigan. The technology his engineers had named superior in 1951 was proven to work in 1969. Two years later it was cancelled. Two years after that, his own plant was decommissioned. The irony was complete, and he had to live inside it for another twenty years.

What Cisler couldn’t know in 1994, and what we know now, is that the technology his Lake Angelus engineers pointed at is still pointing back at us. The molten-salt reactor, the thorium cycle, the fluid-fuel approach — after seventy years they remain exactly what they were in 1951: the most promising long-term path to nuclear energy that is genuinely abundant, genuinely safe, and genuinely sustainable. The physics hasn’t changed. The engineering has been proven. What never existed, until very recently, was the political and economic room to build it.

That room may finally be opening. After two decades of writing this blog, I don’t say that lightly, and I have learned not to promise it. But Walker Cisler was right, and Alvin Weinberg was right. They were right in 1951, and right in 1969, and they are right now. The only question left is whether we are finally willing to act on what they knew.

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The history of the Enrico Fermi Atomic Power Plant is documented in Fermi-1: New Age for Nuclear Power (American Nuclear Society, 1979). Cisler’s own account appears in his autobiography A Measurable Difference (1976). John Fuller’s We Almost Lost Detroit (1975) gives the most detailed account of the 1966 accident and its investigation.