SIX

THE END OF NUCLEAR POWER

In February 2011, I went to Oak Ridge to view Alvin Weinberg’s papers. It had been a wet winter, and rainstorms lashed the hills surrounding the town. Oak Ridge today has become something of a bedroom community for Knoxville, 24 miles east on I–40; new condos litter the ridgelines, and the town itself has some trappings of a twenty-first-century American town: a health club, a Wal-Mart, a few chain restaurants strung along the Oak Ridge Turnpike. Weinberg would still recognize the place, but it would not be easy for a newcomer to perceive that one of the country’s most sophisticated physics and chemistry labs sits just outside the city limits.

Some of Weinberg’s papers now reside at the Howard Baker Center at the University of Tennessee in Knoxville. But the bulk is housed in a storage room the size of a walk-in closet at the Oak Ridge Children’s Museum, a small schoolhouse-sized facility on West Outer Drive, up the hill from the center of town. No one could really explain to me how they ended up there; I’d been directed to the museum by Weinberg’s son Richard, a retired biochemist. The staff welcomed me warmly, but they were slightly bemused. It was obvious that no one had asked to see Weinberg’s archive in years. Oak Ridge National Laboratory honors its past, but it has not done a great job of preserving the records of its longest-serving director. This neglect, I thought, epitomized the neglected legacy of the man. Weinberg is a major figure in the history of nuclear power in this country, but, unlike Hyman Rickover or Edward Teller or even David Lilienthal, Weinberg’s name is virtually forgotten today.

The papers are stored in metal filing cabinets and cardboard boxes, piled literally to the ceiling of the windowless room. There’s an index of sorts, and the cabinets are numbered, with subject-heading tabs on the file folders inside. Most papers are duplicates of Weinberg’s correspondence, typed out on thin translucent ORNL letterhead paper, along with articles from scientific journals and technical reports from various laboratory programs, including the molten salt reactor (MSR). I spent an afternoon there, reading letters to editors, policy makers, Atomic Energy Commission (AEC) officials, and other scientists, many of them more than four decades old. I was hoping for a revelation, I’ll admit, a smoking gun that would reveal some treachery at the birth of the nuclear power industry. I didn’t find it exactly; most of the archive is routine administrative stuff. But buried in those cabinets is the inside story of a fierce bureaucratic struggle about the future of the MSR Experiment—and in a wider sense about the future of nuclear power. It was melancholy reading.

“Finally, I should like to take this opportunity to make known to you once again my objections to the drastic reduction in fluid fuels [funding] planned for fiscal year 1960,” Weinberg wrote to Willard Libby, the AEC commissioner, in January 1959. “ . . . To me it seems imprudent to cut fluid fuels in about half . . . instead of cutting back a little on several other much larger enterprises.”¹

That was almost a yearly lament. Weinberg spent most of the late 1950s and the 1960s pleading, arguing, and cajoling for more support for the fluid-fuels program and, once the aqueous homogeneous reactor project was canceled, specifically for MSRs. In 1956 ORNL’s budget peaked at $60 million, with more than 4,300 people on staff. “We are the largest nuclear energy laboratory in the United States,” Weinberg boasted, “and we are among the half-dozen largest technical institutions in the world.” ²

His exultation proved premature. The cancelation of the ill-conceived aircraft reactor in September 1957 resulted in a 20 percent across-the-board budget cut for the ORNL. Staffing was cut by 10 percent. The Eisenhower administration froze the laboratory’s budget in 1957, forcing Weinberg to put off a major expansion that would have added a half-million square feet of new work space. These “cataclysmic setbacks” emphasized the new reality: in the militarized, scientific culture of the Cold War, Oak Ridge was fighting for its survival.³

Weinberg believed that thorium-based fluid-fuel reactors would ensure the lab’s central place in the emerging nuclear power industry. He was wrong. Officially the MSR Experiment lasted from 1959 to 1973, when it was canceled, only to be reinstated for reasons lost in the obscurity of long-ago energy policy in 1974 and then finally terminated for good in 1976. The most remarkable thing about the program is that, by all technical and economic measures, it was a resounding success. Politically, though, it was a dud. And year by year, letter by letter, Alvin Weinberg waged a lonely, ultimately losing battle to keep it alive.

Weinberg would say later that his lukewarm support for nuclear aircraft helped doom his quest to keep the MSR alive. In 1959 Weinberg was appointed to the White House Scientific Advisory Committee; his words had come to carry a weight they lacked when he was merely the director of Oak Ridge, however prestigious that institution was. In conversations that year with Herbert York, the former director of Livermore National Lab who had become the director of defense research and engineering at the Pentagon, Weinberg shared his skepticism. A year later John Kennedy shut down the Aircraft Nuclear Propulsion (ANP) program. “I don’t have the slightest idea whether my conversation with Herb York had anything to do with the cancellation,” Weinberg later recalled. “But Don Keirn, AEC’s manager of ANP, and Kenneth Davis, who was the director of reactor development for AEC, must have thought so.”⁴

After the cancelation, Keirn and Davis cornered Weinberg at the Roger Smith Hotel in Washington and accused him of treachery and disloyalty. “They chewed me out for about an hour,” Weinberg recalled.⁵ Permanently labeled an outsider and a malcontent, he would struggle with the AEC for the rest of his career at Oak Ridge. As laid out in his official correspondence, those struggles seem quixotic now. Weinberg was trying to change an entrenched militaristic culture with science and reason. Such battles seldom lead to victory. Nevertheless, he took up the search for sustainable nuclear power, based on molten salt thorium breeders, with a purity of purpose that no one else in the industry or the scientific community could match. In 1958 he had published an essay entitled “Power Breeding as a National Objective.” In it he argued that “current economics alone should not be the sole basis for choosing which reactor system to pursue. Efficient use of the raw materials of nuclear energy—uranium and thorium—was equally important.”⁶ Eventually they would become more important. Using the criterion of efficiency, there was no question which raw material made more sense. It was thorium, burned in molten salt reactors.

