Flibe Energy Revives Thorium Reactor Nixon Shelved for Plutonium

Google TechTalks

Federal backing for fast breeders collapsed under non-proliferation bans after political horse-trading sidelined Alvin Weinberg's safer molten-salt technology.

AI-assisted summary of The Thorium Molten-Salt Reactor: Why Didn't This Happen (and why is now the right time?) — original source. Check the original for full context.

Source published: 2011-12-22

Key ideas

The United States prioritized the liquid-metal fast breeder reactor over Alvin Weinberg's molten-salt breeder primarily due to domestic political deal-making and regional job creation rather than technical merit. (11:40)
While Plutonium-239 requires unmoderated fast neutrons to exceed the critical breeding threshold of two, Thorium-derived Uranium-233 can sustain net breeding in a safer, thermal-neutron spectrum. (2:14)
The federal ban on commercial fuel reprocessing in the late 1970s crippled the fast breeder reactor's fuel supply, yet policymakers neglected to revive the thermal molten-salt alternative. (24:23)
Liquid Fluoride Thorium Reactors (LFTR) combine atmospheric low-pressure operation with high thermodynamic temperatures, utilizing passive freeze-plug drains to inherently prevent core meltdowns. (33:47)

Detailed notes

## Background This Google TechTalk was presented by Kirk Sorensen on December 16, 2011, and published to YouTube by the Google TechTalks channel on December 22, 2011. The presentation explores the history of the thorium molten-salt reactor, examining why the technology was historically abandoned and making the case for why modern energy demands make it the right time for its revival.

## TL;DR Nuclear engineer and Flibe Energy founder Kirk Sorensen investigates why the United States abandoned Alvin Weinberg's promising molten-salt thorium breeder reactor in the early 1970s. Sorensen details how Cold War politics, bureaucratic inertia, and backroom economic deals led federal leadership to channel hundreds of millions of dollars exclusively into plutonium-fueled liquid-metal fast breeders, only for that track to stall permanently after the 1970s non-proliferation bans on commercial reprocessing. Contending with contemporary post-Fukushima safety concerns and the immense baseload power required by modern digital infrastructure, Sorensen argues that liquid fluoride thorium reactors (LFTR) offer a safe, low-pressure, proliferation-resistant alternative to both fossil fuels and conventional light-water reactors.

## Atmosphere & style The presentation carries the measured, intellectually rigorous tone of an engineering lecture blended with an undercurrent of historical tragedy. Sorensen speaks with quiet conviction and dry irony, illustrating technical trade-offs with archival recordings and physics diagrams that underscore how short-sighted political bargaining derailed transformative science. Watching the talk feels like uncovering an alternative technological timeline, balancing deep frustration over decades of institutional neglect with earnest optimism for reviving Weinberg's liquid-fuel vision.

## Bulletin - [11:40](https://www.youtube.com/watch?v=bbyr7jZOllI&t=700s) The United States prioritized the liquid-metal fast breeder reactor over Alvin Weinberg's molten-salt breeder primarily due to domestic political deal-making and regional job creation rather than technical merit. - [02:14](https://www.youtube.com/watch?v=bbyr7jZOllI&t=134s) While Plutonium-239 requires unmoderated fast neutrons to exceed the critical breeding threshold of two, Thorium-derived Uranium-233 can sustain net breeding in a safer, thermal-neutron spectrum. - [24:23](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1463s) The federal ban on commercial fuel reprocessing in the late 1970s crippled the fast breeder reactor's fuel supply, yet policymakers neglected to revive the thermal molten-salt alternative. - [33:47](https://www.youtube.com/watch?v=bbyr7jZOllI&t=2027s) Liquid Fluoride Thorium Reactors (LFTR) combine atmospheric low-pressure operation with high thermodynamic temperatures, utilizing passive freeze-plug drains to inherently prevent core meltdowns.

## Key takeaways - [00:00](https://www.youtube.com/watch?v=bbyr7jZOllI&t=0s) Alvin Weinberg envisioned thorium molten-salt reactors as an abundant, clean power source capable of transforming global development through large-scale desalination and agriculture. - [02:14](https://www.youtube.com/watch?v=bbyr7jZOllI&t=134s) Continuous nuclear breeding requires a fissile material to exceed the 'Threshold of Two' net neutrons produced per neutron absorbed after accounting for non-fission captures. - [02:14](https://www.youtube.com/watch?v=bbyr7jZOllI&t=134s) Uranium-233 bred from Thorium is unique among nuclear fuels in its ability to cross the Threshold of Two in both thermal (slow) and fast neutron spectrums. - [04:50](https://www.youtube.com/watch?v=bbyr7jZOllI&t=290s) Plutonium-239 suffers excessive parasitic capture in a thermal spectrum, forcing American nuclear planners into developing fast-neutron reactors with high fissile inventories. - [07:20](https://www.youtube.com/watch?v=bbyr7jZOllI&t=440s) Solid-fuel fast breeders face a massive operational bottleneck in having to repeatedly remove, cool, reprocess, and refabricate highly radioactive solid fuel elements. - [10:42](https://www.youtube.com/watch?v=bbyr7jZOllI&t=642s) Federal funding was disproportionately skewed toward fast breeders, which received tens of millions annually while molten-salt development received negligible financial backing. - [11:40](https://www.youtube.com/watch?v=bbyr7jZOllI&t=700s) White House recordings reveal President Nixon pushed the fast breeder reactor largely to direct federal contracts and jobs to aerospace workers in Southern California. - [17:07](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1027s) AEC document WASH-1222 downplayed the safety advantages of molten salt, and Alvin Weinberg was ousted from Oak Ridge for persistently raising safety concerns about high-pressure light-water reactors. - [22:02](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1322s) India's 1974 nuclear test accelerated global non-proliferation concerns regarding plutonium separation, prompting Presidents Ford and Carter to ban domestic commercial reprocessing. - [27:00](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1620s) The light water breeder core at Shippingport successfully demonstrated a 1% net gain in fissile inventory, conclusively proving that thorium breeding in a thermal spectrum is physically viable. - [30:53](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1853s) Capital-intensive and intermittent renewables like solar struggle to economically match the dense, baseload power demands of modern infrastructure, leading society to default to coal. - [33:47](https://www.youtube.com/watch?v=bbyr7jZOllI&t=2027s) Molten fluoride salt operates simultaneously at high temperatures and atmospheric low pressure, providing passive drain safety and immunity to radiation damage. - [33:47](https://www.youtube.com/watch?v=bbyr7jZOllI&t=2027s) Commercializing the LFTR faces primary hurdles not in fundamental physics, but in managing material corrosion and navigating a regulatory framework built strictly for solid-fuel water reactors.

## Detailed walkthrough ### [00:00](https://www.youtube.com/watch?v=bbyr7jZOllI&t=0s) Introduction and Alvin Weinberg's Vision

A host named Chris introduces Kirk Sorensen, founder of Flibe Energy and long-time champion of thorium power through his work with energyfromthorium.com, a global community of experts and enthusiasts collaborating to determine the optimal thorium-based nuclear reactor. Chris notes that while thorium technology originated shortly after World War II and matured through the early 1970s, it was abruptly abandoned in favor of the liquid-metal fast breeder reactor (LMFBR)—which itself was eventually canceled. Kirk Sorensen begins by addressing the central question he encounters at nearly every speaking engagement: “Kirk, Thorium sounds like a great idea. It sounds like it's a good technology, why didn’t this happen?”

Sorensen explains that Flibe Energy was established to develop liquid fluoride thorium reactor (LFTR) technology based on the pioneering work of Dr. Alvin Weinberg, the director of Oak Ridge National Laboratory from 1955 to the early 1970s. Weinberg envisioned thorium as a pathway to liberate humanity from the constraints of fossil fuels, finite hydroelectric resources, and standard solid-fuel nuclear reactors. In Weinberg’s broader humanitarian outlook, cheap and abundant thorium energy would transform global economies—particularly resource-constrained regions lacking fresh water or arable land—by enabling large-scale seawater desalination and desert agriculture, effectively terraforming parts of the Earth. However, Weinberg's program was terminated in the early 1970s, setting up the central historical and technical puzzle of the presentation.

[02:14](https://www.youtube.com/watch?v=bbyr7jZOllI&t=134s) The Three Nuclear Fuels and the Threshold of Two

Sorensen traces the dilemma back to the dawn of the atomic age, when nuclear physicists evaluated three primary fuel options: Uranium-235, Uranium-238, and Thorium-232. Of these, only Uranium-235 is fissile in nature and capable of being directly split to sustain a chain reaction. Uranium-238 and Thorium-232 are fertile materials that cannot fission directly; each must absorb a neutron to transmute into a fissile isotope—Plutonium-239 and Uranium-233, respectively. Because breeding requires one neutron to convert the fertile atom and a second neutron to induce fission in the bred atom, any continuous breeding cycle demands that each fission event produce strictly more than two neutrons.

```mermaid flowchart TD accTitle: Nuclear Fuel Breeding and Fission Cycles accDescr: Diagram contrasting the transmutation and fission pathways of Uranium-238 and Thorium-232.

All three fissile fuels nominally meet this baseline: Uranium-235 emits roughly 2.4 neutrons per fission, Uranium-233 emits approximately 2.5, and Plutonium-239 emits nearly 3.0 neutrons per fission. However, raw neutron emission does not account for parasitic absorption (neutrons absorbed by the fuel without causing fission). When accounting for non-fission captures, Sorensen defines what he terms the "Threshold of Two"—the net yield of neutrons produced per neutron absorbed:

- In a thermal (moderated, slow-neutron) spectrum, Plutonium-239 drops below the Threshold of Two because it frequently absorbs thermal neutrons without fissioning. - Plutonium-239 can only exceed the Threshold of Two when struck by unmoderated, high-energy fast neutrons. - In contrast, Uranium-233 derived from Thorium crosses the Threshold of Two in both thermal and fast neutron spectrums, offering the unique possibility of breeding fuel using slow neutrons.

[04:50](https://www.youtube.com/watch?v=bbyr7jZOllI&t=290s) Neutron Cross-Sections and the Fast vs. Thermal Dilemma

Sorensen explains why crossing the Threshold of Two in a thermal spectrum matters so profoundly by examining nuclear cross-sections—the mathematical probability that a given nuclear interaction will occur, measured in barns ($10^{-24}\text{ cm}^2$). Across almost all nuclear materials, cross-sections are orders of magnitude larger for slow thermal neutrons than for fast neutrons. A thermal neutron sees an enormous target area when approaching a Uranium-233 or Plutonium-239 nucleus, making a reaction far more likely to occur than with a fast neutron, where the interaction cross-section shrinks dramatically.

This physical reality initially creates a strong bias toward thermal reactors. However, parasitic capture complicates the picture: in the thermal spectrum, Plutonium-239 absorbs a neutron without fissioning roughly one-third of the time, effectively wasting the neutron and preventing sustainable breeding. By contrast, Uranium-233 undergoes non-fission capture only about 10% of the time in the thermal range. In the fast spectrum, parasitic capture drops to near zero for both fuels; if a fast neutron strikes either nucleus and is absorbed, it almost invariably triggers fission. Because Plutonium-239 cannot sustain a breeding cycle in a thermal spectrum, American nuclear planners concluded that breeding fuel from abundant Uranium-238 strictly mandated the development of fast-neutron reactors.

- Cross-sections quantify reaction probability in units of barns ($10^{-24}\text{ cm}^2$). - Thermal neutrons provide vastly higher reaction probabilities, requiring substantially smaller fissile inventories to achieve criticality. - Fast reactors require significantly higher concentrations of fissile material in the core because the probability of interaction per pass is exceedingly low. - Plutonium-239 must be deployed in a fast spectrum to avoid parasitic capture, whereas Uranium-233 can sustain net breeding in a simple, well-moderated thermal spectrum.

[07:20](https://www.youtube.com/watch?v=bbyr7jZOllI&t=440s) The Fast Breeder Track and Weinberg's Liquid-Fuel Counter-Vision

Driven by the imperative to breed Plutonium from Uranium-238, the United States committed early and heavily to the fast breeder reactor. In 1951, the Experimental Breeder Reactor I (EBR-I) in Idaho achieved criticality, becoming the first reactor to generate usable electricity by lighting four lightbulbs and eventually producing several hundred kilowatts. This was succeeded by the 62-megawatt thermal Experimental Breeder Reactor II (EBR-II). Commercial industry embraced the concept, culminating in the construction of the Enrico Fermi Fast Breeder Reactor in Monroe, Michigan, which began development in 1957 and went critical in 1966. However, Fermi 1 suffered a partial core meltdown shortly after startup due to a coolant blockage, forcing a prolonged shutdown and dealing a severe blow to commercial fast breeder momentum.

During this same era, Alvin Weinberg and his team at Oak Ridge National Laboratory were quietly pursuing the Molten-Salt Reactor Experiment (MSRE), relying on thermal-spectrum neutrons and the Thorium/Uranium-233 cycle. In his 1969 introductory preface to a dedicated series of papers in *Nuclear Applications and Technology*, Weinberg highlighted the fundamental pitfall of solid-fuel fast breeders:

> “The prevailing view holds that the liquid-metal fast breeder reactor is the proper path to ubiquitous permanent energy. It is no secret that I, as well many of my colleagues at Oak Ridge, have always felt differently. When the idea of the breeder was first suggested in 1943, the rapid and the efficient recycle of the partially spent core was regarded as the main problem. Nothing that has happened in the ensuing quarter century has fundamentally changed this.”

Weinberg argued that solid-fuel fast breeder reactors faced an insurmountable bottleneck in having to remove, cool, chemically reprocess, and refabricate highly radioactive solid fuel elements after only a fraction of the fuel had burned. To overcome this, Weinberg asserted: “The successful breeder will be the one that can deal with the spent fuel or the spent core most rationally either by achieving extremely long burn up or by greatly simplifying the entire recycle step.” Sorensen emphasizes that this logic guided Oak Ridge away from solid fuel rods toward liquid-fueled systems: “We at Oak Ridge, have always been intrigued by this latter possibility. It explains our long commitment to liquid fuel reactors, first, the Aqueous Homogeneous and now the Molten-salt.”

[10:42](https://www.youtube.com/watch?v=bbyr7jZOllI&t=642s) Federal Budget Disparities: Fast Breeder vs. Molten-Salt Breeder

Kirk Sorensen explains that the research appropriations allocated to the different breeder reactor concepts paint a stark picture. Drawing data from a historical book digitized through Google Books—a project initiated by his friend Chris Yunkins—Sorensen converted the raw figures into a spreadsheet and plotted a comparative timeline. Starting around 1968, by which point the United States had already constructed several fast breeder reactors, expenditures on the fast breeder reactor were commanding between $75 million and nearly $100 million annually.

```mermaid flowchart LR accTitle: Federal Reactor Appropriations Contrast accDescr: Visual comparison between federal backing of the liquid metal fast breeder reactor versus the molten salt breeder reactor.

subgraph LMFBR["Liquid-Metal Fast Breeder (LMFBR)"] A["1968: $75M–$100M/year"] --> B["Major AEC & Congressional Priority"] B --> C["1972: Projected >$700M Dev Cost"] end

subgraph MSBR["Molten-Salt Breeder (MSBR)"] D["Barely visible funding"] --> E["Cancelled (Early 1970s)"] E --> F["Brief 1975 revival, then permanent cancellation"] end ```

By contrast, the molten-salt breeder reactor funding line is virtually invisible along the bottom axis of the chart. The molten-salt program received minuscule funding before being canceled outright, experiencing a brief resurrection in 1975, and then being canceled once again. On the scale of national nuclear appropriations, federal commitment was directed almost exclusively toward liquid-metal fast breeder reactors.

[11:40](https://www.youtube.com/watch?v=bbyr7jZOllI&t=700s) Nixon’s Backroom Deals and the Politics of the Fast Breeder

In June 1971, President Richard Nixon delivered an address designating the fast breeder reactor as a top national priority. Although no video footage of the speech survives, Nixon was captured on his White House taping system later that day in a private telephone discussion with Representative Craig Hosmer of California, a prominent member of the Joint Committee on Atomic Energy. Sorensen plays the original audio recording, in which Nixon reveals that his aggressive push for breeder reactor funding had far less to do with the comparative technical merits of different reactor types than with delivering jobs and economic patronage to Southern California's struggling aerospace workforce.