Weinberg’s fervor for liquid-fuel reactors, and for the boundless potential for nuclear power in general, would lead him into some flawed projections. Indeed, he was ridiculed by early environmentalists. His memoirs take on an elegiac, even apologetic, tone as he looks back on the “nuclear euphoria” of the 1960s. He never stopped believing, though, that thorium-based nuclear power in fluid-fuel reactors could, in the long run, slake humanity’s energy thirst for the foreseeable future.

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IN 1958, AS PART OF HIS LONG twilight struggle to keep the fluid-fuel reactor program alive, Weinberg invited Eugene Wigner to visit Oak Ridge to review the state of the science. The second aqueous homogeneous reactor experiment had reached apparent failure when a hole formed in the interior wall of the core, made of a corrosion-resistant zirconium alloy. Jury-rigging a kind of periscope-and-mirror contraption, the engineers discovered that a region of the tank wall had melted when uranium settled out of the fuel solution and collected in that one spot. Stability of the fluid fuel had, from the earliest days of the concept, been a known hazard. Now it seemed that fuel instability might halt the fluid-fuel program in its tracks.

Wigner had returned to his post at Princeton; inviting him to Oak Ridge was a political risk on Weinberg’s part. The former Oak Ridge research director was closely associated not only with his protégé Weinberg but with the fluid-fuel thorium breeder concept he’d originated before the war’s end. Wigner’s return was inevitably seen by some in Washington as an end-run around the AEC to lend to Weinberg’s pet project the weight of Wigner’s support. And, to some degree, they were right: Wigner, who spent December 22 and 23 in Oak Ridge touring the facility and being briefed on the fluid-fuel reactor program, came away convinced that the obstacles could be overcome. In the new year he wrote a long letter to Libby outlining his views. The letter refers specifically to aqueous homogeneous reactors, but its conclusions are applicable to all thorium-based fluid-fuel reactors. The letter is worth reviewing in detail for its candid look at the advantages and the challenges of thorium-fueled molten salt reactors. Much of Wigner’s analysis remains relevant to today’s LFTRs.

Wigner examined first the technical hurdles to fluid-fuel breeders and then the economics. Under “Technical Problems” he listed five elements of the technology: breeding, the blanket, the core, containment, and personnel. The last, Wigner argued, was a question of identifying and assigning the right talent. In the postwar years Oak Ridge had lost many of its brightest minds to academia and, in some cases, to industry. “It is my impression that the problems need the interest of some of the deeper thinkers in the laboratory.”⁷

This was not an unprecedented observation from Wigner. A decade earlier, looking at the early postwar attempts to fashion a nuclear power reactor, he commented that reactor development had suffered from a lack of attention from “first-rate scientists.” Now he was calling on the AEC to devote its best scientists to the development of new and advanced reactor designs. Since most of the Oak Ridge scientists had trained under Wigner and Weinberg, this was an understandable conclusion.

The design of the core received the most attention from Wigner. Fueled by a solution containing ten grams of enriched uranium per kilogram of heavy water, which circulated through its core at the rate of 400 gallons (1,450 liters) per minute, the reactor’s fuel loop was comprised of the central core, a pressurizer, a separator, a steam generator, a circulating pump, and much interconnected piping. The core vessel was about a meter in diameter, centered inside a spherical pressure vessel made of stainless steel. A reflector blanket of heavy water—which in future molten salt designs would contain a thorium fluoride solution to breed U-233—filled the space between the two vessels. It was, according to the official history of ORNL, “perhaps the most exotic nuclear reactor ever built.”

The challenge, as Wigner saw it, was to design a core in which the fluid (whether molten salt or aqueous) could achieve a high-enough temperature without losing stability—that is, without separating into two phases, one of them a uranium concentrate capable of melting the core wall. Unfortunately, this uranium-rich phase tended to separate and form a solid layer on the inner wall of the vessel. There were two ways to avoid phase separation: a design that involved “violent mixing and turbulence” in the core and a streamlined version that limited turbulence as the chain reaction occurred and the fluid flowed with a slow but more or less uniform velocity through the core. Wigner intuitively favored that streamlined system but acknowledged that “the weight of evidence at present” seemed to argue for high turbulence. In a broader sense, he said, the experimental design was simply not in accordance with the requirements of a thermal breeder. (In particular, the phase separation seemed to happen at screens that had been inserted into the core to help control the flow, when a layer of “rich phase” material adhered to the screens).⁸

“I am fully convinced that the problems of the core will be solved,” Wigner wrote. “The reason that they have not yet been solved is principally due to two circumstances.” First, the designers did not understand the phase diagram of the fluid in the core; second, “they followed their first impulses in design too strongly.”

Wigner believed that adjusting the flow of fluid through the core would provide the velocity needed to prevent the uranium from settling on the walls, and he proposed removing the screens. He also proposed switching the inlet and outlet valves to reverse the fluid flow through the reactor. These measures would prove to be successful. And Wigner, who would win the Nobel Prize five years later, declared his unconditional support for Weinberg’s efforts.