Nixon bluntly instructed Hosmer to coordinate with Representative Chet Holifield, also of California, to steer federal energy projects back to their home state: “The one thing I wanted to tell you too is that, I--Holifield was there last night at the [INDISTINCT] Club thing, and I--and I have told the people around here--now, this is got to be something we play very close to the vest, but I'm being ruthless on one thing, any activities that we possibly can, should be placed in southern California in this field.” Nixon told Hosmer to repeatedly pressure AEC leadership—including science adviser Edward David Jr. and AEC Chairman Glenn Seaborg—asking, "Where is this going to be?" to lock down California sites. When Hosmer expressed gratitude for a $16 million appropriation toward an enrichment facility that resolved a local political problem, Nixon responded in kind: "Well, they told me you were interested in it, and I said, 'Well, if Hosmer is for it, I'm for it.'"

- The primary political actors coordinating on the initiative were Californians: President Nixon, Representative Craig Hosmer, and Joint Committee on Atomic Energy leader Chet Holifield. - Nixon paired his breeder push with promises of saline water desalination plants targeted specifically to generate Southern California employment. - As Sorensen observes, the archival conversation reflects an administration focused strictly on electoral politics and local jobs rather than an objective technical assessment of alternative reactor chemistries.

[14:28](https://www.youtube.com/watch?v=bbyr7jZOllI&t=868s) Hanford Address and the Escalating National Commitment

A few months after the phone call with Hosmer, Nixon traveled to the Hanford nuclear reservation in Washington state—one of the earliest and most storied nuclear production sites in the nation—to deliver another speech on the breeder reactor. Sorensen notes the irony of the venue: Hanford was populated by some of the most scientifically literate nuclear specialists and PhDs in the country, yet Nixon framed the entire reactor initiative in simplistic economic terms while openly self-deprecating about his own scientific ignorance.

During the Hanford speech, Nixon placed the breeder initiative alongside the historic diplomatic opening to China and his domestic economic wage-and-price programs, admitting: “Now, don't ask me what a breeder reactor is, ask Dr. Schlesinger, but don't tell, I'm not to tell you because unless you're one of those PhDs, you won't understand it either.” He admitted that science had been one of his poorest academic subjects, having abandoned it as a college sophomore because it required too much effort, but insisted that the breakthrough represented by breeder technology meant "jobs, jobs for this area but jobs and power for hundreds from millions of people all over the world." Sorensen laments that the nation might have been far better served had its leadership understood the fundamental physical and safety differences among breeder designs before committing the country to a singular path.

- Nixon elevated the fast breeder reactor into his formal State of the Union address and subsequent messages to Congress. - By 1972, both the Democratic and Republican party platforms formally incorporated the fast breeder reactor as a paramount national priority. - By September 1972 congressional testimony, projected development costs for the liquid-metal fast breeder reactor had escalated past $700 million, on top of $200 million already committed by private industry. - Facing these steep projections, Representative Craig Hosmer signaled unconditional legislative backing, telling committee members: “If cost targets were missed, I for one don't intend to scream and holler about it.”

[17:07](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1027s) WASH-1222, Milton Shaw, and the Ousting of Alvin Weinberg

The broader political and budgetary juggernaut behind the liquid-metal fast breeder reactor soon collided directly with Alvin Weinberg and his research team at Oak Ridge National Laboratory. In September 1972, the Atomic Energy Commission published document WASH-1222, an official technical evaluation of Weinberg’s molten-salt breeder concept. WASH-1222 offered sharp critiques of the unresolved engineering hurdles associated with molten salt, while systematically downplaying or omitting the enormous safety and economic benefits that the fluid-fuel, low-pressure system possessed over high-pressure water and liquid-metal systems.

Inside the AEC, the Division of Reactor Development and Technology was led by Milton Shaw, a hard-charging protégé of Admiral Hyman Rickover. In his autobiography, *The First Nuclear Era*, Weinberg recalled the escalating friction between Oak Ridge and Shaw's office: “Milt tackled the LMFBR project with Rickoverian dedication: woe unto any who stood in his way.” Backed by unassailable support from the Joint Committee on Atomic Energy, Shaw harbored little patience for Oak Ridge's advocacy of thorium and molten salt. More critically, Weinberg had begun vocally raising reactor safety issues concerning pressurized light-water reactors—which he had originally invented—arguing that molten-salt reactors offered far superior intrinsic safety because they did not store massive amounts of energy under high pressure.

```mermaid flowchart TD accTitle: Weinberg AEC Conflict Flowchart accDescr: Progression of political and administrative resistance leading to Alvin Weinberg being pushed out of nuclear energy.

subgraph Bureaucracy["Washington Nuclear Power Base"] Nixon["President Richard Nixon (Prioritizes California Jobs)"] Holifield["Rep. Chet Holifield (Joint Committee on Atomic Energy)"] Shaw["Milton Shaw (AEC Reactor Division / LMFBR Champion)"] end

subgraph OakRidge["Oak Ridge National Laboratory"] Weinberg["Alvin Weinberg"] Safety["Concerns over High-Pressure LWRs"] MSBR["Promotion of Low-Pressure Molten-Salt"] end

This persistent safety advocacy broke Weinberg's standing with congressional leadership. During a closed meeting in 1972 between Weinberg, Milton Shaw, and Joint Committee leader Chet Holifield, Holifield’s patience ran out entirely. Weinberg recorded the confrontation: “Congressman Chet Holifield was clearly exasperated with me and he finally blurted out, 'Alvin, if you're so concerned about the safety of reactors, then I think it might be time for you to leave nuclear energy.'” Weinberg was left stunned, realizing his vision for reactor safety and thorium technology had made him an outcast among the officials steering the nation's nuclear trajectory—a turning point Sorensen describes as a tragic missed opportunity for American energy history.

[20:29](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1229s) The Ouster of Alvin Weinberg and Cancellation of the Molten-Salt Program

Alvin Weinberg’s dismissal from his post as director of the Oak Ridge National Laboratory culminated from an escalating friction with influential leaders inside the Atomic Energy Commission (AEC) and Congress, most notably the formidable Representative Chet Holifield. In his 1994 autobiography, Weinberg reflected on his removal with philosophical poise rather than bitterness. As Kirk Sorensen recounts, Weinberg wrote: “I look back in these events, I realize that leaving Oak Ridge was the best thing that could have happened to me. My views about nuclear energy were at variance with those of the AEC congressional leadership. After all, it was I who had called nuclear energy a Faustian bargain, who continued to promote the molten-salt breeder.” Weinberg’s championing of thorium had directly collided with a well-entrenched, well-funded political and industrial coalition committed entirely to the plutonium-fueled liquid metal fast breeder reactor (LMFBR).

Faced with Weinberg’s stubborn advocacy for an alternative path, the establishment moved decisively to terminate the competing concept. In January 1973, the AEC officially ordered Oak Ridge to shut down all development of the molten-salt reactor. Just months later, in April 1973, President Richard Nixon reaffirmed his administration’s absolute devotion to the fast breeder, announcing that it could harvest thirty times more energy from uranium than conventional light water reactors and designating it the nation’s highest-priority nuclear energy research initiative. Adding pressure to the American program, international rivals were moving rapidly; in August 1973, France’s Phénix fast breeder reactor went critical. The achievement fueled an intense American desire to dominate the fast breeder sector, eclipsing any appetite for unconventional designs like the molten-salt reactor.

- In January 1973, the Atomic Energy Commission formally ordered Oak Ridge National Laboratory to terminate molten-salt reactor development. - In April 1973, Richard Nixon publicly highlighted the fast breeder as the number-one nuclear research priority, emphasizing its potential to extract thirty times more energy from uranium. - In August 1973, France reached criticality with its Phénix liquid metal fast breeder reactor, intensifying geopolitical pressure on the United States to stay ahead.

---

[22:02](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1322s) The 1973 Oil Crisis, Project Independence, and the Indian Nuclear Test

Later in 1973, global geopolitics upended the American energy conversation when the Yom Kippur War broke out, triggering the OPEC oil embargo. The sudden curtailment of crude oil supplies produced economic shockwaves throughout the United States: motorists queued for hours in serpentine lines at filling stations, local regulations forced drivers to alternate fuel purchases based on odd or even license plate numbers, workers found themselves unable to commute, and major swaths of commercial activity ground to an abrupt halt. Under severe public and political pressure, Nixon launched Project Independence, an aggressive national blueprint intended to achieve complete energy self-sufficiency by 1980. The proposal called for an unprecedented domestic construction blitz of fast breeder reactors, light water reactors, oil drilling operations, refineries, and coal mines. However, when the embargo lifted in March 1974, political urgency evaporated, and the sweeping mandates of Project Independence quietly stalled.

Shortly after the embargo subsided, another geopolitical shock reshuffled American nuclear policy: in May 1974, India detonated an explosive nuclear device fabricated using plutonium that had been chemically separated from natural uranium irradiated inside an imported heavy-water research reactor. The blast triggered widespread alarm across the United States government regarding the proliferation vulnerabilities of fuel reprocessing plants, which separated weapons-usable plutonium from irradiated reactor fuel. While technical arguments maintained that reactor-grade plutonium from standard commercial light water reactors was ill-suited for reliable weapons manufacture compared to weapons-grade plutonium, the fear of diversion hardened. This presented an existential dilemma for the fast breeder reactor, whose entire operational concept relied upon chemical reprocessing to extract spent fuel plutonium from light water reactors to manufacture its initial fissile cores. Because the fission cross-section for plutonium is dramatically smaller in a fast-neutron spectrum than in a thermal-neutron spectrum, a fast breeder requires an enormous physical inventory of fissile fuel simply to reach criticality and begin operating, making its commercial viability completely dependent on an active civilian reprocessing industry.

```mermaid flowchart TD accTitle: Fast Breeder Reliance on Fuel Reprocessing accDescr: Chart illustrating how light water reactor spent fuel feeds fast breeder startup cores and how the non-proliferation ban severed that fuel cycle.

subgraph LWR ["Light Water Reactor Fleet"] A["Uranium Fuel"] --> B["Spent LWR Fuel"] end

subgraph Reprocess ["Chemical Reprocessing Facility"] B --> C["Plutonium Separation"] end

subgraph Breeder ["Fast Breeder Reactor"] C -->|"Large Fissile Mass (Low Fast Cross-Section)"| D["FBR Startup Core"] D --> E["Breeds New Fuel"] end

subgraph Policy ["1970s Non-Proliferation Shift"] F["1974 Indian Nuclear Test"] -.->|"Triggers Proliferation Fears"| G["Reprocessing Ban (Ford / Carter)"] G -.->|"Severed Feedstock Supply"| C end ```

---

[24:23](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1463s) Political Realignment, the Reprocessing Ban, and the Carter Presidency

Following Nixon's resignation in August 1974, Gerald Ford assumed the presidency and restructured the atomic bureaucracy, breaking up the Atomic Energy Commission into the Nuclear Regulatory Commission (NRC) and the Energy Research and Development Administration (ERDA), which would later become the Department of Energy. Simultaneously, Congress abolished the once-omnipotent Joint Committee on Atomic Energy, ending Chet Holifield’s era of unchallenged oversight. Ford nevertheless maintained robust backing for the fast breeder reactor, defending it in State of the Union addresses, expanding its R&D budgets, and arguing that fast breeders could unlock centuries of energy from domestic uranium reserves.

As the razor-thin presidential election of 1976 approached, Democratic nominee Jimmy Carter campaigned aggressively against domestic nuclear reprocessing, citing global non-proliferation concerns. In a bid to defang Carter's platform barely a week before Election Day, on October 28, 1976, President Ford made a dramatic policy reversal and adopted his opponent's stance. Ford announced: “We are not going to reprocess Uranium anymore. We're not going to separate Plutonium,” grounding his sudden prohibition directly in the hazards of international nuclear proliferation.

When Carter assumed office in 1977, the centerpiece of the nation’s nuclear expansion was a planned demonstration fast breeder reactor slated for construction along the Clinch River in Tennessee, adjacent to Oak Ridge. Carter opposed the project, arguing that institutional fixation on the fast breeder had drained capital and intellectual bandwidth away from alternative clean technologies like solar power. Denouncing the trajectory that would transform America into a hazardous “plutonium society,” Carter confirmed Ford’s reprocessing ban as enduring federal policy and moved to cut funding for the Clinch River Breeder Reactor, declaring: “There's no need to enter the Plutonium age by licensing or building a fast breeder reactor such as the proposed demonstration plan at Clinch River.”

- Gerald Ford split the AEC into the Nuclear Regulatory Commission (NRC) and the Energy Research and Development Administration (ERDA, the forerunner to the DOE). - The Joint Committee on Atomic Energy, long chaired and directed by Chet Holifield, was abolished during the Ford presidency. - On October 28, 1976, Ford preempted Carter’s campaign message by ordering a halt to domestic commercial reprocessing and plutonium extraction. - In 1977, Jimmy Carter upheld the commercial reprocessing moratorium, sought budget cuts for the Clinch River Breeder Reactor, and redirected national energy priorities toward coal and solar.

---

[27:00](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1620s) The Shippingport Success, Three Mile Island, and the Forgotten MSR Legacy

Despite his skepticism toward plutonium fast breeders, Jimmy Carter harbored a unique appreciation for thorium breeding, stemming from his early career in the nuclear navy under Admiral Hyman Rickover. At that very moment, Rickover’s Naval Reactors branch was completing an experimental conversion of the Shippingport Atomic Power Station in Pennsylvania, retrofitting its core with thorium dioxide and uranium-233 dioxide ($ThO_2 / {}^{233}UO_2$). President Carter was given the honor of flipping the switch that energized the first and only thorium breeder reactor in United States history, openly expressing his desire to explore uranium-thorium breeding cycles as a proliferation-resistant alternative to plutonium.

Shippingport operated for five years until its scheduled shutdown in 1982. Post-operation core examinations revealed that it contained 1% more fissile material at the end of its life than when it had started. While Shippingport was a solid-fueled light water breeder rather than a molten-salt liquid-fueled design, it conclusively validated the underlying physics: breeding fuel with thorium in a thermal-neutron spectrum was an accomplished, physical fact.

``` +--------------------------------------------------------------------------------------------------+ | Chronology of US Breeder Reactor Policy | +------+-------------------------------------------------------------------------------------------+ | Year | Event | +------+-------------------------------------------------------------------------------------------+ | 1973 | AEC cancels the Molten-Salt Reactor Experiment; Nixon recommits heavily to fast breeders. | | 1974 | India's test prompts proliferation panic; Ford divides the AEC into NRC and ERDA. | | 1976 | Ford bans commercial fuel reprocessing and plutonium separation right before election. | | 1977 | Carter reinforces reprocessing ban, attacks the "Plutonium society" and Clinch River. | | 1977 | Carter switches on the Thorium/U-233 Light Water Breeder Reactor at Shippingport. | | 1979 | Three Mile Island partial meltdown cripples public confidence in commercial nuclear power.| | 1982 | Shippingport core harvested, demonstrating a 1% net gain in fissile material. | | 1982 | Reagan signs Nuclear Waste Policy Act, cementing the once-through geologic disposal path.| +------+-------------------------------------------------------------------------------------------+ ```

The broader commercial nuclear industry, however, faced catastrophic headwinds. The 1979 partial meltdown at Three Mile Island decimated public trust in light water reactors. Even after Ronald Reagan took office in 1981 and overturned the federal prohibition on commercial reprocessing, private industry declined to risk capital building commercial reprocessing plants. Because the fast breeder had been legally divorced from its fuel supply, a new strategy was required for spent commercial fuel; Reagan subsequently signed the Nuclear Waste Policy Act of 1982, locking the nation into a once-through fuel cycle and setting up long-term geologic storage at repositories like Yucca Mountain.

Curiously, federal funding for fast breeder research had peaked between 1976 and 1980 under Carter, persisting through sheer bureaucratic momentum long after the underlying fuel cycle had been banned. The AEC had originally bet on plutonium because its fast-spectrum neutron yield safely surpassed the threshold of two, making it seem a guaranteed breeding success compared to thorium's narrower thermal margins. But once the reprocessing ban destroyed the fast breeder's rationale, Washington policymakers never stopped to reconsider the abandoned alternative. Nobody asked if canceling the molten-salt reactor had been a profound mistake or whether the nation should pivot to Weinberg's thermal-spectrum molten-salt breeder. Instead, the seasoned Oak Ridge team disbanded, their facilities were shuttered, and the institutional knowledge built over decades was gradually forgotten.

---

[30:15](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1815s) Reassessing the Liquid Fluoride Thorium Reactor for the Modern Era

Kirk Sorensen brings the narrative to 2011 to examine why the modern embodiment of the molten-salt concept—the Liquid Fluoride Thorium Reactor (LFTR)—is urgently needed today. Humanity confronts an unprecedented dual challenge: supplying vast quantities of cheap, abundant energy to support human flourishing while simultaneously curtailing environmental destruction. The acute threats of global climate change, melting polar glaciers, rising sea levels, and destabilized weather patterns demand rapid, drastic reductions in greenhouse gas emissions. Yet, legacy nuclear technology remains stalled by persistent public distrust and entrenched safety anxieties, making a fundamental re-evaluation of thorium molten-salt technology more imperative than ever before.

[30:53](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1853s) The High-Density Energy Challenge: Data Centers, Solar Limits, and the Coal Default

Following the Fukushima Daiichi disaster, public perception of nuclear power shifted dramatically despite the fact that no direct fatalities occurred from radiation at the site. Kirk Sorensen observes that media coverage and prevailing public sentiment have forced people to question conventional light-water reactors, underscoring the urgent need for an alternative reactor design that avoids high-pressure fluids and eliminates the risk of catastrophic meltdowns. At the same time, relying entirely on fossil fuels causes immense ecological damage across extraction, processing, atmospheric emissions, and fuel transportation, while building long-distance electrical transmission lines remains prohibitively expensive.