“It is my opinion that abandoning the program would be a monumental mistake,” Wigner warned Libby.⁹

Reluctantly, Libby and the other AEC commissioners concurred. After several extended test runs using the new configuration, the reactor operated continuously in 1959 for 105 days—at the time a record for uninterrupted operation of a nuclear reactor. Wigner’s intervention almost certainly saved fluid-fuel reactors—or, at least, postponed the day of their demise. The experiment conclusively demonstrated that such machines could generate power using far simpler systems than pressurized light-water reactors, with new fuel added and fission products removed continuously while the reactor continued to operate. Despite these accomplishments, near the end of that year another hole appeared on the core wall, and Westinghouse abandoned its plan to build a homogeneous reactor as a central power station for the Pennsylvania Power and Light Company. The AEC, as I’ve discussed, decided to place its fluid-fuel bets on the MSR, which would breed U-233 from thorium. As the 1960s dawned, Weinberg was confident this would happen.

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NOT THAT HE WAS BLIND TO THE COMPETITION. “The boiler [i.e., pressurized-water system] bandwagon has developed so much pressure that everyone has climbed on it, pell mell,” Weinberg complained in a letter to Wigner.¹⁰

By this time, 14 years into its existence, the AEC had become more of an arm of the Pentagon, and a distributor of funding to the competing national labs’ reactor programs, than a true promoter and binding force for the development of peaceful atomic power. To be sure, the economic arguments for nuclear power from the dominant light-water reactor designs were weak: Commonwealth Edison had calculated in the mid-1950s that coal-fired plants would cost about $77 per kilowatt to build. Nuclear plants would cost $277. Following the “Atoms for Peace” speech, the Eisenhower administration pursued a two-pronged strategy whose inner contradictions would haunt U.S. foreign policy for decades: enabling the spread of nuclear technology, mostly through light-water reactors, while continuing a massive buildup of the nuclear weapons stockpile, including the “Super,” the hydrogen bomb first tested during the Truman administration in 1952. Light-water reactors, by their nature, required the enrichment of natural uranium. Pursued to its logical end, the enrichment of uranium was the first, and in many ways the most difficult, step toward obtaining nuclear weapons. Among the countries that benefited from U.S. atomic technology proliferation were India and, eventually, China.

The development of a strong nuclear industry, said a National Security Council memo, “is a prerequisite to maintaining [America’s] lead in the atomic field.”¹¹

Established by the scientists of the Manhattan Project, that lead proved to be short lived.

By the end of the decade Rickover’s light-water reactors had suffered no serious accidents. The nuclear sub program had done more than anything else to demonstrate the ability of nuclear plants to provide safe and continuous power under demanding conditions. Many scientists, though, remained concerned about the safety of nuclear plants, and the congressional Joint Committee on Atomic Energy had commissioned a probability study (the first of many) to establish the level of risk. Published in early 1957, the report was sobering: While the chances of a serious accident were considered remote, a worst-case scenario could result in 3,400 deaths, 43,000 injuries, and $7 billion in property damage.¹² Like all such studies, it was shelved after generating a few scary headlines. And, officially, support for nuclear power continued unabated.

Unfortunately, this political enthusiasm failed at first to translate into commercial activity. By the end of the 1950s the United States, the nation that had harnessed nuclear fission and invented the first nuclear reactor, the adopted home of Fermi and Wigner and Teller and Szilard, was actually behind other nations in the development of power-generating reactors. In 1954, with Washington gripped by the Army-McCarthy hearings, the first civilian nuclear power plant, a five-megawatt plant south of Moscow, was started up by the Soviets. The British, whom the United States had essentially tossed out of the nuclear effort after Hiroshima, had built a 100-megawatt plant at Calder Hall. Lewis Strauss, the AEC chair enthralled by Rickover, had predicted that future Americans would enjoy nuclear power “too cheap to meter.” But, hindered by an AEC primarily focused on the military applications of nuclear energy and by an industry still dependent on the Pentagon for both staffing and financial backing, nuclear power in the United States at the time of John F. Kennedy’s inauguration had failed to fulfill the promise foreseen by its early enthusiasts.

That situation would change, the AEC was convinced, with the emergence of breeder reactors. When the Soviets, at the first United Nations conference on Peaceful Uses of Atomic Energy in Geneva in 1955, announced plans for a breeder reactor that would generate power, Strauss immediately recruited the Great Lakes utility Detroit Edison to apply for an AEC license to build a commercial breeder. That project, on the shore of Lake Erie, would become the ill-fated Fermi 1 liquid metal breeder reactor. And the misguided efforts to build a safe, efficient breeder reactor would ultimately doom Weinberg’s thorium-based MSR.

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WHEN I FIRST STARTED RESEARCHING the history of thorium reactors, I received—and mostly swallowed—a straightforward tale: The United States abandoned thorium reactors because they didn’t produce plutonium for bombs. Full stop. Populated by pacifist scientists on the one hand and Machiavellian warmongers on the other, this made an appealingly symmetrical story. But it wasn’t the whole truth. In fact, I realized as I photocopied old letters that the truth, as it tends to be, was much more complicated. In the early 1950s molten salt thorium-fueled reactors lost out to light-water reactors because the latter were more developed and Rickover wanted to build nuclear subs as fast as the Navy would fund them. Later, in the 1960s, MSRs lost out to liquid-metal breeders for a constellation of reasons that included, but were not limited to, the Cold War demand for nuclear warheads. This was a harder weave to unravel and a harder story to tell.

Despite lukewarm support from the AEC, the Molten Salt Reactor Experiment (MSRE) proceeded in the new decade as Weinberg’s men gradually solved the materials and design issues that had plagued the aqueous homogeneous technology. Molten salts were more stable than aqueous solutions; they provided a clear path to U-233 breeding from thorium; and they had such a high boiling point (680 degrees Fahrenheit) that the reactor could operate at atmospheric pressure—a fundamental advantage over not only pressurized water reactors but also the aqueous homogeneous system. The “two-fluid” design of the MSR involved complicated plumbing to keep the fuel salt and the blanket salt separate but interlaced within the graphite core, but it remained a simpler machine than the pressurized water reactors (PWRs) of the day. First brought to criticality on June 1, 1965, the MSR experiment achieved a number of important milestones: it ran continuously for six months, it demonstrated the practicality of molten salts in a nuclear reactor, and, on October 2, 1968, it went critical with uranium-233, bred from thorium. Four months later it reached full power (8 megawatts) using U-233. To Weinberg, Mac MacPherson, and their team, it seemed an ideal system, the Platonic version of a nuclear reactor.

“Here we had a high-temperature fluid-fuel reactor that operated reliably and, even in the primitive embodiment represented by MSRE, had remarkably low fuel costs,” Weinberg wrote.¹³

In December 1969 the MSR was shut down to make way for what Weinberg believed would be more advanced molten salt designs and a full-fledged demonstration plant.

To be sure, there were technical difficulties. Various mechanical problems delayed start-up for a period in 1964–65. During the experiment three persistent challenges revealed themselves. One, the Hastelloy-N walls of the reactor vessel, subjected to constant neutron bombardment for a period of years, suffered “radiation hardening” related to the buildup of helium atoms. The materials scientists at Oak Ridge later developed new alloys containing fine carbide precipitates that would hold the helium and limit the hardening. Future designs would include a blanket of fertile thorium, which would help protect the vessel wall.

The second problem also had to do with Hastelloy N. The pipes for the MSR developed tiny cracks on their interior surfaces caused by the fission product tellurium. Adjusting the chemistry of the fuel salt (increasing the percentage of UF₃, as opposed to UF₄) eliminated the cracking.

Third was the buildup of tritium, also a product of the fission of uranium-235 and uranium-233. A radioactive isotope of hydrogen, tritium penetrates metals easily and could be vented to the atmosphere through the steam generators. MacPherson’s men spent months on the tritium problem. Ultimately they realized that the intermediate salt coolant would capture the tritium, which could then be removed during the reprocessing system that was in place to purify the system of other poisons, such as xenon.

All those problems proved to be solvable. The extended full-power run of the MSR experiment—87 percent of the time during 15 months of operation—was a feat of nuclear engineering in itself. “When measured against the yardstick of other reactors in a comparable stage of development, it is seen to be indeed remarkable,” wrote the Oak Ridge scientists Paul Haubenreich and Richard Engel in a 1970 account of the experiment in the journal Nuclear Applications & Technology.¹⁴

Nevertheless, the demo plant was never built. The reasons why remain cloaked in myth, speculation, and institutional amnesia. At the center of the controversial decision, though, was Milton Shaw.

If there’s a Machiavelli in this story, it is Shaw. A native of Knoxville, he studied mechanical engineering at the University of Tennessee before joining the Navy, too late for World War II. After postgraduate study at the Navy Propulsion School at Cornell, he was assigned to the Pacific theater, where he served as an engineering officer until the surrender of Japan. At some point he sought out Rickover, who recognized in Shaw a perfect subordinate: bright, almost as driven as his superior, and equally pugnacious. Rickover sent him to the School of Reactor Technology at Oak Ridge, where Shaw was an average student. For 11 years, through 1961, he reported directly to Rickover in the Naval Reactors Bureau, becoming known as the admiral’s chief henchman, Beria to Rickover’s Stalin. Shaw was the project leader for both the Nautilus and the Enterprise, the first nuclear aircraft carrier, launched in 1960.

A Rickover man to his core, Shaw inherited Rickover’s abrasive, autocratic leadership style and his intellectual inflexibility. In 1961 Shaw became the senior assistant to the Navy assistant secretary in charge of all research and development for the Navy and the Marines, and in 1964 he joined the AEC as director of reactor R&D. In that capacity he accomplished the most significant feat of his career, aside from naval nuclear propulsion: killing the molten salt reactor and eliminating all competition to the liquid metal fast breeder reactor as the next stage of advanced nuclear power development.

Shaw always viewed Oak Ridge with distaste, regarding it as a lab full of prima donna propeller-heads and possible pinkos. He was especially scornful of Alvin Weinberg. Shaw “was accused of using his authority to destroy the lab,” wrote Charles Barton Jr., son of one of the preeminent nuclear chemists at Oak Ridge. “I do not know if that was his intention, but he certainly succeeded in destroying the Reactor Chemistry Division.”¹⁵

Weinberg, naturally, was more diplomatic. Late in life, in an interview with two journalists associated with ORNL, Weinberg described the man who effectively ended his Oak Ridge career: “Milton Shaw had a singleness of purpose. In many ways I admired him, and in many ways he drove me nutty. He had a single-minded commitment to do what he was told to do, which was to get the Clinch River Breeder Reactor built.”¹⁶

Weinberg, who was never convinced that liquid metal fast breeders could operate safely (and who was proved correct), disagreed with the Clinch River plan. “I think the [Atomic Energy] Commission decided that my views were out of touch with the way the nuclear industry was actually going.”¹⁷