```mermaid flowchart TD accTitle: Modern Energy Demand vs Generation Options accDescr: Diagram contrasting data center power requirements with solar limitations and the default coal fallback. subgraph Demand["Modern Concentrated Demand"] A["Facebook Data Center (Luleå, Sweden)"] A --- DemandSpec["Needs: 120 MW continuous 14 diesel backups (40 MW)"] end

subgraph GreenSupply["Diffuse Renewable Alternative"] B["Spanish Solar Farm (185 hectares)"] B --- SolarSpec["Produces: 20 MW peak (15 hrs/day) Cost: $420M (~$33/watt)"] B -.->|"Requires 10+ sites & intercontinental grid"| A end

subgraph CoalDefault["Current Economic Fallback"] C["German Lignite Coal Plant (1600 MW continuous)"] C ==>|"Easily powers 13 data centers (Cheap, dirty, reliable)"| A end ```

To illustrate the immense, highly concentrated appetite of modern digital society, Sorensen points to Facebook’s massive data center built roughly one hundred miles south of the Arctic Circle in Sweden. The facility consumes 120 megawatts of continuous hydropower, backed by 14 emergency diesel generators delivering 40 megawatts, at a construction cost of $760 million. By contrast, one of the world’s largest solar installations in Spain spans 185 hectares, cost $420 million, and generates just 20 megawatts of peak power for 15 hours a day—equating to roughly $33 per watt, which is six to seven times the capital expense of conventional generation. Powering that single Swedish data center on solar alone would demand at least ten such Spanish facilities alongside transcontinental transmission links crossing Europe from sunny Spain to frozen Sweden.

Because such diffuse renewable schemes face severe physical and economic hurdles, Sorensen argues that society inevitably defaults to dense, dispatchable fossil generation. Highlighting a massive 1,600-megawatt lignite-burning facility in Germany, he quips with dry irony that it is the prettiest coal plant he has ever seen, noting that a single such plant could power thirteen of those Swedish data centers effortlessly. Yet for the global environment, this fallback is catastrophic. As Sorensen emphasizes:

> “If we try to use expensive intermittent and alternative energy, it's not going to be the answer.”

- **Facebook Swedish Data Center**: Located 100 miles south of the Arctic Circle; draws 120 MW continuously; utilizes 14 backup diesel generators producing 40 MW emergency power; capital cost of $760 million. - **Spanish Solar Facility**: Spans 185 hectares; yields 20 MW peak power for 15 hours per day; capital cost of $420 million (~$33/watt peak), requiring at least 10 equivalent installations plus long-distance transmission to match a single modern server facility. - **German Lignite Coal Plant**: Produces 1,600 MW of reliable, baseload power—enough to run 13 hyper-scale data centers, illustrating why developing and industrial nations default to cheap fossil generation over unsubsidized renewables.

---

[33:47](https://www.youtube.com/watch?v=bbyr7jZOllI&t=2027s) The Molten-Salt Solution, Technical Merits, and Key Challenges

The fundamental dilemma facing the globe is that most populations cannot afford unsubsidized, intermittent energy; without an alternative, they will inevitably select cheap, dirty, and reliable coal. Sorensen contends that natural, abundant, and energy-dense thorium offers the genuine solution to this crisis, provided the right machine is built to harness it. Molten fluoride salt serves as the ideal reactor medium because it is the only coolant option among the four classic reactor cooling classes capable of running simultaneously at atmospheric low pressure and elevated high temperatures, which maximizes thermodynamic conversion efficiency.

```mermaid flowchart LR accTitle: Passive Safety and Core Attributes of LFTR accDescr: Flow diagram showing how molten fluoride salt enables passive drain safety, high efficiency, and proliferation resistance. subgraph CoreAttributes["Fluid Fuel & Fluoride Matrix"] A["Liquid Fluoride Salt (LiF-BeF2-ThF4-UF4)"] --> B["Low Pressure Operation & High Temp Heat"] A --> C["Radiation Impervious & No Fuel Fabrication"] end

subgraph Operation["Safety & Fuel Cycle"] B --> D["Passive Freeze-Plug Drain to Subcritical Tanks"] B --> E["High Thermodynamic Efficiency"] C --> F["Unlimited Burnup & Core-to-Blanket Reprocessing"] end

subgraph Safeguards["Proliferation Resistance"] F --> G["U-233 contaminated with U-232 (Hard gamma emitter, easy down-blending)"] end ```

Liquid fuel architectures also introduce self-acting safety mechanisms entirely unavailable to solid-fueled reactors. In any power outage or emergency excursion, the molten salt simply thaws a freeze plug and drains by gravity into passive, passively cooled holding tanks beneath the vessel, preventing meltdowns by design. Fluoride chemistry forms a near-perfect union with the thorium fuel cycle: the salts remain chemically stable under intense bombardment, suffer zero radiation-induced structural swelling, eliminate fuel fabrication and cladding expenses, and permit continuous processing between the active core and fertile blanket. Furthermore, the bred Uranium-233 is inherently protected against weapons proliferation due to co-produced Uranium-232, whose energetic gamma daughters render the material dangerous to handle and straightforward to detect or down-blend.

Sorensen candidly addresses the remaining engineering obstacles, notably the corrosive aggressiveness of hot salts against conventional metals, which requires specialized nickel-base alloys like Hastelloy-N. However, the most formidable barriers are regulatory and institutional rather than physical. Because reactor technology has stagnated around solid-fuel, high-pressure light-water reactors for over four decades, the existing nuclear establishment and regulatory frameworks are built around paradigms foreign to liquid-fluoride systems. Overcoming this inertia demands broad public and industry education. In closing, Sorensen states that his company, Flibe Energy, is dedicated to overcoming these hurdles and commercializing liquid fluoride thorium reactors (LFTR) worldwide. As Sorensen reflects on the unique nature of the reactor's primary coolant:

> “Because molten-salt is the only one of the four potential coolants in the reactor that can run at both high temperature and low pressure.”

- **Passive Drain Safety**: In emergencies, freeze valves melt without external power or operator intervention, draining the liquid core into subcritical, naturally convecting dump tanks. - **Fuel Cycle Economics**: Completely bypasses solid fuel element manufacturing, fuel enrichment, and high-pressure containment vessels while enabling near-complete consumption of fertile thorium through continuous online processing. - **Nonproliferation Attributes**: Breeding yields Uranium-233 tainted with trace Uranium-232; the high-energy 2.6 MeV gamma emissions from daughter isotope Thallium-208 make diversion and weapons fabrication exceptionally difficult. - **Key Developmental Hurdles**: Addressing metal corrosion and high-temperature stress through specialized materials, reviving technical know-how lost after 40 years of stagnation, and adapting a regulatory environment designed exclusively for light-water reactors.

## Notable quotes > [07:20](https://www.youtube.com/watch?v=bbyr7jZOllI&t=440s) The successful breeder will be the one that can deal with the spent fuel or the spent core most rationally either by achieving extremely long burn up or by greatly simplifying the entire recycle step. — Alvin Weinberg

> [30:53](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1853s) If we try to use expensive intermittent and alternative energy, it's not going to be the answer. — Kirk Sorensen

> [24:23](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1463s) There's no need to enter the Plutonium age by licensing or building a fast breeder reactor such as the proposed demonstration plan at Clinch River. — Jimmy Carter

## Mentioned Kirk Sorensen, Alvin Weinberg, Flibe Energy, energyfromthorium.com, Oak Ridge National Laboratory, Liquid Fluoride Thorium Reactor (LFTR), Liquid-Metal Fast Breeder Reactor (LMFBR), Experimental Breeder Reactor I (EBR-I), Experimental Breeder Reactor II (EBR-II), Enrico Fermi Fast Breeder Reactor, Molten-Salt Reactor Experiment (MSRE), Nuclear Applications and Technology, Richard Nixon, Craig Hosmer, Chet Holifield, Joint Committee on Atomic Energy, Atomic Energy Commission (AEC), Edward David Jr., Glenn Seaborg, Hanford Site, James R. Schlesinger, WASH-1222, Milton Shaw, Hyman Rickover, The First Nuclear Era, Phénix, Project Independence, Gerald Ford, Nuclear Regulatory Commission (NRC), Energy Research and Development Administration (ERDA), Department of Energy, Jimmy Carter, Clinch River Breeder Reactor, Shippingport Atomic Power Station, Ronald Reagan, Nuclear Waste Policy Act of 1982, Yucca Mountain, Facebook, Hastelloy-N

## Video description Google Tech Talk December 16, 2011

Presented by Kirk Sorensen

[Source](https://www.youtube.com/watch?v=bbyr7jZOllI)

中文简报

Flibe Energy重启曾被尼克松搁置的钍反应堆技术在政治利益交换导致阿尔文·温伯格更安全的熔盐技术被边缘化后，联邦对快中子增殖堆的支持因核不扩散禁令而瓦解。核工程师兼Flibe Energy创始人柯克·索伦森探讨了美国在20世纪70年代初为何放弃阿尔文·温伯格前景广阔的熔盐钍增殖反应堆。索伦森详细说明了冷战政治、官僚惰性以及幕后经济交易如何导致联邦领导层将数亿美元资金全部投向以钚为燃料的液态金属快增殖堆，而该路线在20世纪70年代对商业后处理实施核不扩散禁令后最终永久停滞。面对福岛核事故后的当代安全关切以及现代数字基础设施对巨大基荷电力的需求，索伦森认为液态氟化钍反应堆（LFTR）提供了一种安全、低压且具备抗核扩散特性的替代方案，可替代化石燃料与传统轻水堆。美国优先发展液态金属快增殖反应堆而非阿尔文·温伯格的熔盐增殖堆，主要是由于国内政治交易和地方就业创造，而非基于技术优势。 (11:40) 钚-239需要未经慢化的快中子才能超过临界增殖阈值2，而衍生自钍的铀-233则可以在更安全的热中子能谱中维持净增殖。 (2:14) 20世纪70年代末联邦政府对商业核燃料后处理的禁令破坏了快增殖堆的燃料供应，但决策者仍未重启热中子熔盐反应堆这一替代方案。 (24:23) 液态氟化钍反应堆（LFTR）结合了常压低压运行与高热力学温度，利用被动式冷冻塞排放技术从本质上防止堆芯熔毁。 (33:47)

Reading summary

Kirk Sorensen argues that the liquid fluoride thorium reactor was abandoned in the 1970s due to political patronage and institutional momentum behind plutonium fast breeders rather than technical deficiency. He contends that thorium molten-salt technology offers an intrinsically safe, high-density energy source capable of replacing polluting fossil baseload power. Nuclear Physics and the Thermal Breeding Threshold (2:14) Sorensen explains that sustaining a nuclear breeding cycle requires crossing the "Threshold of Two"—emitting strictly more than two net neutrons per neutron absorbed, after accounting for non-fission parasitic capture. While fertile Uranium-238 transmutes into Plutonium-239, Plutonium-239 absorbs slow neutrons parasitically roughly one-third of the time in a thermal spectrum, dropping below this threshold. Consequently, breeding from Uranium-238 requires an unmoderated fast-neutron spectrum, where reaction cross-sections are significantly smaller and mandate far larger fissile core inventories. In contrast, fertile Thorium-232 transmutes into Uranium-233, which suffers non-fission capture only about 10% of the time under thermal neutron bombardment. Uranium-233 successfully crosses the Threshold of Two in both thermal and fast spectrums. Because thermal-neutron cross-sections (measured in barns) are orders of magnitude larger, a thermal thorium reactor requires substantially smaller fissile inventories to achieve criticality, forming the core physical justification for Alvin Weinberg's molten-salt breeder design. Political Patronage and Weinberg’s AEC Ouster (11:40) By 1968, the liquid-metal fast breeder reactor (LMFBR) received $75 million to nearly $100 million annually in federal research appropriations, while molten-salt breeder reactor funding was virtually negligible. White House audio recordings from June 1971 reveal that President Richard Nixon directed breeder development funds to Southern California primarily to create aerospace jobs and reward political allies, including Representatives Craig Hosmer and Chet Holifield of the Joint Committee on Atomic Energy, rather than on technical merits. Weinberg, then director of Oak Ridge National Laboratory, persistently warned about the inherent safety hazards of high-pressure solid-fuel reactors and promoted low-pressure fluid-fuel systems. His opposition collided with LMFBR champion Milton Shaw and congressional leadership. In 1972, Holifield told Weinberg that if he was concerned about reactor safety, it was time to leave nuclear energy. Weinberg was ousted, and the Atomic Energy Commission ordered the shutdown of molten-salt development in January 1973. Proliferation Policies and the Forgotten Shippingport Validation (22:02) Following India’s 1974 nuclear test using diverted plutonium, proliferation concerns transformed American energy policy. Fast breeders depended fundamentally on commercial reprocessing facilities to extract plutonium from spent light-water reactor fuel to form their massive startup cores. To address proliferation risks, President Gerald Ford banned commercial fuel reprocessing in October 1976, a policy confirmed and reinforced by President Jimmy Carter in 1977. Although the ban removed the fuel cycle required for fast breeders, LMFBR research funding paradoxically peaked between 1976 and 1980 through bureaucratic inertia. Simultaneously, the Naval Reactors branch under Admiral Hyman Rickover converted Pennsylvania's Shippingport Atomic Power Station to a thorium and Uranium-233 core. Operating from 1977 to 1982, post-operation analysis proved Shippingport produced 1% more fissile fuel than it consumed, experimentally validating thermal breeding. However, following the 1979 Three Mile Island accident and the Nuclear Waste Policy Act of 1982, the United States locked into a once-through fuel cycle, leaving the proven thorium thermal cycle neglected and Oak Ridge's institutional knowledge disbanded. Concentrated Modern Energy Demands and LFTR Advantages (30:53) Examining modern energy requirements, Sorensen points to Facebook’s Arctic data center, which consumes 120 megawatts of continuous power. In comparison, a $420 million Spanish solar farm produces only 20 megawatts peak for 15 hours daily across 185 hectares—costing approximately $33 per watt and necessitating ten installations plus long-distance transmission to match the facility. Because intermittent renewables remain expensive and geographically constrained, industrial grids frequently default to baseload fossil fuels, such as 1,600-megawatt German lignite coal plants. Sorensen positions the Liquid Fluoride Thorium Reactor (LFTR) as the technical answer to this baseload problem. Molten fluoride salt operates at low atmospheric pressure while delivering high-temperature heat for thermodynamic efficiency. In emergencies, freeze plugs melt passively, draining the fluid core by gravity into subcritical cooling tanks to eliminate meltdown risks. Additionally, bred Uranium-233 contains trace Uranium-232, whose daughter isotopes emit hard 2.6 MeV gamma radiation, providing intrinsic proliferation resistance against weapons diversion. Sorensen acknowledges that realizing the liquid fluoride thorium reactor requires resolving high-temperature corrosion challenges using specialized nickel alloys like Hastelloy-N. However, he maintains that the primary obstacles are non-technical: commercial deployment requires navigating four decades of regulatory structures and institutional inertia designed strictly for high-pressure, solid-fuel light-water reactors.

精炼阅读摘要

Flibe Energy创始人Kirk Sorensen指出，钍基熔盐反应堆在物理特性上具备热中子增殖与常压高温运行的固有优势，但在20世纪70年代因冷战政治利益输送、对液态金属快中子增殖堆的技术偏向以及核不扩散政策转向而被迫下马；在当下高密度能源需求与脱碳压力下，该技术迎来了重新评估与商业化的战略机遇。核燃料物理特性与热中子增殖的天然优势 (2:14) 核反应堆的可持续增殖取决于每吸收一个中子所释放的净中子数是否超过“二的门槛”——即一个中子维持裂变链式反应，另一个中子将可育材料转化为易裂变燃料。在自然界三种主要核燃料中，铀-238转化为钚-239，钍-232转化为铀-233。Sorensen分析指出，在慢速的热中子能谱下，钚-239约有三分之一的概率会发生寄生俘获而不产生裂变，净中子产额因此跌破临界阈值，迫使基于铀-钚循环的增殖堆必须采用高能快中子能谱。然而，快中子反应截面比热中子小几个数量级，导致快堆堆芯必须装载极高浓度的易裂变材料才能维持临界。相比之下，钍裂变产生的铀-233在热中子谱下的寄生俘获率仅约10%，能够稳定跨越“二的门槛”。这意味着钍增殖堆不仅可以用热中子实现净增殖，还大幅降低了维持临界所需的初始裂变燃料装载量。橡树岭国家实验室（ORNL）时任主任Alvin Weinberg据此认定，采用热中子谱和液态氟化盐燃料的熔盐堆，能够彻底避免传统固态燃料棒在中子辐照损伤下必须反复冷却、化学后处理与机械再加工的工程瓶颈。1977年至1982年间运行的Shippingport轻水增殖堆最终实现了1%的净裂变材料增益，以工程实绩证实了钍在热中子谱下增殖的可行性。政治赞助偏向与橡树岭熔盐路线的夭折 (11:40) 尽管熔盐堆物理逻辑完备，但联邦研发预算在冷战时期压倒性地流向了液态金属快中子增殖堆（LMFBR）。历史拨款数据显示，快堆年研发预算在1968年左右即达7500万至近1亿美元，而熔盐增殖堆的预算曲线几乎可以忽略。Sorensen披露的历史白宫录音显示，理查德·尼克松总统与国会原子能联合委员会（JCAE）重要成员Craig Hosmer的闭门通话证实，白宫强推快堆的动力主要源于政治交易与地方选票，旨在将联邦能源项目倾斜给南加州的航空航天劳动力，而非基于客观的技术评估。到1972年，快堆预计研发成本已攀升至7亿美元以上，并被民主与共和两党列入国家核心纲领。与华盛顿政治集团高度绑定的技术官僚体系加速了对替代方案的打压。美国原子能委员会（AEC）反应堆开发处负责人Milton Shaw对快堆持有强硬承诺，并在1972年发布的WASH-1222评估报告中系统性贬低熔盐堆的技术前景。由于Alvin Weinberg直言不讳地指出高压轻水堆的潜在安全隐患，并倡导常压液态燃料堆以规避压力爆炸事故，JCAE领导人Chet Holifield直接要求Weinberg离开核能领域。1973年1月，AEC正式勒令橡树岭关闭熔盐堆研发项目，使美国核能探索走向了单一技术路径的封闭格局。不扩散禁令与快堆产业链的制度性瓦解 (22:02) 快中子增殖堆的商业逻辑高度依赖活跃的民用化学后处理网络，以从轻水堆乏燃料中分离出大量钚用于制造快堆初始堆芯。然而，地缘政治在1970年代发生剧烈转折。1973年石油危机促使尼克松提出雄心勃勃的“独立工程”（Project Independence），但随着危机退潮，政界紧迫感迅速消散。1974年5月，印度利用从重水研究堆中提取的钚完成核试验，在华盛顿引发了对商用后处理扩散风险的普遍恐慌。面对国内政治压力，杰拉尔德·福特总统于1976年10月突然下令禁止国内商业核燃料后处理和钚分离。吉米·卡特就职后延续了这一禁令，公开批判走向“钚社会”的危险，并削减了田纳西州Clinch River快堆示范工程的预算。随着后处理原料链被制度性切断，快堆失去了燃料来源保障，但惯性官僚系统仍在1976至1980年间向其注入创纪录的研究资金。1979年三岛峡核事故进一步重创了公众对核能的信任。至1982年里根签署《核废物政策法案》，美国彻底锁定了针对核废料的“一次通过”直接深地质处置模式。在这个过程中，决策层从未反思过熔盐堆被撤销的历史错误，橡树岭团队解散，相关技术体系逐渐湮没。现代高能耗脱碳困境与液态氟化钍堆解决方案 (30:53) Sorensen将论证延伸至现代工业体系的现实需求。以Facebook在瑞典北极圈以南建设的数据中心为例，单个园区即需120兆瓦连续供电并配置40兆瓦应急柴油机；而西班牙一座占地185公顷、耗资4.2亿美元的大型太阳能电站，每天仅能提供15小时的20兆瓦峰值电力（单位峰值成本约33美元/瓦）。可再生能源低密度、间歇性及跨洲长距离输电的经济瓶颈，导致工业界往往不得不退回到如德国1600兆瓦褐煤电厂这类廉价、稳定但重度污染的基础载荷方案。液态氟化钍堆（LFTR）构成了解决该矛盾的技术路径。在氟化物熔盐（LiF-BeF2-ThF4-UF4）介质中，冷却剂可在常压下维持高温运行，极大提升了朗肯或布雷顿循环的热转换效率并彻底消除高压蒸汽爆炸风险。在安全机制上，熔盐堆依靠堆底的冷冻塞技术，遭遇断电或异常高温时冷冻盐塞自动融化，液体燃料在重力作用下被动排放至堆底次临界储存罐实现自然对流冷却。在燃料循环与防扩散层面，熔盐体系免除了昂贵的固体燃料棒制造费用，且副产物铀-233中伴生的铀-232会释放强穿透性的2.6兆伏特伽马射线（来自其子核素铊-208），不仅极难被非法挪用于武器制造，而且易于追踪监测。 Sorensen主张，液态氟化钍堆兼具固有被动安全、极高资源利用率与防扩散特性，是替代高碳基荷电源的可行方案；但其工程落地仍须克服高温熔盐对Hastelloy-N等特殊镍基合金的强腐蚀挑战，弥合长达四十年的工程经验断代，并打破专为固体燃料轻水堆定制的现有监管准入壁垒。