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THE 1960S WERE WEINBERGER’S HEYDAY, his period of irrational exuberance. In Europe, unlike his native country, he was feted as a hero and a pioneer. He got an early taste of the Continent’s enthusiasm for advanced nuclear technology when he was invited to speak at the national laboratories of France, Great Britain, Germany, Denmark, Sweden, Italy, and just about every other country in Western Europe. The countries that had given birth to the incomparable scientific minds who ignited the atomic revolution—minus Hungary, which was frozen in the shadow of the Iron Curtain—now wanted to taste the revolution’s freedoms. Eagerly feeding what he called “international euphoria,” Weinberg became the new industry’s leading scientific evangelist. “I found myself becoming a sort of unofficial nuclear ambassador, invited by many of the fledgling European nuclear groups to visit and tell them about reactor developments at Oak Ridge.” Scientists in Asia, particularly Japan— the only country ever to be the target of a nuclear attack, and a place where the power of nuclear fission is given unique respect—likewise wanted to hear about the U.S. program. Even the Kurchatov Nuclear Institute outside Moscow, named for the father of the Soviet nuclear weapons program, welcomed the nuclear ambassador. Igor Kurchatov himself (“the Soviet equivalent of Robert Oppenheimer, Ernest Lawrence, and Enrico Fermi all in one”) introduced Weinberg to an audience of eager note-taking communist nuclear engineers.¹⁸

Everywhere he went, Weinberg preached the gospel of thorium. “I extolled the promise if not the virtue of nuclear power, especially if it was based on the thorium-burning molten-salt breeder.”¹⁹

In Moscow, as in Tokyo and Berlin and London, Weinberg found kindred listeners. Europe had no oil, only expensive coal mines; its power was costly, and its fledgling nuclear programs were firmly under civilian control. Weinberg’s travels gave him an outsider’s perspective on the system in which he worked: a military-industrial complex driven primarily by bombs and nuclear propulsion. “Even the naval program, though carried out adequately by GE, Westinghouse, and Argonne, was very much in the grip of Rickover and his people.” The best scientists had retreated to the universities or found work designing ever-more infernal machines of destruction. Nuclear power got, if not the dregs, a large share of the second-raters. In Europe it was different. Visiting nuclear stations in the Old World, Weinberg remarked, “I am struck by the technical sophistication of the European nuclear-plant managers as compared to the American plant managers I have met.”²⁰

Encouraged by this seriousness and sophistication, Weinberg proceeded to make speeches that would sound overly optimistic, even absurd, two decades later. The future of humanity, he claimed, lay in “burning the rocks and burning the sea.” Building reactors that used the virtually limitless supply of thorium in Earth’s crust, he said, would be like burning the rocks. In future centuries, he predicted, we would “burn the sea” in fusion reactors run on the deuterium from seawater—controlled versions of the thermonuclear bomb.

Fed by the dream of inexhaustible, inexpensive energy, Weinberg’s projections became grandiose. The Oak Ridge scientists studied the “construction of giant agro-industrial complexes built around nuclear reactors . . . as a means of providing food and jobs for millions of persons in underdeveloped countries,” the New York Times reported in 1968. A complex built around thorium breeders could sustain 100,000 farmers and laborers, “feed five million others and export fertilizers to grow food for 50 million additional people.” A 2,000 megawatt nuclear plant would desalt a billion gallons of water a day, irrigating vast plantations in the desert. Nuclear cities, enthused Weinberg, “could be the Apollo project of the nineteen-seventies.”²¹

The response of men like Rickover and Shaw to such fantasies is not hard to imagine. President John Kennedy, though, was swept away by Weinberg’s imagined nucleoparadise. In a speech just weeks before his assassination, JFK foresaw the day when vast nuclear stations would generate abundant electricity as well as a bottomless supply of freshwater: “We will have before this decade is out or sooner a tremendous nuclear reactor which makes electricity and at the same time gets fresh water from salt water at a competitive price.”²²

Weinberg even believed that thorium breeders would unravel the knot of Middle Eastern politics. With the encouragement of Howard Baker, the Republican senator from Tennessee, Oak Ridge produced a multivolume plan for nuclear agroindustrial complexes to be built at Al-Hammam, near Alexandria; in Israel’s western Negev desert; and an “international project” in the Gaza Strip. Technology would unite Arab and Israeli in a nuclear utopia. Israeli ambassador Yitzhak Rabin heard Weinberg out during a stopover at the Knoxville airport and, with Levantine skepticism, congratulated him for his chutzpah.

Others were also incredulous. By the late 1960s the publication of Peter Matthieson’s Wildlife in America (1959) and Rachel Carson’s Silent Spring (1962) had given rise to an environmental movement that increasingly decried nuclear power as an unacceptably risky energy source. Even some nuclear scientists, such as MIT’s Henry Kendall, a future Nobel laureate in physics and the founder of the Union of Concerned Scientists, had begun to turn against the atom as a source of electricity. After a 1970 speech in Vienna marking the twenty-fifth anniversary of the International Atomic Energy Agency—an occasion when Weinberg extolled the potential for limitless nuclear power and once again declared that “a visionary world of abundance” lay before us—he heard muttering in the corridors. Some audience members, many of whom were actually building nuclear plants and finding them far more expensive than the best-case cost scenarios laid out by Weinberg, called him a charlatan and accused him of indulging in “gross over-optimism.”²³ The tide was turning against him, but Weinberg, naively convinced that the thorium breeder would sweep away all possible objections, had not sensed it.