Detailed notes — zh

## Background 本内容由频道 Google TechTalks 于 2011 年 12 月 22 日发布在 YouTube 平台上。视频记录了 Flibe Energy 创始人柯克·索伦森（Kirk Sorensen）于 2011 年 12 月 16 日发表的技术演讲，重点探讨钍基熔盐反应堆的技术历史、当年被叫停的政治与制度原因，以及为何当下是重启该技术路线的最佳时机。 ## TL;DR 索伦森深入剖析了钍-铀与铀-钚燃料循环在中子物理特性及反应截面上的根本差异，指出钍基熔盐堆在热中子谱下具备天然的增殖与安全优势。然而，20 世纪 70 年代尼克松政府出于南加州就业政绩与两党政治考量，全力孤注一掷液态金属快中子增殖堆（LMFBR），导致橡树岭国家实验室的熔盐堆项目惨遭下马、力主安全的阿尔文·温伯格被解职。随后印度核试验引发后处理禁令与卡特政府对“钚社会”的警惕，彻底锁死了快堆路线，而希平港反应堆的成功试验则铁证了钍增殖的可行性。面对现代数字化社会的高能耗需求、传统核电的信任危机及清洁低碳的迫切目标，索伦森呼吁破除长达 40 年的认知断层与水堆监管壁垒，重新推进具备固有被动安全与防扩散优势的液态氟化钍反应堆（LFTR）。 ## Atmosphere & style 整场演讲呈现出一种严谨硬核与沉痛反思交织的叙事基调。索伦森不仅以详实的物理截面图表清晰拆解技术底层逻辑，更通过播放尼克松时期的历史通话录音与档案，还原出科学理想在冷酷政治博弈面前被无情碾压的悲剧感。现场氛围专注而发人深省，讲述中既有对阿尔文·温伯格科学良知的敬意与历史遗憾，又饱含对现代能源困局破局之路的紧迫感与坚定信念。 ## Bulletin - [02:14](https://www.youtube.com/watch?v=bbyr7jZOllI&t=134s) 物理中子截面差异决定了铀-钚燃料循环必须依赖快中子反应堆，而钍-铀-233循环在热中子谱下即可跨越有效中子数大于2的增殖阈值，省去了对极端快中子通量的依赖。 - [10:42](https://www.youtube.com/watch?v=bbyr7jZOllI&t=642s) 1970年代美国政府将快中子增殖堆确立为唯一国家优先级，主因是尼克松与原子能联合委员会为南加州选区争夺就业与军工转岗资源，而非纯粹的科学评估，这直接导致了橡树岭熔盐堆项目的下马与温伯格被解职。 - [22:02](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1322s) 1974年印度核试验促使福特与卡特政府全面禁止商业核燃料后处理与钚分离，直接切断了快堆赖以启动的燃料链条，导致投入巨资的快堆路线彻底陷入死结。 - [27:00](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1620s) 希平港核电站在运行5年后证实热谱钍-铀循环实现了1%的净燃料增殖，实证了热谱增殖的可行性；而现代液态氟化钍反应堆（LFTR）凭借常压运行与重力自流被动安全，成为解决高能耗社会脱碳与核安全焦虑的关键路径。 ## Key takeaways - [02:14](https://www.youtube.com/watch?v=bbyr7jZOllI&t=134s) 核燃料持续增殖的核心物理条件是扣除寄生吸收后的平均有效中子产额必须大于2（“2的阈值”）。 - [04:50](https://www.youtube.com/watch?v=bbyr7jZOllI&t=290s) 钚-239在热中子谱下存在约三分之一的非裂变吸收几率，导致有效中子数跌破2，因此铀-钚循环必须在快中子谱下运行。 - [04:50](https://www.youtube.com/watch?v=bbyr7jZOllI&t=290s) 快中子反应截面比热中子反应截面小几个数量级，迫使快堆必须维持极高的燃料富集度和巨大的中子通量。 - [08:33](https://www.youtube.com/watch?v=bbyr7jZOllI&t=513s) 阿尔文·温伯格早在1969年就指出，固态增殖堆致命的瓶颈在于复杂昂贵的乏燃料后处理，而液态熔盐燃料是在线处理与高燃耗的唯一出路。 - [10:42](https://www.youtube.com/watch?v=bbyr7jZOllI&t=642s) 尼克松政府与国会原子能联合委员会出于南加州就业分配与政党竞选考量，将超过7亿美元的巨额国家预算独家倾斜给快堆，边缘化了熔盐堆研发。 - [17:07](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1027s) 由于坚决主张常压液态燃料堆的高安全性并质疑传统高压水堆的安全隐患，温伯格在遭到国会官僚斥责后于1973年被免去橡树岭国家实验室主任职务。 - [20:29](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1229s) 1973年原子能委员会正式叫停熔盐堆研发，随后国际竞争与石油危机促使美国盲目加码快堆与能源自给计划。 - [22:02](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1322s) 1974年印度核试验引发核扩散恐慌，导致福特与卡特政府叫停商业铀后处理与钚分离，抽空了快堆建立在轻水堆回收钚基础上的燃料供应逻辑。 - [27:00](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1620s) 卡特总统亲自启用的希平港钍堆实验在1982年退役检测时测得裂变燃料净增加1%，无可辩驳地证明了热中子谱下钍增殖的物理可行性。 - [29:02](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1742s) 在快堆路线因后处理被禁而彻底瘫痪后，官僚体系从未回头反思过当年砍掉熔盐堆的失误，导致相关技术团队解散并产生数十年的认知断层。 - [30:53](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1853s) 现代数字化社会对高密度基荷电力的需求（如极寒地区数据中心）使得间歇性可再生能源面临高昂的输电与占地成本，最终往往迫使社会妥协倒退回污染严重的化石能源。 - [33:47](https://www.youtube.com/watch?v=bbyr7jZOllI&t=2027s) 液态氟化钍反应堆（LFTR）采用常压高温熔盐运行，根除了传统轻水堆的高压爆炸与堆芯熔毁风险，并具备重力自流排料的固有被动安全机制。 - [33:47](https://www.youtube.com/watch?v=bbyr7jZOllI&t=2027s) 氟盐耐辐射且化学稳定性极佳，伴生的铀-232强伽马辐射赋予其天然的防核扩散属性，但商业化仍需突破高温合金抗腐蚀与水冷堆主导的监管壁垒。 ## Detailed walkthrough ### [00:00](https://www.youtube.com/watch?v=bbyr7jZOllI&t=0s) 开场介绍与阿尔文·温伯格的远见讲座主持人 Chris 介绍了演讲者 Kirk Sorensen。作为 Flibe Energy 的创始人，Kirk 长期致力于推广钍核能（Thorium Energy），并建立了活跃的社区平台 energyfromthorium.com，汇聚了全球各地的业余爱好者与专业专家，共同探讨如何设计最优化的钍反应堆。这项技术早在二战后不久就已成型，并一直发展至 1970 年代初，但随后却戛然而止，转而让位于液态金属快中子增殖反应堆（LMFBR），而快堆项目后来也同样中止。本次演讲的核心问题正是：既然这是一项如此出色的技术，为什么当年没有继续下去？随后 Kirk 登台，直言自己在几乎每次分享时都会被问到同样的问题：“Kirk, Thorium sounds like a great idea. It sounds like it's a good technology, why didn’t this happen?”（Kirk，钍听起来是个极佳的主意，技术也很棒，但为什么当年没有发生呢？）他成立 Flibe Energy 旨在研发液态氟化钍反应堆（LFTR），继承了 1950 至 1970 年代橡树岭国家实验室（Oak Ridge National Laboratory, ORNL）主任阿尔文·温伯格（Alvin Weinberg）的愿景。在温伯格的设想中，钍反应堆不仅能帮助人类摆脱化石燃料、水电及现有核电技术的束缚，还能通过海水淡化、沙漠绿化（犹如对地球进行“地球化改造”）来改变全球缺乏淡水与耕地地区的经济格局。然而，这一宏大构想在 1970 年代初被强行中止。 - 平台社区：energyfromthorium.com，长期汇集全球学者与爱好者探讨最优钍反应堆设计。 - 历史脉络：二战后起步，经历成熟研发期直至 1970 年代初被叫停。 - 终极愿景：利用廉价丰沛的钍能进行海水淡化与沙漠农业，彻底重构全球不均衡的资源与经济格局。 ### [02:14](https://www.youtube.com/watch?v=bbyr7jZOllI&t=134s) 三种核燃料的物理特性与“中子阈值” 在核能时代初期，人类面前其实有三种核裂变燃料选择： 1. **铀-235（U-235）**：天然存在的可裂变材料，可直接在反应堆中引发链式裂变。 2. **铀-238（U-238）**：天然铀的主要成分，本身不可直接裂变，必须吸收中子转化为钚-239（Pu-239）后才能使用。 3. **钍-232（Th-232）**：其储量规模类似铀-238，本身同样无法直接裂变，需吸收中子转化为铀-233（U-233）后方可作为燃料。因此，铀-238 和钍都需要消耗两个中子才能完成有效利用：一个中子用于将母核转化为可裂变核素（增殖），另一个中子用于促成该核素的裂变。为了让这一过程可持续自持（即实现核燃料增殖），裂变产生的平均中子数必须大于 2。事实上，三者裂变时释放的中子数均大于 2：铀-235 裂变释放多于 2 个中子，铀-233 裂变约释放 2.5 个中子，而钚裂变时释放的中子数接近 3 个。然而，单纯看中子释放数并不足以反映物理现实，还需要扣除寄生吸收（即吸收中子却未发生裂变）的影响。Kirk 将这一关键判定标准称为“2 的阈值”（The Threshold of Two）： - **热中子区（慢中子）**：在计入吸收概率后，钚-239 释放的有效中子数跌破了 2，无法维持增殖；只有铀-233 在热中子能谱下能够跨越“2 的阈值”。 - **快中子区（快中子）**：铀-233 与钚-239 的有效中子产额均能成功跨过“2 的阈值”。这意味着，如果选择钚燃料循环（铀-钚增殖），就必须依赖快中子反应堆；而如果选择钍燃料循环（钍-铀-233），在热中子堆或快中子堆中均能实现增殖自持。 ```mermaid flowchart TD accTitle: 核燃料增殖的中子物理阈值 accDescr: 对比铀-238转化为钚-239与钍转化为铀-233在不同能谱下的有效中子繁殖能力 subgraph PuCycle["铀-钚循环 (U-238 -> Pu-239)"] P1["钚-239 (Pu-239)"] P1 -->|"热中子 (慢)"| P2["有效中子 < 2 (无法持续增殖)"] P1 -->|"快中子 (快)"| P3["有效中子 > 2 (成功跨越阈值，必须用快堆)"] end subgraph ThCycle["钍-铀循环 (Th-232 -> U-233)"] T1["铀-233 (U-233)"] T1 -->|"热中子 (慢)"| T2["有效中子 > 2 (跨越阈值，可用热中子堆)"] T1 -->|"快中子 (快)"| T3["有效中子 > 2 (跨越阈值，可用快堆)"] end ``` ### [04:50](https://www.youtube.com/watch?v=bbyr7jZOllI&t=290s) 核反应截面与快堆的发展困境既然快中子谱能确保两种燃料都越过增殖阈值，为何不直接全盘采用快堆？Kirk 指出，物理学中存在一个巨大的阻碍——**核反应截面（Cross-Sections）**。截面是用几何面积来量化核反应发生概率的物理量，其常用单位为“靶恩”（Barn，即 $10^{-24}\text{ cm}^2$）。几乎所有核材料都有一个普遍特性：热中子反应截面远远大于快中子反应截面。以铀-233 为例，其热中子截面相当巨大，而快中子截面则微缩为一个微不可见的小圆点；钚的情况同样如此。这意味着慢中子撞击引发核反应的几率，要比快中子高出数个数量级。快堆为了弥补极小截面的劣势，必须堆积极高浓度的核燃料并维持极高的中子通量。之所以当时仍坚定考虑快堆，关键在于非裂变吸收概率（图表中的红色区域）： - **热中子区**：铀-233 吸收中子后不裂变的概率约为 10%；而钚-239 则有约三分之一（1/3）的几率只吸收中子而不裂变，这一严重浪费直接破坏了热中子增殖的可行性。 - **快中子区**：吸收后不裂变的概率急剧缩小（截面放大 500 倍观察）。快中子一旦被核素吸收，几乎必然会导致裂变。因此，为了跨越“2 的阈值”，使用钚就必须建造快中子反应堆；而钍-铀-233 既可以在热中子堆也可以在快堆中实现。但当时的决策者不愿接受技术模糊性，美国由此全面下注快中子增殖堆： - **EBR-I（实验增殖堆 1 号）**：1951 年在爱达荷州建成，利用快中子将铀转化为钚，是人类历史上第一座发电的核反应堆，最初点亮了 4 盏灯泡，最终实现数百千瓦输出。 - **EBR-II（实验增殖堆 2 号）**：更大规模的快堆原型，热功率达到 62 兆瓦。 - **恩里科·费米增殖反应堆（Enrico Fermi Nuclear Generating Station）**：位于密歇根州门罗市的商用快堆，1957 年开工，1966 年达到临界状态，但不久后堆芯便发生局部熔融事故（Meltdown），导致设备损毁并停机。 ### [08:33](https://www.youtube.com/watch?v=bbyr7jZOllI&t=513s) 温伯格的抗争与熔盐堆路线提出就在全美聚焦快中子增殖堆之时，橡树岭国家实验室的阿尔文·温伯格及其团队正全力投入熔盐反应堆（Molten-Salt Reactor, MSR）的研发。熔盐堆不在快中子谱运行，而是利用减速后的热中子，核心燃料采用钍与铀-233。在 1969 年发表于核技术期刊的一系列专业论文引言中，温伯格用极其审慎而精准的措辞阐述了他与当时主流路线的分歧。温伯格写道：“The prevailing view holds that the liquid-metal fast breeder reactor is the proper path to ubiquitous permanent energy. It is no secret that I, as well many of my colleagues at Oak Ridge, have always felt differently. When the idea of the breeder was first suggested in 1943, the rapid and the efficient recycle of the partially spent core was regarded as the main problem. Nothing that has happened in the ensuing quarter century has fundamentally changed this.”（主流观点认为液态金属快中子增殖反应堆是实现无处不在的永恒能源的正道。众所周知，我和橡树岭的许多同事一直持有不同看法。当 1943 年增殖堆的概念首次提出时，部分耗尽堆芯的高效快速后处理就被视为最核心的难题。此后 25 年间发生的一切，并未从根本上改变这一物理事实。）温伯格清醒地指出，任何固态增殖反应堆只要无法解决昂贵且极其复杂的乏燃料后处理循环，其经济性和工程可行性就无从谈起。为此，他提出了解决乏燃料困境的另一条路线：要么实现极高的燃料深度燃耗，要么从根本上大幅简化后处理环节。这正是橡树岭实验室长期致力于液态燃料反应堆的原因所在——从早期的水均匀反应堆（Aqueous Homogeneous Reactor）到后续集大成的熔盐反应堆。1969 年的这批系列论文构成了核能工程文献中最早系统阐述熔盐堆潜力的论著之一，但在当时快堆独大的政策环境下，其技术潜力并未得到主流舆论的充分重视。 - 增殖堆核心瓶颈：固态反应堆面临燃料棒包壳破损、杂质积累与高难度离线化学再处理的严峻制约。 - 橡树岭的液态方案：利用熔融氟化盐作为液体核燃料载体，在线提取裂变产物与补充新料，直接绕过复杂的固态核燃料循环困境。 ### [10:42](https://www.youtube.com/watch?v=bbyr7jZOllI&t=642s) 增殖堆经费倾斜与尼克松的政治考量通过在 Google 图书中检索到的历史数据，柯克·索伦森（Kirk Sorensen）整理了一份自 1968 年起美国政府对各类增殖反应堆研发经费的拨款对比图表。数据显示，当时美国已建成数座快中子增殖反应堆，其在 1968 年获得的研发拨款便高达 7500 万至近 1 亿美元，并在图表上呈现为一条居高不下的红色折线；与之相对，熔盐增殖堆（MSBR）的绿色拨款曲线则低到几乎无法察觉，并在后续遭遇腰斩，仅在 1975 年短暂复活后又被彻底叫停。 1971 年 6 月，理查德·尼克松（Richard Nixon）总统发表公开讲话，宣布将快中子增殖反应堆列为国家最高优先级目标。索伦森播放了一段当天尼克松与来自加利福尼亚州的联邦众议员克雷格·霍斯默（Craig Hosmer）的通话录音。在电话中，尼克松直言不讳地将核能与海水淡化项目作为向南加州倾斜就业资源的政治筹码。尼克松强调需要为航天军工行业转岗人员解决生计，并要求霍斯默在原子能联合委员会（JCAE）上不断施压争取项目落地：“现在，这件事情我们必须严格保密，但我有一点毫不手软：在这个领域只要有可能开展的活动，都必须安排在南加州。”（“Now, this is got to be something we play very close to the vest, but I'm being ruthless on one thing, any activities that we possibly can, should be placed in southern California in this field.”）索伦森指出，这通电话暴露了当时白宫决策的实质逻辑：快增殖反应堆并非完全基于科学优劣被选中，而是被尼克松、霍斯默以及联合委员会主席切特·霍利菲尔德（Chet Holifield）等加州政客视为拉动本地选区就业、换取连任选票的经济工具。技术可行性或替代方案的科学评估，在“保住南加州岗位”的政党政治诉求面前退居次席。 - 1968 年快堆年研发经费约为 7500 万至 1 亿美元。 - 熔盐增殖反应堆项目在资金曲线上几乎不可见，经历取消、1975 年短暂重启后再次被终结。 - 霍斯默在通话中对尼克松释放 1600 万美元用于铀浓缩设施升级表示感谢，称这化解了一大政治难题。 ### [14:28](https://www.youtube.com/watch?v=bbyr7jZOllI&t=868s) 汉福德演讲：“增殖堆就意味着就业” 几个月后，尼克松前往美国早期重要核能基地华盛顿州汉福德（Hanford）发表演讲。尽管台下聚集了大量拥有核工程博士学位、对反应堆物理了如指掌的顶尖专家，尼克松依然选择淡化科学原理，极力渲染增殖堆的就业拉动效应。他在演讲中自我解嘲称科学是自己读书时最差的科目，高二之后就放弃了，搞不懂复杂的增殖堆原理，但它能带来实实在在的岗位：“我知道的是这一点：我们在这里拥有实现新突破的潜力，发展和平利用的电力，而这意味着就业——不仅是这个地区的就业，也为全世界数以亿计的人带来就业和动力。”（“But what I do know is this, that here we have the potentiality of holding a new breakthrough and the development of power for peace, and that means jobs, jobs for this area but jobs and power for hundreds from millions of people all over the world.”）索伦森感慨，如果当时的国家最高领导人能够真正理解不同堆型的技术本质与优劣，美国的能源技术走向或许会完全不同。然而在政治惯性推动下，快增殖反应堆迅速确立为绝对的国家战略。尼克松不仅在国情咨文与对国会的特别咨文中多次强调，甚至在 1972 年的大选中，民主党与共和党两党的竞选纲领双双将快中子增殖堆列为国家首要优先任务。 ```mermaid flowchart TD accTitle: 快中子增殖堆在1970年代确立为国家战略的政治闭环 accDescr: 展示尼克松政府、国会加州议员集团与工业界如何通过就业分配与巨额拨款，将快堆锁定为唯一优先项目。 subgraph 政治利益共同体 Nixon["尼克松政府 (白宫决策层)"] JCAE["原子能联合委员会 (霍斯默 & 霍利菲尔德)"] Industry["核工业界 (承诺投资2亿美元)"] end subgraph 资源倾斜方向 LMFBR["液态金属快中子增殖堆 (超7亿美元研发预算)"] MSBR["熔盐反应堆 (经费边缘化直至下马)"] end Nixon -->|"交换选票与岗位"| JCAE JCAE -->|"锁定两党竞选纲领"| Nixon Industry -->|"承担超支底线兜底"| LMFBR Nixon & JCAE ==>|"集中倾斜国家预算"| LMFBR Nixon & JCAE -.->|"削减并终止研发"| MSBR ``` ### [17:07](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1027s) WASH-1222 报告与温伯格的悲剧转折到了 1972 年 9 月，国会听证会已经明确美国政府将全额兜底快堆的成本超支，其研制费用已攀升至超过 7 亿美元，而核能工业界此前也已投入了 2 亿美元。面对庞大的财务无底洞，众议员克雷格·霍斯默公开表态，即便项目未能达成成本目标，他也绝不会因此大呼小叫。巨大的经济利益让华盛顿的决策者彻底与快增殖堆深度绑定。正是在同一个月，美国原子能委员会（AEC）发布了针对阿尔文·温伯格（Alvin Weinberg）熔盐增殖堆的评估报告 WASH-1222。该报告对研发中遇到的一些工程问题极尽苛责，却选择性忽略了钍基熔盐堆在安全与经济性上的固有优势。温伯格在自传《第一核纪元》（*The First Nuclear Era*）中回忆了与反应堆研发部主任米尔顿·肖（Milton Shaw）及众议员切特·霍利菲尔德的紧张会面。米尔顿·肖深得海军上将海曼·里科弗（Hyman Rickover）雷厉风行的作风真传，独断专行且拥有国会的全力支持，将液态金属快中子增殖堆（LMFBR）作为不容置疑的唯一方向。作为压水堆（PWR）专利发明人的温伯格，在研发钍堆的过程中逐渐意识到常压运行的液体燃料熔盐堆远比高压水冷堆安全，因而持续呼吁重视反应堆安全性问题。然而，这种科学良知却触怒了急于推进快堆上马的政治官僚。在激烈的争论中，众议员切特·霍利菲尔德当面厉声斥责道：“阿尔文，如果你这么担心反应堆的安全性，那我认为也许是你离开核能界的时候了。”（“Alvin, if you're so concerned about the safety reactors, then I think it might be time for you to leave nuclear energy.”）索伦森指出，温伯格在此后不久便被解职，这一幕成为美国乃至全人类能源发展史上的巨大悲剧，彻底切断了一条极具前景的核能技术演进路径。 - 1972 年国会听证会确认快堆研发成本突破 7 亿美元，政府承诺兜底超支。 - WASH-1222 报告成为打压橡树岭国家实验室（ORNL）熔盐堆项目的官方工具。 - 熔盐堆具备低压运行的安全特征，而传统压水堆处于高压运行状态，安全裕度差异显著。 ### [20:29](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1229s) 温伯格遭解职与熔盐堆研发的终结阿尔文·温伯格（Alvin Weinberg）在橡树岭国家实验室（ORNL）的职业生涯，最终因极具权势的国会议员切特·霍利菲尔德（Chet Holifield）一句欠考虑的评价而戛然而止。1994 年温伯格在其自传中回顾这段往事时，表现得相当豁达与坦然。演讲者引用了温伯格自传中的原话：“I look back in these events, I realize that leaving Oak Ridge was the best thing that could have happened to me. My views about nuclear energy were at variance with those of the AEC congressional leadership. After all, it was I who had called nuclear energy a Faustian bargain, who continued to promote the molten-salt breeder.”（“回顾这些事件，我意识到离开橡树岭是发生在我身上最好的事情。我对核能的看法与原子能委员会及国会领导层的观点大相径庭。毕竟，正是由我将核能称为‘浮士德式的交易’，也是我一直在坚持推崇熔盐增殖堆。”）温伯格对钍基路线的不懈追求，显然是他被美国原子能委员会（AEC）免去橡树岭实验室主任职务的核心原因。当时，美国主流势力将海量资金、工业界支持和全部信心押注在快中子增殖堆（Fast Breeder Reactor）上。面对这种压倒性的利益格局，温伯格却在全力推动一条截然不同的技术路径，其遭遇打压并被终止工作也就不足为奇了。1973 年 1 月，原子能委员会正式下令橡树岭国家实验室终止熔盐堆（Molten-Salt Reactor, MSR）的研发工作。仅仅三个月后，理查德·尼克松（Richard Nixon）总统便公开重申了他对快增殖堆的全力支持，声称该堆型从铀中提取的能量是轻水堆的 30 倍，是美国核能研发的最高优先级目标。此外，1973 年 8 月法国的“凤”反应堆（Phénix）成功达到临界，国际竞争的加剧进一步助长了美国力图在快堆领域独占鳌头的狂热决心。 - **1973 年 1 月**：美国原子能委员会（AEC）正式下令橡树岭实验室终止熔盐堆研发。 - **1973 年 4 月**：尼克松重申快增殖堆为核研发最高优先级，强调其对铀的利用率是轻水堆的 30 倍。 - **1973 年 8 月**：法国“凤”快堆达到临界，加剧了美国在快堆技术上的领跑焦虑。 --- ### [22:02](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1322s) 石油危机与印度核试验带来的核不扩散震动然而在 1973 年，爆发了影响更为深远的地缘政治危机——第四次中东战争（赎罪日战争）导致欧佩克（OPEC）实施石油禁运。美国的石油供应骤减，引发了严重的社会混乱：加油站前排起望不到头的长队，民众被迫按单双号轮流加油，许多人甚至无法正常通勤，大量经济活动陷入停摆。巨大的政治经济压力迫使尼克松宣布了“独立项目”（Project Independence），旨在到 1980 年实现美国能源自给自足。该宏图包括大规模建造快增殖堆与传统核反应堆、开采新油田、新建炼油厂和煤矿等。尽管该计划在国会大力推广，但随着 1974 年 3 月石油禁运解除，推进“独立项目”的紧迫性迅速减退。更为致命的冲击发生在 1974 年：印度利用从重水堆天然铀中分离出的钚，成功引爆了核装置。这一事件彻底颠覆了美国对核能的政策取向，决策层极度担忧从核燃料后处理设施中分离出的钚会被挪用于制造核武器。尽管行业内有大量论据表明常规轻水堆排出的反应堆级钚（Reactor-grade plutonium）难以直接用于核武，但外界依旧担忧操作流程的微调可能制造出武器级钚（Weapons-grade plutonium）。整套快堆计划恰恰建立在利用轻水堆后处理所分离的钚作为初始装料的假设之上。快堆需要比热中子反应堆高得多的初始燃料装量才能启动，原因正是在于快中子谱下钚的裂变截面远小于热中子谱，一旦禁止后处理，整个快堆宏图便抽空了根基。 ```mermaid flowchart TD accTitle: 快堆燃料供应逻辑与防扩散禁令的断裂 accDescr: 流程图展示了轻水堆燃料通过后处理提供快堆初始装量，但因印度核试验引发防扩散担忧并出台后处理禁令，最终导致快堆燃料链断裂的过程。 subgraph FuelChain["原定燃料循环路径"] A["轻水堆 (LWR) 乏燃料"] --> B["核燃料后处理与钚分离"] B --> C["快增殖堆 (FBR) 初始装载"] C -.->|"需要高密度燃料填补微小裂变截面"| C end subgraph PolicyShock["地缘政治与政策剧变"] D["1974 印度核爆试验 (重水堆钚原料)"] --> E["核扩散风险担忧爆发"] E --> F["禁止商业铀后处理与钚分离 (福特/卡特政府)"] end F -->|"阻断核心原料供应"| B ``` --- ### [24:23](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1463s) 从福特到卡特：后处理禁令与快堆的政治死结 1974 年尼克松因水门事件辞职后，杰拉尔德·福特（Gerald Ford）接任总统，并重组了原子能委员会，将其拆分为核管理委员会（NRC）以及能源研究与开发署（ERDA，即后来的美国能源部 DOE）；由霍利菲尔德领导的国会原子能联合委员会也随之被废除，打乱了原有的核能权力格局。福特起初仍大力支持快堆，不仅在国情咨文等演讲中多次提及其能将铀资源寿命延长数百年，还追加了研发经费。然而在 1976 年大选前夕，面对主张彻底废除核燃料后处理的吉米·卡特（Jimmy Carter）所带来的巨大竞选压力，福特在距大选仅一周的 1976 年 10 月 28 日戏剧性地反戈，采纳了卡特的立场，宣布停止铀后处理与钚分离，并将核扩散风险列为主因。 1977 年卡特就职后，继续把这一禁令定为国家政策，并着手削减位于田纳西州橡树岭附近的克林奇河增殖堆（Clinch River Breeder Reactor）的经费。卡特直言不讳地抨击对快堆的盲目投入导致了太阳能等其他技术发展的滞后，并提出了“钚社会”（Plutonium society）这一警示性概念。他在宣布转向依靠煤炭的新能源方案时明确指出：“There's no need to enter the Plutonium age by licensing or building a fast breeder reactor such as the proposed demonstration plan at Clinch River.”（“我们完全没有必要通过批准或建造像克林奇河拟建示范堆那样的快增殖堆，来跨入这个所谓的‘钚时代’。”） - **机构重组**：福特拆分 AEC 为 NRC 与 ERDA（后来的 DOE），并废除了国会原子能联合委员会。 - **1976 年 10 月 28 日**：大选在即，福特突然宣布叫停商业铀后处理和钚分离政策，以此应对卡特的政治攻势。 - **克林奇河增殖堆受阻**：卡特上台后大幅削减该项目资金，强调绝不能步入由快堆主导的“钚时代”。 --- ### [27:00](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1620s) 希平港钍堆实验成功与快堆路线的彻底沉寂耐人寻味的是，卡特对钍能源其实有所了解。当时海曼·里科弗（Hyman Rickover）海军上将正在海军反应堆分支机构主导一项实验，将二氧化钍和二氧化铀-233 混合堆芯装填至希平港核电站（Shippingport Atomic Power Station）。正是卡特总统亲自合上电闸，启用了美国历史上首个也是唯一一个钍增殖反应堆。卡特本人曾数次表示，美国希望尝试钚以外的增殖堆路线，特别是利用铀-233 与钍的轻水增殖堆。然而，1979 年三里岛核事故的爆发彻底摧毁了公众对核电尤其是轻水堆的信任。即使后来罗纳德·里根（Ronald Reagan）上台并废除了商业后处理禁令，工业界也再无意愿建造新的后处理厂。希平港反应堆在钍-铀-233 堆芯下持续安全运行了五年，于 1982 年按计划退役检测。科学家对其乏燃料进行严格分析后，得出了一个里程碑式的结论：堆芯内的裂变燃料比初始装载量净增加了 1%。这一铁证无可辩驳地向世人证明，在热中子能谱下实现钍燃料增殖是切实可行的。由于放弃了乏燃料后处理，原定由快堆消化轻水堆钚废料的策略化为泡影，里根总统因此于 1982 年签署了《核废物政策法案》（Nuclear Waste Policy Act），确立了深地质处置路线（如后来的尤卡山处置库）。令人啼笑皆非的是，即便后处理已被叫停，美国政府在整个卡特执政时期（1976-1980 年）对快增殖堆的研发拨款依然屡创新高，形成了长达数年的政策脱节。 | 反应堆项目 | 堆芯燃料体系 | 能谱类型 | 关键验证结果 / 历史地位 | |:--- |:--- |:--- |:--- | | **希平港反应堆 (Shippingport)** | 二氧化钍 ($ThO_2$) + 二氧化铀-233 ($^{233}UO_2$) | 热中子谱 (Thermal Spectrum) | 运行 5 年后燃料净增加 1%，实证了热谱钍增殖的可行性 | | **克林奇河增殖堆 (Clinch River)** | 钚-铀混合氧化物 (MOX) | 快中子谱 (Fast Spectrum) | 因高昂成本、反核情绪及卡特政府后处理禁令而遭大幅撤资停滞 | | **法国“凤”反应堆 (Phénix)** | 钚-铀氧化物燃料 | 快中子谱 (Fast Spectrum) | 1973 年达临界，曾刺激美国在快堆研发竞赛中盲目加码 | --- ### [29:02](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1742s) 历史性反思与现代液态氟化钍反应堆（LFTR）的时代契机回顾整个历程，原子能委员会之所以押注快增殖堆，是因为钚在该能谱下的中子增殖因子能够稳稳越过“阈值 2”（$\eta > 2$），这在当时被视作毫无悬念的必赢之局；而钍在热中子谱下的富余裕量相对狭窄，存在更多理论与工程未知数。于是，政府过早且孤注一掷地偏向快堆，工业界跟投数亿美元，尼克松更是将其拍板为国家最高能源战略。这一决策直接导致了温伯格被解职与熔盐堆项目的全盘下马。当后来后处理被禁、快堆彻底失去立足之地时，华盛顿的官僚机构却从未真正回头反思过当年的战略失误。演讲者深有感触地指出：“In all of my studies, I have not been able to find any indication that, that ever took place, that there was a true revisiting of that decision to shut down and a rethinking.”（“在我的所有研究中，从未发现任何迹象表明，当年有人真正重新审视过关闭熔盐堆的决定并进行过反思。”）橡树岭原有的顶尖技术团队最终分崩离析，宝贵的工程经验也在随后的数十年中几乎被社会彻底遗忘。站在 2011 年的时代节点，重新提出液态氟化钍反应堆（Liquid Fluoride Thorium Reactor, LFTR）——这一熔盐堆的现代演化形态——恰逢其时。当今人类社会正迫切需要以极低的经济成本获取海量能源，同时必须将对地球生态的破坏降至最低。面对全球气候变化、冰川消融、海平面上升和极端气象频发的残酷挑战，人类亟需在短时间内大幅减少二氧化碳排放。然而与此同时，公众对传统核电的信任危机依然深重，亟待一种本质安全、防扩散且经济高效的全新清洁能源方案来破局。 - **确定性偏差**：AEC 当年认为钚快堆越过“阈值 2”是确定无疑的买卖，而钍存在不确定性，导致过早锁死技术路线。 - **团队解体与知识断层**：熔盐堆被撤项后，橡树岭核心团队散落各处，相关技术被边缘化并封存数十年。 - **时代需求转换**：2011 年对 LFTR 的再发掘，核心驱动力在于廉价能源供应、碳减排目标以及解决传统核电公众信任危机之间的多重现实交织。 ### [30:53](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1853s) 福岛事故的影响与现代高能耗社会的供电困境福岛第一核电站（Fukushima Daiichi）事故虽然没有造成直接的人员死亡，但其广泛的媒体报道与舆论基调，彻底动摇了公众对核电安全性的信心。公众质疑的核心主要集中在轻水堆上——高压流体与堆芯熔毁的潜在威胁始终难以完全消除。与此同时，传统的化石能源替代方案在开采、加工、燃烧及燃料运输过程中，都会对大气和生态造成巨大破坏，而长途输电线路的架设也成本高昂。即便全面布局分散式的可再生能源，跨区域输电网络的建设壁垒同样极为严峻。 ```mermaid flowchart TD accTitle: 现代高能耗需求与能源供应对比 accDescr: 对比高能耗数据中心与太阳能、煤电供应的现实差距与环境代价。 subgraph Demand["高密度电力需求 (瑞典)"] FB["Facebook 数据中心 持续消耗 120 MW 造价 7.6 亿美元"] end subgraph CleanSupply["间歇性分散清洁能源 (西班牙)"] Solar["大型太阳能电站 占地 185 公顷 峰值 20 MW (日照15小时) 需 10 座以上 + 跨洲输电线路"] end subgraph Reality["现实妥协方案 (德国)"] Coal["褐煤发电厂 持续输出 1600 MW 可供 13 座数据中心 带来严重环境破坏"] end Solar -.->|"供电不稳定且昂贵"| FB Coal ==>|"廉价可靠但污染严重"| FB ``` Kirk Sorensen 列举了一个极具代表性的现代数字化用电案例：Facebook 在瑞典北极圈以南仅 100 英里处建立了一座造价 7.6 亿美元的数据中心。该设施需要持续消耗 120 兆瓦的水电，并配备了 14 台备用柴油发电机以提供 40 兆瓦的应急电力。相比之下，位于西班牙的一座全球顶尖大型太阳能电站占地达 185 公顷，造价 4.2 亿美元，峰值功率仅有 20 兆瓦，且每天最多发电 15 小时，折合每瓦成本高达约 33 美元，比常规输电建设成本高出 6 到 7 倍。如果试图用这种分散、间歇的太阳能来维持瑞典寒冷地区数据中心的无间断运转，不仅至少需要 10 座以上的同规模光伏电站，还得铺设跨越整个欧洲大陆的特高压输电线路。这在现实中极难推行，世界最终往往不得不转向像德国褐煤电站那样的集中式高密度能源。这类煤电厂单座就能稳定输出 1600 兆瓦电能，足以驱动 13 座上述数据中心，但代价是对生态环境的持续肆虐。Kirk Sorensen 总结道：“大多数人、地球上的绝大多数人口都无法负担没有补贴的替代能源，它实在太贵了；他们最终会转向廉价、可靠但肮脏的能源。” - **Facebook 瑞典数据中心参数**：耗资 7.6 亿美元，稳定功耗 120 MW，配备 14 台备用柴油机提供 40 MW 备用电力。 - **西班牙大型太阳能电站参数**：占地 185 公顷，耗资 4.2 亿美元，峰值出力 20 MW，每日有效发电仅约 15 小时，单位造价约 33 美元/瓦。 - **德国现代化褐煤电厂参数**：单厂持续供电能力达 1600 MW，发电量相当于 13 座大型数据中心所需负荷。 --- ### [33:47](https://www.youtube.com/watch?v=bbyr7jZOllI&t=2027s) 熔盐反应堆的核心技术优势与发展壁垒面对兼顾环境与能源密度的双重挑战，Kirk Sorensen 指出储量丰富且天然低廉的钍（Thorium）才是破局的关键，而搭载钍的机器则是技术核心。熔盐之所以是四种潜在反应堆冷却剂中唯一的理想介质，是因为它能在高温条件下维持极低的常压运行，从物理根源上消除了高压爆裂和堆芯熔毁的危险。更关键的是，液体燃料具备独特的固有被动安全性——在突发紧急状况下，燃料盐可以通过自熔性重力自流阀直接排入底部的应急储存罐，实现无需人工干预的被动安全冷却，这在任何固体燃料反应堆中都是无法做到的。 ```mermaid flowchart LR accTitle: 液态氟化钍反应堆 (LFTR) 核心优势与主要挑战 accDescr: 展示 LFTR 在安全高效方面的技术优势与面临的工程及监管挑战。 subgraph Advantages["技术优势"] A1["常压低压运行 无高压破裂爆炸风险"] A2["被动重力排料 紧急状态液体自流冷却"] A3["氟化物化学匹配良好 抗辐射损伤 / 极高燃耗"] A4["铀-232伴生 防核扩散与武器挪用"] end subgraph Challenges["工程与制度挑战"] C1["高温熔盐对金属材料的腐蚀"] C2["长达 40 年的技术停滞与认知断层"] C3["现行法规完全基于铀水冷堆标准"] end Advantages -.->|"需攻克壁垒以实现商业化"| Challenges ``` 在化学与物理性能方面，氟化盐与“铀-钍燃料循环”堪称绝配。氟盐化学性质极为稳定，完全不受辐射损伤，支持堆芯与包层之间的在线连续循环处理，从而实现几乎无限制的燃料深度燃耗，省去了复杂的固体燃料元件制造费用。此外，副产物中的铀-232伴随强伽马射线辐射，让铀-233极难被挪用用于制造核武器，且在紧急状态下极易通过贫化降档处理，具备极强的防核扩散属性。Kirk Sorensen 强调：“我们相信天然、廉价且储量丰富的钍就是答案。这种物质具有足够的能量密度和可靠性，能提供世界所需的能量，但让它发挥作用的机器才是关键。” 然而，液态氟化钍反应堆（LFTR）的前行道路依然面临诸多技术和制度壁垒。熔盐在极高温度下对常规结构金属具有较强的腐蚀性，必须研发专门的抗腐蚀耐高温合金；高温运行本身既是热效率的保障，也是工程材料的重大挑战。但最大的阻碍并非工程本身，而是这项技术在过去 40 年中几乎处于停滞状态，主流核能界对其认知严重断层。由于现有的核能安全监管体系完全是围绕传统铀燃料水冷堆建立的，要推进钍基熔盐堆的全面商业落地，必须进行深度的公众认知与行业监管教育。演讲最后，Kirk Sorensen 表示 Flibe Energy 致力于成为全球液态氟化钍反应堆设计、研发与制造的领军企业。 - **固有热工优势**：高温低压工况，大幅提升热机循环的热力学转化效率，免除大型高压安全壳的建造成本。 - **燃料经济性与物理安全性**：无固态燃料颗粒加工与更换成本；紧急情况下燃料盐自动排入被动冷却排料罐。 - **主要瓶颈与挑战**：特种合金耐腐蚀需求、40 年的技术研发断层，以及完全由水冷堆垄断制定的监管审批环境。 ## Notable quotes > [33:47](https://www.youtube.com/watch?v=bbyr7jZOllI&t=2027s) 我们相信天然、廉价且储量丰富的钍就是答案。这种物质具有足够的能量密度和可靠性，能提供世界所需的能量，但让它发挥作用的机器才是关键。 — Kirk Sorensen > [30:53](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1853s) 大多数人、地球上的绝大多数人口都无法负担没有补贴的替代能源，它实在太贵了；他们最终会转向廉价、可靠但肮脏的能源。 — Kirk Sorensen > [17:07](https://www.youtube.com/watch?v=bbyr7jZOllI&t=1027s) 阿尔文，如果你这么担心反应堆的安全性，那我认为也许是你离开核能界的时候了。 — 切特·霍利菲尔德 ## Mentioned Kirk Sorensen, Chris, Flibe Energy, energyfromthorium.com, 阿尔文·温伯格, 橡树岭国家实验室, 理查德·尼克松, 克雷格·霍斯默, 原子能联合委员会, 切特·霍利菲尔德, 米尔顿·肖, 海曼·里科弗, 杰拉尔德·福特, 吉米·卡特, 罗纳德·里根, 美国原子能委员会, 美国核管理委员会, 美国能源研究与开发署, 美国能源部, 欧佩克, Google, Facebook, EBR-I, EBR-II, 恩里科·费米增殖反应堆, 克林奇河增殖堆, 希平港核电站, 凤反应堆, 福岛第一核电站, WASH-1222 报告, 《第一核纪元》, 《核废物政策法案》, 独立项目, 尤卡山处置库 ## Video description Google Tech Talk December 16, 2011 Presented by Kirk Sorensen [Source](https://www.youtube.com/watch?v=bbyr7jZOllI)

Source quotes

[33:47] Kirk Sorensen: 我们相信天然、廉价且储量丰富的钍就是答案。这种物质具有足够的能量密度和可靠性，能提供世界所需的能量，但让它发挥作用的机器才是关键。 [30:53] Kirk Sorensen: 大多数人、地球上的绝大多数人口都无法负担没有补贴的替代能源，它实在太贵了；他们最终会转向廉价、可靠但肮脏的能源。 [17:07] 切特·霍利菲尔德: 阿尔文，如果你这么担心反应堆的安全性，那我认为也许是你离开核能界的时候了。

Source quotes

[7:20] Alvin Weinberg: The successful breeder will be the one that can deal with the spent fuel or the spent core most rationally either by achieving extremely long burn up or by greatly simplifying the entire recycle step. [30:53] Kirk Sorensen: If we try to use expensive intermittent and alternative energy, it's not going to be the answer. [24:23] Jimmy Carter: There's no need to enter the Plutonium age by licensing or building a fast breeder reactor such as the proposed demonstration plan at Clinch River.

Original transcript

[0:00] >> For our presentation today from Kirk Sorensen, the founder of Flibe Energy. [0:03] Kirk has been a promoter of energy from Thorium for a long time as [INDISTINCT] energyfromthorium.com [0:08] where pretty big community of amateurs and experts from around the world that had been [0:14] contributing to the community effort to define what would be the optimal Thorium reactor, [0:19] nuclear reactor which generates electricity from Thorium. [0:23] This is a technology that's been around for a long time since, shortly after World War [0:28] Two. [0:29] It was matured well up until early 1970s and then, and then kind of suddenly ended in favor [0:34] of the liquid-metal fast breeder reactor which then also ended. [0:38] And Kirk will give us a talk today and explain kind of what went wrong, why it stopped, why [0:44] it--how is this been done. [0:45] You know, if it's such a great idea, why aren’t we doing it? [0:48] And their actions have very good reasons for that and maybe other reasons are cost and [0:52] then, maybe we should start doing it again. [0:54] So, please have Kirk Sorensen. [0:56] >> SORENSEN: Thank you very much, Chris. [0:57] I'm very glad to be here at Google today and given another Tech-talk. [1:00] I always enjoy coming and been a part of these things. [1:03] The question that I'm going to try to answer today is one that I'm often asked as I give [1:08] presentations on Thorium. [1:09] In fact, I'm almost always asked this question which is, "Kirk, Thorium sounds like a great [1:13] idea. [1:14] It sounds like it's a good technology, why didn’t this happen?" [1:18] We are Flibe Energy a new company to develop liquid fluoride Thorium reactor technology. [1:23] We're following the vision of Alvin Weinberg. [1:26] He was the director of Oak Ridge National Lab from the 50s to the 1970s and he had a [1:31] vision of how we could use Thorium to advance beyond the current constrains of our society [1:37] in terms of fossil fuels, hydro power and existing nuclear technology. [1:42] One of the amazing parts about his vision was how this could transform not only the [1:46] US economy but many other places in the world. [1:48] Some of which don’t have the resources that we have in terms of fresh water or arable [1:53] land. [1:54] This is a vision he had of how Thorium reactors could be used to desalinate water, grow crops [1:59] in desert areas and to some of us like caught terraforming the earth, but to really truly [2:04] change the economic balance of the world. [2:09] Weinberg's vision on the other hand, was brought to an end in the early 1970s and that is really [2:13] the subject of the talk today. [2:14] There really were three options for nuclear energy at the dawn of the nuclear era. [2:19] There was Uranium-235 which was fissile form of Uranium. [2:23] This was the form of Uranium, they could actually be utilized directly in a nuclear reactor. [2:28] Most of the Uranium was the Uranium-238. [2:31] This had to be transformed into another nuclear fuel called Plutonium before it could be used. [2:36] And then there was Thorium and in a similar magnitude reining 238, it also had to be transformed [2:42] into another nuclear fuel, Uranium-233 before it could use in a reactor. [2:47] There were some significant differences though between these three fuels. [2:50] As I mentioned, Uranium-235 could be used directly. [2:54] The other two had to be transformed and that meant, they needed two neutrons to be consumed, [2:58] one to transform them and one to fission them. [3:00] And in order for this to be a sustainable process, you have to know what will they emit [3:05] more than two neutrons when they fission. [3:07] And the answer was, "Yes, they did." [3:09] In fact, all three of them emitted more than two neutrons when they fission. [3:13] Here was Uranium-235, Uranium-233 admitted about two and a half neutrons per fission [3:19] and Plutonium with fission with almost three neutrons per fission. [3:23] So, it would emit the most neutrons when it fissions. [3:25] So, the first answer was yes. [3:27] All three of the fuels gave off enough neutrons to sustain their consumption of reactor. [3:32] But there was more to the story, this is a busy graph and I apologize in advance for [3:37] it. [3:38] But it tells the story of much of our nuclear history. [3:40] And what it shows is, Plutonium doesn’t emit enough neutrons when it isn’t being [3:45] fission by fast neutrons in order to continue the conversion of future Uranium into Plutonium [3:52] to continue its breeding. [3:53] It has to be fissioned by fast neutrons in order to do this. [3:57] On the other hand, Thorium and Uranium-233 produce enough neutrons in both thermal and [4:03] fast fission to continue the utilization of that fuel. [4:07] I call it the Threshold of Two, and it's not just about how many neutrons they emit, but [4:12] how many neutrons they emit even accounting for absorption. [4:16] Because they don’t always fission every single time they're hit by a neutron. [4:20] Uranium-233 and Plutonium-239 of those two in thermal neutrons, only Uranium-233 crosses [4:28] the Threshold of Two. [4:29] In fast fission on the other hand, both Uranium-233 and Plutonium-239 crossed the Threshold of [4:36] Two. [4:37] So, it would seem, what we just want a fast reactor. [4:40] We don’t want a reactor that uses slow down thermal neutrons, we want a fast reactor because--then [4:45] we will great confidence that we will be able to sustain the consumption of nuclear fuel. [4:50] Well, there's a powerful disincentive to doing it this way and it has to do with what are [4:57] called, Cross-Sections. [4:58] These are mathematical way of describing how likely it is that a nuclear reaction will [5:03] proceed and they the form of areas, quite literally in area someone's called "a barn" [5:09] which is, 10 to the minus 24 square centimeters. [5:12] This is a really, really, really small unit to variat. [5:15] But this is the unit that nuclear engineers used to describe how probable a nuclear reaction [5:21] is. [5:22] This is the cross-section of Uranium-233 to a thermal neutron. [5:26] By comparison, this very, very small circle right here is the cross-section of Uranium [5:31] 233 to a fast neutron. [5:33] So, it's not hard to see which one is more likely to have a fission reaction. [5:39] A thermal neutron is far more likely to cause the fission reaction than a fast neutron. [5:44] So, the advantage now seems to be for the thermal reactors. [5:48] This is a general feature of almost all nuclear materials that their cross-sections are much [5:53] larger to thermal neutrons than they are to fast neutrons. [5:56] Here we see the cross-section of Plutonium. [5:59] It's huge in the thermal spectrum and it's very, very small in the fast spectrum. [6:04] And that means that Plutonium is much more likely to have a nuclear reaction to a slow [6:10] down neutron than to a fast neutron. [6:12] So again, why consider a fast reactor? [6:15] Well, it's because--look at these red regions. [6:19] Those regions indicate the probability that the neutron will be absorbed but not cause [6:24] a fission, that it will simply just be absorbed. [6:27] You can see that, that probability is about 10% for Uranium-233 in the thermal. [6:31] But if we were to magnify that cross-section, significantly by factor of 500, you could [6:38] see that, that probability becomes much smaller in the fast spectrum. [6:43] A fast neutron if it is absorbed almost always will cause a fission. [6:47] This is significant for Uranium-233 but it's much more significant for Plutonium 239. [6:53] It will absorb a neutron about one-third of the time and not cause a fission. [6:57] But in the fast spectrum, it will almost always cause a fission. [7:01] So, to make sure that we cross that Threshold of Two, it was necessary to build fast reactors [7:08] that would use Plutonium. [7:10] On the other hand, it was conceivable that you could build thermal or fast reactors that [7:16] would use Uranium-233. [7:17] This uncertainty was not particularly appearing at the time. [7:21] They wanted to move out in directions that they felt very confident it. [7:24] So, the United States began to pursue a fast breeder reactor. [7:29] In 1951, they build the experimental breeder reactor one in Idaho. [7:34] This was a fast breeder reactor. [7:35] This was a reactor that was going to not slow down neutrons but use fast neutrons to convert [7:40] Uranium into Plutonium and to breed from it. [7:43] This was actually the first reactor to generate some power. [7:46] It lit four little light bulbs and ultimately generated, I believe several hundred kilowatts [7:50] of power. [7:51] But it shows how early the United States was moving out on the fast breeder reactor. [7:56] It was followed by the experimental breed reactor number