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DESPITE THE SUCCESS OF THE MSR EXPERIMENT, Milton Shaw issued a series of critical assessments of the technology culminating in a 1972 report designated WASH–1222. Titled “An Evaluation of the Molten Salt Breeder Reactor,” this document has taken on, in the thorium movement, a significance akin to the contemporaneous Pentagon Papers among antiwar activists during the Vietnam War. In a remarkable piece of bureaucratic jiujitsu, Shaw in WASH–1222 candidly acknowledges the thorium-based MSR’s obvious benefits and then summarily concludes that it should be abandoned. In classical rhetorical terms, Shaw’s argument is a syllogism: he takes two premises and from them infers a conclusion. But his logic is flawed. His first premise is that “it has not been proven that molten-salt reactors can work at commercial scales.” His second premise states, “Bringing the molten-salt breeder to commercial production would require large amounts of time and money, and the solution of daunting technological problems.”²⁴ The conclusion that the thorium breeder should be terminated does not follow. It was the first of many versions of what would become a familiar argument: It hasn’t been done before, and doing it would be challenging. So we shouldn’t try it at all.

“It is noted that this concept has several unique and desirable features; at the same time, it is characterized by both complex technological and practical engineering problems which are specific to fluid-fueled reactors and for which solutions have not been developed.” Those problems were “different in kind and magnitude from those commonly associated with solid fuel breeder reactors.”²⁵ Shaw estimated that $150 million had been spent to that point on the molten salt breeder reactor (MSBR) program, a figure that was almost certainly inflated. Total government investment to bring the molten salt breeder to commercial production would rise to about $2 billion, he said. (ORNL’s own proposal for future development of the molten salt breeder reactor, submitted in 1972, called for about $3.8 billion over 11 years.)

Of course, at that point the AEC was already engaged in developing a reactor that presented “problems different in kind and in magnitude” from conventional light-water reactors and that would consume far more than $2 billion during the ensuing decade. That technology was the liquid metal fast breeder reactor (LMFBR), embodied in the Clinch River Breeder Reactor program, on which the United States would eventually spend $8 billion without a single spade turned for construction. All the evidence today indicates that Shaw seriously overestimated the maturity of competing technologies (indeed, problems with the LWR itself would cost operators tens of billions of dollars in the next decade), and he vastly overestimated the challenges for the molten salt breeder.

Nonetheless, the Nixon administration had been sold on liquid metal breeders. In 1971, in the first-ever special presidential message to Congress on energy, Richard Nixon declared that “our best hope today for meeting the nation’s growing demand for economical clean energy lies with the fast breeder reactor.” Nixon requested an additional $27 million for fiscal year 1972 for the LMFBR effort and committed to a full demonstration of the liquid metal fast breeder reactor by 1980.²⁶

Shaw also notes that further development of the thorium MSR would require significant resources, particularly “qualified engineering and technical management personnel and proof-test facilities” that were in acute shortage at the time. This was nonsense; Shaw was deciding among competing technologies by stating the obvious fact that not all warranted the same level of government and industry commitment. He had already, since joining the AEC in 1964, worked tirelessly to whittle away the financial and personnel resources available to Weinberg’s MSR program—indeed, to throttle the R&D capabilities of Oak Ridge as a whole. Shaw had settled the matter in his own mind; liquid metal breeders would go forward, and molten salt breeders would wither. WASH–1022 was a whitewash that provided flimsy justification for a conclusion that had been reached years before.

In arriving at that conclusion, Shaw dismissed the level of private-industry interest in the MSBR as negligible. This was demonstrably false. The 1970 Minerals Yearbook, published by the Bureau of Mines, reported that “there was . . . a significant increase in private efforts involving this concept. The Molten Salt Breeder Reactor Associates, an association of five electric utility companies and a consulting engineering firm, completed Phase I of their study of the MSBR. In addition, 15 utility companies and six major industrial companies formed the Molten Salt Group, which will jointly study MSBR technology, including the feasibility of thorium as a fuel.”²⁷

Shaw’s reasoning was perfectly circular: Private industry will not invest in the MSBR as a commercial venture without the support of the government. We, the government, won’t support it. Thus private industry won’t invest in it.

Shaw himself had destroyed the resources that were required to bring the molten salt breeder program to fruition. In WASH–1222 he simply made explicit a policy he had pursued since joining the AEC. Molten salt reactors and thorium power never recovered from the blow. The program was officially terminated in 1973 in a letter to Weinberg that echoed Shaw’s dubious logic: “Among the many outstanding achievements in the MSR research and development program, the highly successful performance of the Molten Salt Reactor Experiment will long endure as the most significant,” wrote R E. Hollingsworth, general manager of the Reactor Division of the AEC. “However, the additional commitments by the Government of the costs and other resources which would be required to demonstrate the potential of the concept for commercial applications would be very high.”²⁸

Congratulations: your program was an outstanding success. Now we’re shutting it down.

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I FOUND THE SURVIVING SCIENTISTS who worked on the MSRE at Oak Ridge surprisingly fatalistic, today, about the fate of their program. “There was nothing we could do about it,” Richard Engel told me in an interview. “The matter had been decided in Washington.” It was an unfortunate decision, but they had other work to do, and families to feed, and soon they were on to other programs. Wishing otherwise was irrational.

Four decades on, though, the current state of our power supply and Earth’s climate demand understanding: Why was the molten salt breeder—a technology with demonstrable benefits over competing technologies, which had been proven to work, which had the support of industry and was certainly more economical than its competitor, the liquid metal fast breeder, shut down? Shaw may have been rigid and blinkered, but he was no fool. What could have been done differently?