two, which was also a fast [8:01] breeder reactor much larger this time. [8:04] It made 62 megawatts of thermal power. [8:07] Industry got excited about the potential for making breeder reactors. [8:12] This was actually a commercial reactor, The Enrico Fermi Breeder Reactor in Monroe Michigan. [8:18] They began working on this reactor in 1957 and it achieved criticality in 1966. [8:25] But shortly after it achieved criticality, they had a melt down at the Enrico Fermi Reactor [8:30] where the reactor was damaged and shut down. [8:33] At this time, Alvin Weinberg and his colleagues at the Oak Ridge National Labs were working [8:39] on Molten-salt Reactors. [8:40] These were reactors that didn’t operate in the fast spectrum. [8:44] They operate to slow down neutrons and they predominantly were interested in using Thorium [8:49] and Uranium-233. [8:51] Weinberg wrote an introduction to a series of papers that were published in a nuclear [8:55] journal in 1969. [8:57] And these are some of the words that he used and I've always found it very interesting [9:02] how careful and measured he was with his utilization of language. [9:07] Because he knew that most of the effort of the country was on the fast breeder reactor [9:11] and very little in comparison was on the Molten-Salt Reactor. [9:15] And he said, "The prevailing view holds that the liquid-metal fast breeder reactor is the [9:20] proper path to ubiquitous permanent energy. [9:23] It is no secret that I, as well many of my colleagues at Oak Ridge, have always felt [9:28] differently. [9:29] When the idea of the breeder was first suggested in 1943, the rapid and the efficient recycle [9:35] of the partially spec core was regarded as the main problem. [9:39] Nothing that has happened in the ensuing quarter century has fundamentally changed this." [9:44] So, Weinberg begins to lay out the scenario that physics hasn't changed and unless you [9:50] can rapidly reprocess nuclear fuel, you won't be able to realize the benefits of the breeder [9:55] reactor. [9:56] He then goes on to offer an alternative to the prevailing view. [10:00] The successful breeder will be the one that can deal with the spent fuel or the spent [10:05] core most rationally either by achieving extremely long burn up or by greatly simplifying the [10:11] entire recycle step. [10:13] We at Oak Ridge, have always been intrigued by this latter possibility. [10:17] It explains our long commitment to liquid fuel reactors, first, the Aqueous homogenous [10:21] and now the Molten-salt. [10:22] So, he presented a different scenario, how they could use fluid field reactors to achieve [10:28] the overall goal of the efficient utilization of nuclear fuel. [10:33] And the series of papers that followed in this were some of the first discussions in [10:37] the nuclear literature about the potential of the Molten-salt reactor. [10:40] It was not well-known. [10:42] The moneys that had been appropriated in order to research the different breeder reactor [10:47] types are listed in this graph and I found this graph, thanks to a book that had been [10:51] scanned into Google books. [10:52] Thanks. [10:53] So, project started by my good friend, Chris Eucare here, so I greatly appreciate--this [10:56] is one of the many things I'm sure people have done with your work. [10:59] Numbers are one thing, so I took it and threw it in a spreadsheet and made a nice graph. [11:04] The red line shows the expenditures on the fast breeder reactor, and this graph only [11:08] begin to 1968. [11:09] At that point, the United States had already built several fast breeder reactors. [11:15] We're looking at 75 to nearly a hundred million dollars in 1968. [11:20] It's very hard to see the green line for the Molten-salt breeder reactor technology, it's [11:24] extremely low and then ultimately, it was cancelled and briefly resurrected in 1975 [11:29] and then cancelled again. [11:30] So, on a scale of the appropriations that were made to the fast breeder reactor, you've [11:35] just about can't see the appropriations that were made to the Molten-salt breeder reactor. [11:40] In June of 1971, President Richard Nixon made a speech where he talked about the need for [11:49] the fast breeder reactor. [11:50] He put the United States on record that this would be a top national goal. [11:55] Now, we don't have any video from the speech he gave that day. [11:58] But later on in that day, he called Representative Craig Hosmer from California to tell him about [12:04] the speech about the breeder reactor. [12:05] >> Yeah. [12:06] >> Calling for Craig Hosmer, sir. [12:08] Ready? [12:09] >> HOSMER: Oh. [12:10] >> NIXON: Okay. [12:11] >> HOSMER: Mister President? [12:12] >> NIXON: Since you missed our meeting when we had--on a breeder reactor, you know... [12:16] >> HOSMER: Okay. [12:17] >> NIXON: ...I wanted you to know that we sent a message today, Craig but then I just [12:19] told Zigler that--I told Zigler to tell the press that there's a by part [INDISTINCT] [12:23] that you and [INDISTINCT] >> HOSMER: All right. [12:26] >> NIXON: ...had been bugged me about it. [12:27] The one thing I wanted to tell you too is that, I--Holified was there last night at [12:31] the [INDISTINCT] Club thing, and I--and I have told the people around here--now, this [12:37] is got to be something we play very close to the vest, but I'm being ruthless on one [12:41] thing, any activities that we possibly can, should be placed in southern California in [12:46] this field. [12:47] And also, in the saline water field. [12:49] >> HOSMER: Correct. [12:50] >> NIXON: You know, we need the jobs. [12:52] We need to sum up those air passed workers. [12:54] Now, we got some--we're going to do a couple of new things on water for example, and I [12:58] have decided to throw one big plant in southern California. [13:00] I mean, you know, a big one of these implementing it, if you know what I mean, is... [13:05] >> HOSMER: Right, right. [13:06] >> NIXON: ...it's just a question how big the plant is. [13:08] But in this energy field, I told Dr. David and of course, Seaborg and the rest that we [13:13] do it. [13:14] So, on the committee, everytime you have a chance, needle them, say, "Where is this going [13:18] to be?" [13:19] Let's push the California thing. [13:20] Can you do that? [13:21] >> HOSMER: Incidentally, Mister President... [13:22] >> NIXON: Yeah. [13:23] >> HOSMER: ...I am so delighted that you released $16 million on the improvement if the enriching [13:24] complex. [13:25] I bet that handles the bad... [13:26] >> NIXON: Right. [13:27] >> HOSMER: ...political problem for us. [13:28] >> NIXON: Right. [13:29] Good, good. [13:30] Well, they told me you were interested in it, and I said, "Well, if Hosmer is for it, [13:35] I'm for it." [13:36] >> SORENSEN: All right. [13:38] Let's pause there. [13:39] You can tell just a little bit from listening to Nixon's words that, the fast breeder reactor [13:45] was viewed by him and probably some others in administration as something that they could [13:49] use to economic advantage for the people of southern California to get it. [13:54] Nixon was from California, Hosman was from southern California, Holifield, Chet Holified [13:58] who ran the--joined the committee on atomic energy was also from California. [14:03] And I think some of the phrases in this--in this phone call is very interesting. [14:06] I'm going to be ruthless on this. [14:08] We've got to play this very close to the vest. [14:10] It's about jobs, if you're for it, and I'm for it. [14:13] It doesn't lead me to believe that the President was seriously considering alternatives to [14:19] the fast breeder reactor. [14:20] Another past that could’ve been taken. [14:22] It was focused on what can we do right now to get jobs back home to the--the folks are [14:27] going to support us in re-election. [14:28] Well a few months later, Nixon was at Hanford, Washington which is the side of many of our [14:34] nations earliest nuclear energy facilities. [14:38] And he was also giving a talk on the significance of the breeder reactor. [14:42] And again, note the economic potential that he puts in front of people during his talk. [14:48] >> NIXON: That is why I made an announcement on June the 4th, one that didn't get of course [14:52] the enormous publicity of the announcement of the journey to China, one that didn't get [14:57] the publicity of my announcement of the economic policy to deal with the problems of inflation [15:02] and unemployment in this country. [15:04] But one which in terms of the future of the country maybe in long term, long range terms [15:11] even more important in some respects and that is, at the United States was going to go forward [15:18] in building a breeder reactor. [15:21] Now, don't ask me what a breeder reactor is, ask Dr. Slazenger, but don't tell, I'm not [15:25] to tell you because unless you're one of those PHDs, you won't understand it either. [15:29] But what I do know is this, that here we have the potentiality of holding a new breakthrough [15:38] and the development of power for peace, and that means jobs, jobs for this area but jobs [15:44] and power for hundreds from millions of people all over the world. [15:49] >> SORENSEN: Jobs, job is what it was all about. [15:52] And this area that Nixon was talking to in Hanford, Washington, this was a very well-educated [15:57] area. [15:58] A lot of the people in the back in there probably had PHDs in nuclear engineering and knew exactly [16:02] what a breeder reactor was. [16:04] But Nixon was emphasizing the economic benefits to them of his announcement that there was [16:09] going to be a breeder reactor. [16:11] >> NIXON: All of this business about breeder reactors and nuclear energy and the stuff [16:15] is over my--that was one of my poorest subjects, Science and I got through it, but I had to [16:20] work too hard. [16:21] I gave it up when I was about a sophomore. [16:23] >> SORENSEN: Well, maybe it might have benefited our country a little more if Nixon had been [16:27] able to ascertain the different values of different types of a breeder reactors and [16:31] why one might have an advantage over another. [16:34] But nevertheless, the US was now firmly on the course of making the breeder reactor, [16:39] a national priority. [16:41] Nixon emphasized it in his State of the Union Speech. [16:44] He then emphasized it in another message to congress, the democratic and republic in party [16:48] platforms in 1972 both included the fast breeder reactor as a national priority. [16:54] Now, this is about the time when Weinberg's story with the Molten-salt reactor begins [16:59] to intersect this much larger story of the breeder reactor and the congressional support [17:05] behind it as well as the presidential support. [17:07] Testimony given in September of 1972, they noted that the US government would be expected [17:12] to cover cost overruns on the breeder reactor and the development cost would go over $700,000,000. [17:19] At this point, industry had already committed $200,000,000 then your dollars to the breeder [17:25] reactor effort. [17:26] Representative Craig Hosmer, who was the fellow on the phone call that we heard earlier, said [17:31] that "If cost targets were missed, I for one don't intend to scream and holler about it." [17:35] It's not hard to see that they could see great economic benefits occurring to their area [17:41] of the country if the breeder reactor program was to go forward. [17:45] In that same month, the atomic energy commission issued WASH 1222, which was an evaluation [17:51] of Weinberg's Molten-salt breeder reactor. [17:54] It was highly critical of several technological issues that had been encountered during the [18:00] development of that idea, more importantly though, it almost completely ignored the safety [18:06] and economic improvements possible through the use of the Molten-salt breeder reactor [18:11] technology. [18:13] Weinberg himself had a meeting which Chet Holified and Milton Shaw of the Atomic energy [18:18] commission in 1972. [18:19] We don't know exactly when this meeting took place. [18:22] Our only record of it is contained in Weinberg's book, his autobiography, The First Nuclear. [18:27] Here's what he said, "I found myself increasingly at odd with the reactor to the vision of the [18:32] Atomic energy commission. [18:33] The director at the time was Milton Shaw. [18:35] Milt was cut from the Rickover cloth, he had a singleness of purpose and was prepared to [18:40] bend the rules and regulations in achievement of his goal." [18:43] Why would he feel this pressure if he has the president and these congressional folks [18:47] pushing for the fast breeder reactor? [18:49] "At the time, he became director, the atomic energy commission had made the liquid-metal [18:53] fast breeder reactor, the primary goal of it's reactor program. [18:57] Milt tackled the LMFBR project with Rickoverian dedication: woe unto any who stood in his [19:02] way. [19:03] This caused problems for me since I was still espousing the Molten-salt breeder." [19:07] Milt was like a bull, he enjoyed congressional confidence so his position in the AEC was [19:11] unassailable. [19:12] And it was clear that he had little confidence in me or Oak Ridge. [19:16] After all, we were pushing Molten-salt not the fast breeder, more than that, we were [19:20] being troublesome over the question of reactor safety. [19:23] And that was another aspect that was getting Weinberg into trouble. [19:26] He had invented the pressurized light water reactor that formed the backbone of the reactor [19:32] technologies that were being developed in the country at that time. [19:35] Here's a picture of some of the pressurized water reactors. [19:38] His work on the Thorium reactor led him to believe that a significantly higher level [19:43] of safety was possible. [19:44] And this--in large part was because the Thorium reactor operated low pressures whereas, water-cooled [19:50] reactors operated the high pressures. [19:52] So, he was beginning to bring these issues up in support of the Thorium reactor, but [19:58] it didn't have that effect. [20:00] Congressman Chet Hollifield was clearly exasperated with me and he finally blurted out, "Alvin, [20:04] if you're so concerned about the safety reactors, then I think it might be time for you to leave [20:09] nuclear energy." [20:11] But I was speechless, but it was apparent to me that my style, my attitude and my perception [20:15] of future were no longer in tune with the powers within the AEC. [20:19] And I think this was a very sad moment