Mac MacPherson, whose career was more tightly aligned with the MSR program than even Weinberg’s, believed that tactical errors made early on by the Oak Ridge leadership led to the program’s demise. First, Weinberg had failed to drum up support for the technology at other labs and in Washington, D.C.: “Only in Oak Ridge . . . was the technology really understood and appreciated.” Outside ORNL, predictions for the ultimate potential of the molten salt breeder were considered outlandish. In fact, Weinberg and his men had made the mistake of proceeding too cautiously, MacPherson argued: The scientists leading the molten salt program chose to wait until the MSR experiment proved successful before expanding the program to a full-fledged demonstration plant; by the time that happened, the liquid metal breeder had already gained momentum, along with the support of Shaw and his political mentor, Representative Chet Holifield, Democrat of California, the powerful chair of the Joint Committee on Atomic Energy. In a politicized arena, prudence was the enemy of innovation. The liquid metal bandwagon was rolling along, and “it was asking too much of human nature to expect them to believe that a much less expensive program could be effective in developing a competing system.”²⁹

Weinberg acknowledged the political shortcomings of the MSBR program, but he added another, more technical reason. Liquid metal breeders were an extension of the extant, and successful, light-water reactors. Molten salt technology, though simpler, was new and strange. Milton Shaw, a man whose entire intellectual and managerial background was in the naval reactors effort, believed that LWRs were a proven, mature technology, that nuclear safety was a nonissue, and that liquid metal breeders were the logical—indeed, the only—next step. He was incapable of entertaining the idea that a completely different and, in his eyes, exotic technology—even one that had been conceived during the war at the dawn of the Atomic Age—could present surpassing technical and economic advantages over what he saw as a perfectly fine system that already enjoyed broad institutional support. His personal distaste for Weinberg, who emphasized the long-term costs and risks of nuclear power, and for the unruly boys at Oak Ridge, was a separate but intertwined issue.

In a 2010 article on molten salt reactors in Mechanical Engineering magazine, David LeBlanc—a physicist at Carleton University in Ontario and the founder of Ottawa Valley Research Associates, a start-up created to advance new MSR designs—mentions another, more sinister reason for the MSBR’s cancellation. “Finally, and more speculatively, is the theory that the MSR was killed because it didn’t produce plutonium, which was a military objective.”³⁰

The theory is now repudiated not only by more circumspect scientists like Jess Gehin, a senior program manager for reactor technology at Oak Ridge, but by many in the thorium movement. The evidence that Shaw and the AEC killed the MSBR specifically because it wasn’t an efficient producer of weapons-grade plutonium is thin. But that misses the point.

Light-water reactors and their younger cousin, the liquid metal breeder, won out because of technological intransigence rooted in the military origins of the U.S. nuclear program. The men who controlled nuclear power in this country had come, almost uniformly, out of Rickover’s nuclear Navy; they saw civilian nuclear power as, at most, an extension of the nuclear weapons program—a congenial side benefit, as it were, to an overwhelming strategic imperative. The progressive militarization of U.S. society and industry—cited most famously in President Eisenhower’s valedictory speech of 1961 in which he gave a gloomy, prescient forecast of the rise of the military-industrial complex, warning the nation against placing its trust in generals, admirals, and their civilian contractors—prevented the nuclearati from seriously considering a technology that had little to do with nuclear weapons and that, moreover, had been advanced by a laboratory director with suspected antiwar and environmentalist leanings. Claiming that the cancelation of the program was a direct result of the demand for nuclear weapons is an oversimplification; saying that the two had nothing to do with each other is naive.

Ultimately, the AEC mandarins concluded that the molten salt breeder reactor couldn’t be done because it had never been done. Coming so soon after the triumphant landing of an American manned spacecraft on the moon—an effort that at the time of John Kennedy’s 1961 address to Congress was far less advanced than the molten salt reactor (and of far more doubtful benefit to the nation, and to humanity)—this was a dispiriting conclusion.

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THE AFTERMATH WAS EVEN MORE SO. Each of the three main figures in this drama lost his job, against his will and in humiliating fashion.

Weinberg was the first to go. In fact, his position had been deteriorating for some time—not only because of his support for molten salt reactors but because of his focus on nuclear reactor safety. As far as back as the mid-1950s, George Parker of Oak Ridge was measuring the lingering radioactivity of irradiated, melted fuel elements. In the early 1960s Parker, under Weinberg’s direction, instituted a series of annual international conferences on reactor safety issues. Shortly after Shaw came to power at the SEC, the conferences were terminated. The journal Nuclear Safety, published by ORNL, became the primary vehicle for new studies on the subject. And Alvin Weinberg became known as the conscience of the nuclear power establishment—a role that hardly endeared him to Milt Shaw or Chet Holifield, who by this time held virtually unchallenged power over the AEC.

In his most famous statement, Weinberg pithily expressed the dilemma in which nuclear power advocates found themselves: “We nuclear people have made a Faustian bargain with society. On the one hand, we offer . . . an inexhaustible source of energy. But the price that we demand of society for this magical energy source is both a vigilance and a longevity of our social institutions that we are quite unaccustomed to.”³¹

Weinberg seems to have gotten the message late that he was on the losing side of the debate. In 1972, in a discussion with Holifield and ORNL deputy director Floyd Culler, Holifield blurted out, “Alvin, if you’re so concerned about the safety of reactors, then I think it may be time for you to leave nuclear energy.”³²

The final straw was when Weinberg committed the sin of confessing his doubts to the opposition. Angered by Holifield’s rebuke, Weinberg agreed to have dinner with Ralph Nader, whose sister Claire worked with Weinberg at Oak Ridge. Nader at that time was becoming one of the loudest voices against nuclear power, and Weinberg was frank with him. Weinberg insisted to Nader that the chances of a serious nuclear accident were so small as to be inconsequential compared with other forms of energy production—including fossil fuels, which produce carbon dioxide. But, he added, the AEC was not taking the issue seriously enough.

Weinberg would later regret his conversation with Nader. But the damage had been done. It fell to John Swartout, a former Weinberg deputy who was now the vice president for research at Union Carbide, which operated Oak Ridge under federal contract, to deliver the bad news. After 18 years as director of the world’s leading laboratory for research on advanced nuclear technology, Weinberg was out. The nuclear era he had envisioned, worked for, and espoused was placed on indefinite hold as of 1973.

That was the year everything changed. “The most pivotal year in energy history,” according to the U.S. Energy Information Administration.³³ It was the year the Arab oil sheikhdoms cut off supplies to the West, establishing the hegemony of the Organization of Petroleum-Exporting Countries (OPEC), and setting in motion the petroleum-fueled conflicts that still roil the world today. In 1973 the U.S. nuclear industry signed contracts for 41 new nuke plants—all were uranium-powered light-water reactors—the industry’s high-water mark and, although it was not apparent at the time, its final flourishing. No reactor ordered after 1973 was ever brought into operation. It was also the year that funding for the Clinch River Breeder Reactor began, having been approved by Congress a year previously. It would be canceled by Jimmy Carter after the Three Mile Island accident, briefly revived by the Reagan administration, and shelved for good in 1983.

In October, Egypt and Syria invaded Israel, triggering the Yom Kippur War and leading, with a grim inexorability, to the OPEC oil embargo that launched the first energy crisis and awoke Americans to the tenuousness of their energy sources. The following month Nixon announced “Project Independence,” calling for energy self-reliance by 1980—a goal centered on liquid metal breeder technology. It would come no closer to fulfillment than the Clinch River reactor project.

And it was the year that thorium-based molten salt reactors died, making thorium power one of the great what-ifs of the Atomic Age and taking with them Alvin Weinberg’s vision of a green and pleasant land dotted by safe, clean reactors.

Shaw was the next to go. In 1973, responding to environmentalists’ outcry, Nixon appointed Dixy Lee Ray, a marine biologist and former director of the Pacific Science Center, as chair of the AEC. Ray had little patience for Shaw’s Stalinist tactics or for the Navy’s old-boy network that dominated the industry, and she essentially removed nuclear safety from his purview. Furious, he resigned. Famous as the man who launched the Nautilus, he enjoyed a comfortable retirement as a consultant and a visiting professor at MIT and Carnegie-Mellon. Even as Three-Mile Island and Chernobyl poisoned public perceptions of nuclear power, he never publicly reconsidered his positions on reactor safety or on molten salt reactor technology.

Oddly his mentor did reconsider. In a 1984 interview with Diane Sawyer, President Jimmy Carter (himself a veteran of the Naval Reactors Branch) recalled a conversation he had with Admiral Rickover on one of the nuclear submarines he had helped create.

“I wish that nuclear power had never been discovered,” Rickover told his former junior officer. When Carter protested, “Admiral, this is your life,” Rickover replied, “I would forego all the accomplishments of my life, and I would be willing to forego all the advantages of nuclear power to propel ships, for medical research and for every other purpose of generating electric power, if we could have avoided the evolution of atomic explosives.”³⁴

For a man who never in his life second-guessed a decision he had made, this was a remarkable bit of self-reflection. In his public life, though, the bantam admiral had no time for such doubts. He resisted numerous attempts by Congress and successive administrations to oust him, and he clung to his naval career like a mariner clutching a tiller in a storm. He had seen the moment of his greatness flicker long before, but he refused to acknowledge the inevitable. When the end finally came, it was predictably unseemly. Accused by a Navy ethics board of accepting gifts from nuclear contractors, including General Dynamics and GE, Rickover clashed with Navy Secretary John Lehman, a distinguished former naval aviator who had come to view the “Rickover cult” as a major obstacle to renewing a service plagued by a loss of strategic vision, plummeting morale, and overly cozy relations with suppliers. In a now-famous Oval Office meeting with Lehman, President Ronald Reagan, and Defense Secretary Caspar Weinberger, Rickover called Lehman a “piss-ant” and a “Goddamn liar” and claimed to be “the only one in the government who keeps [the contractors] from robbing the taxpayers.”³⁵

All to no avail. Reagan informed the 83-year-old admiral that his career was over. Rickover spurned all ceremony and raised to the Navy that had been his life for more than 60 years the same finger that he’d given it since his days at Annapolis, two world wars ago. He died four years later and was buried in Arlington National Cemetery. It’s safe to say that his like will not tread the decks of the nation’s submarines again.

As for Alvin Weinberg, after a brief, stormy, and fruitless year in the capital as director of the newly created U.S. Office of Energy Research and Development—a federal appendage every bit as toothless as it sounds—he returned to distinguished exile in Oak Ridge to teach, write, and serve as the éminence grise of nuclear power for the rest of his life. His memoir contains a poignant recollection of his solitary late-night rambles through the streets of Washington during “the worst year of my life,” haunting the city like the ghost of a more enlightened and more promising age. His post-ORNL years were satisfying in many ways, but his biography is clearly that of a thwarted man. Near the end of his life (he died in 2006, at age 91), he spoke and wrote often of “the second nuclear era,” in which he never lost faith. He was a man of great foresight, moral force, and patience. His flaw was his idealism. He believed that science would rout ignorance, that reason would triumph over political might and personal ambition, and that his antagonists’ motives were as pure as his own. A more willful and ruthless man—a Rickover, or a Shaw—might have been able to see thorium molten salt breeders through to their eventual triumph.

“During my life I have witnessed extraordinary feats of human ingenuity,” Weinberg wrote. “I believe that this struggling ingenuity will be equal to the task of creating the Second Nuclear Era.

“My only regret is that I will not be here to witness its success.”³⁶