in the history of our country and probably in [20:24] the history of the world because an entire direction of potential development was being [20:29] ended at that moment by a not well thought out comment by Congressman Holifield, who [20:36] was very powerful. [20:38] Weinberg looked at this fairly philosophically when he wrote his autobiography in 1994. [20:41] And He said, "I look back in these events, I realize that leaving Oak Ridge was the best [20:46] thing that could have happened to me. [20:47] My views about nuclear energy were at variance with those of the AEC congressional leadership. [20:52] After all, it was I who had called nuclear energy a Faustian bargain, who continued to [20:56] promote the molten-salt breeder. [20:58] So, Weinberg's pursuit of Thorium appears to have had a great deal to do with why he [21:04] was fired from his position at Oak Ridge in the atomic energy commission. [21:08] And it's not hard to see when you stack up the forces that weren't supportive of the [21:13] fast breeder and that effort, the money, the industrial backing, the confidence they had [21:20] and here is Weinberg trying to push something different, why they would attempt to truncate [21:25] his work. [21:26] The [INDISTINCT] that was in January of 1973, Oak Ridge was directed by the atomic energy [21:31] commission to terminate the development of the molten-salt reactor. [21:34] April of that year, Nixon went into reiterate his commitment to the fast breeder, saying [21:38] it would extract 30 times more energy from Uranium than light water reactors and it was [21:42] highest priority target for nuclear resear and development. [21:46] We weren't the only ones pursuing the fast breeder reactor. [21:49] In August 1973, the Phenix reactor in France achieved critically. [21:54] So, we had real competition in this area and I think it had something to do with the zeal [21:59] the United States felt to become preeminent in this field. [22:02] But then something else happened in 1973 that was far more significant. [22:06] The Yom Kippur war started, it led to the OPEC oil Embargo. [22:10] Suddenly, the United States, their supply of oil was cut back tremendously. [22:15] There were long lines, gas stations, people were having to alternate days when they could [22:20] buy gas, people were--somebody's not able to get to work, enormous amount of economic [22:26] activity which truncated. [22:28] Nixon felt great pressure so, he announced project independence which was a plan to make [22:32] the United States energy independent by 1980. [22:35] This involved building many fast breeder reactors, many conventional reactors, new oil drilling, [22:41] new refineries, new coalmines, all kinds of things to make the United States independent [22:47] in energy supply. [22:48] He promoted these in talks before congress but then in March of 1974, the oil Embargo [22:53] ended and pressure reduced to implement project independence. [22:58] But something else happened that was very significant in 1974. [23:02] India detonated a nuclear weapon that had been built from Plutonium separated from natural [23:07] Uranium and a heavy water reactor. [23:09] This was a very significant event in the history of how the United States approached nuclear [23:14] power because they became quite fearful, the Plutonium that could be separated from Uranium [23:20] in reprocessing facilities would be able to be used in a nuclear weapon. [23:25] And there are many arguments why that is not feasible in conventional light water nuclear [23:31] reactors, but there are also other arguments on how changes on how you would put fuel through [23:35] a reactor could lead to, so called Weapons Grade Plutonium, rather than what we call, [23:41] Reactor Grade Plutonium which is not suitable for nuclear weapons. [23:44] The entire fast breeder program was partially built on the assumption that separated Plutonium [23:50] would be available from the light water reactors that we had already built. [23:54] If we were able to take that Plutonium out, we would be able to start these fast breeder [23:57] reactors because they required significantly more nuclear fuel to turn them on than a light [24:03] water reactor did. [24:04] And that had to do with those relative cross-sections I showed, how big the Plutonium cross-section [24:10] was in the thermal reactor versus how small it was in the fast reactor. [24:14] That's why it takes so much more fuel to start a fast breeder reactor for the same electrical [24:20] power rating than a thermal reactor. [24:23] Nixon resigned in 1974 and Gerald Ford became the President. [24:26] He put some changes in place for the atomic energy commission, splitting it into two new [24:31] divisions, the nuclear regulatory commission and the energy research and development administration [24:35] which would go on to become the DOE. [24:37] The joint congressional committee in atomic energy lead by Chet Holifield was abolished, [24:42] the balance of power which changed when Ford came in, in 1974 and made these changes to [24:48] the AEC and to the congressional committee. [24:51] But Ford still supported the fast breeder reactor. [24:54] He mentioned it in several of his speeches including in State of the Union Address. [24:58] He increased funding for RND for the fast breeder reactor. [25:02] And he highlighted how the fast breeder reactor could be used to extend Uranium resources [25:06] for centuries. [25:07] As the 1976 election approached though, it was very close between Jimmy Carter and Gerald [25:13] Ford. [25:14] Jimmy Carter wanted Uranium reprocessing to be abolished. [25:19] He did not want it to take place. [25:21] Only about a week before the election, on October 28th, 1976, Ford took Carter's position. [25:27] He said, "We are not going to reprocess Uranium anymore. [25:31] We're not going to separate Plutonium," and he highlighted the risk of proliferation as [25:35] one of the main reasons why he was making this decision. [25:39] But it's almost certain that pressure from Carter and an attempt to improve his potential [25:45] to win the 1976s election had to have something to do with it. [25:49] At that time, the proposal was to build another fast breeder reactor. [25:53] This time in Tennessee, very close to Oak Ridge on the Clinch River, so this was the [25:57] proposal that was before the nation as Jimmy Carter became the President in 1977. [26:03] And Carter was not a supporter of this fast breeder reactor. [26:07] He considered that the fast breeder reactor and its concentration had something to do [26:13] with the lack of technology development and solar energy. [26:17] He blamed the focus that had been on the fast breeder reactor. [26:20] He called our society a Plutonium society that would use the fast breeder reactor. [26:25] In April, he reiterated Ford's ban on reprocessing. [26:29] So, not too much of a surprise, Ford had basically assumed Carter's position, Carter's says, [26:34] "Yes, we will continue that as National Policy." [26:37] He also calls for a cut back and funding for the Clinch River breeder reactor. [26:42] However, he announced a new energy plan, focused less on petroleum and more on coal. [26:46] He said, "There's no need to enter the Plutonium age by licensing or building a fast breeder [26:51] reactor such as the proposed demonstration plan at Clinch River." [26:54] And again, he blamed the emphasis on the breeder reactor for slow progress made in the progress [26:58] of solar power. [27:00] Surprisingly, Carter knew a thing or two about Thorium. [27:03] And the reason he did is because at this time, Admiral Rickover was working with his neighbor [27:09] reactors branch to load a Thorium Dioxide Uranium-233 Dioxide core into the shipping [27:15] port reactor. [27:16] Carter was able to turn the switch that turned the first and only Thorium breeder reactor [27:22] in US history on. [27:23] Several times he mentioned how--we wanted to try other approaches to breeder reactors [27:28] than Plutonium, specifically light water breeder reactors using Uranium. [27:33] But then, a meltdown happened a Three Mile Island, public confidence in nuclear energy [27:37] in particular the light water reactor really went down. [27:41] Even after Ronald Reagan was elected and lifted the ban on commercial reprocessing, no reprocessing [27:46] plans were built. [27:47] In 1982, the shipping port reactor which had been running for five years at this point [27:51] on the Thorium, Uranium-233 core were shut down. [27:55] And when they examined the fuel, they found that there was 1% more fuel in the reactor [28:00] than there was when they started. [28:02] This proved finally a Thorium breeder reactor was possible in a thermal spectrum. [28:07] It had actually been done. [28:08] It wasn't a Thorium molten-salt reactor, but it was a true Thorium breeder reactor. [28:14] Another consequence of the decision not to reprocess nuclear fuel meant that we had to [28:19] have a new strategy for the long-term disposal of Plutonium. [28:23] Previously had been assumed that Plutonium from light water reactors would be sent to [28:27] fast breeder reactors but without that, we need to know what to do. [28:31] And so President Reagan sign in the Nuclear Waste Policy Act, which continues to be the [28:35] law of the land till this day, and led to things like the [INDISTINCT] repository. [28:39] The funding that went into the fast breeder reactor surprisingly peaked even after the [28:46] United States had made the decision not to continue with reprocessing. [28:49] And even under the Carter years, from 1976 to 1980, you can see funding levels for the [28:53] fast breeder were very high. [28:55] So, this was a reactor type that dominated the long range planning of the United States [29:01] for many, many years. [29:02] The atomic energy commission saw Plutonium as a sure bet in the fast breeder. [29:07] It could cross the Threshold of Two. [29:09] There wasn't uncertainty there. [29:10] There was a degree of uncertainty with Thorium. [29:13] They invested early and heavily in the fast breeder reactor, despite failures and meltdowns, [29:19] and industry got involved with hundreds of millions of dollars of investment. [29:22] In 1971 Nixon, made this the US strategy, how are we going to go forward? [29:28] It was going to be based around the fast breeder, and shortly thereafter, Weinberg was fired [29:32] and the molten-salt reactor program was cancelled. [29:34] Before it cancelled the fuel processing program and Carter extended that ban, without fuel [29:39] reprocessing, the fast breeder was not a viable candidate anymore. [29:42] And nobody as far as we know in DC ever revisited the question of, "Was it a mistake to cancel [29:50] the molten-salt reactor effort?" [29:52] Should we have gone back and said, "You know, now that we're not going to do the fast breeder, [29:55] maybe we should've done the molten-salt breeder reactor." [29:58] In all of my studies, I have not been able to find any indication that, that ever took [30:03] place, that there was a true revisiting of that decision to shut down and a rethinking. [30:09] The team that worked on this at Oak Ridge disbanded and dispersed. [30:12] And over the decades that fall the notch was totally forgotten. [30:15] So now, here we are in 2011 asking, "Why is now the right time for the Liquid Fluoride [30:21] Thorium Reactor, which is the modern form of the Thorium molten-salt reactor originally [30:26] proposed?" [30:27] We know that we need much more energy at much lower prices. [30:30] And we have to do this with a much lower impact on the earth's environment. [30:35] We know that we're facing severe challenges from global climate change, melting of glaciers, [30:41] rising sea levels, changing weather patterns. [30:43] We need to reduce the amount of carbon dioxide we're putting into the atmosphere dramatically. [30:48] There's tremendous uncertainty amongst the public about nuclear power because of the [30:53] events of Akushima Daichi, even though no one was killed there. [30:57] The coverage and the tone that it took has made people question the safety of nuclear [31:01] power, primarily the light water reactor to be able to have a different technology that [31:07] doesn't have some of the risks of operating high pressure fluids and reactors that have [31:13] the capability to have meltdowns. [31:15] It's significant. [31:16] Our alternatives in the form of fossil fuel caused tremendous environmental degradation, [31:20] not just in mining and processing, but also to our atmosphere, transporting these fuels. [31:27] It's not cheap to build electrical power transmission lines either. [31:30] So, even if we wanted to build renewable energy sources dispersed in a wide variety of places, [31:35] they would face challenges in order to get transmission lines built from here to there. [31:39] To give you an idea of just some of the things we do in our high-tech online society today, [31:44] this is a picture of a data center for Facebook that has been built just a hundred miles south [31:49] of the Arctic Circle in Sweden. [31:51] It consumes a hundred and twenty megawatts of hydro power, has 14 backup diesel generators [31:57] to provide 40 megawatts of emergency power. [32:01] It costs $760,000,000. [32:03] This is one of the largest solar installations in the world. [32:06] It's sited on a hundred and eighty-five hectares of land. [32:09] It provides 20 megawatts of peak energy for 15 hours a day at $420,000,000, or about $33 [32:16] a watt. [32:17] That's six to seven times what it cost to put other power transmission in. [32:22] So, this is in Spain and the data center is in Sweden. [32:25] So, here is an example of a customer that has a dense power demand that wants continuous [32:30] power, no interruptions and it's in frozen Sweden and here is a diffused power supply [32:35] in Spain. [32:36] So, to run this building of those solar power systems, we'll need at least six, but we need [32:43] more because these plants can only provide power for 15 hours a day. [32:46] So, we'll need probably 10 or more of these sites to run one of these data centers. [32:51] Plus, we'll need intercontinental transmission lines to get power from a place like Spain, [32:56] that's nice and sunny, to a place like Sweden that's frozen. [32:59] Is this what's going to happen? [33:00] Probably not, probably what will happen is something more like this, where a dense power [33:05] supply in the form of coal. [33:07] This is the prettiest coal plant I've ever seen in my life. [33:09] This is in Germany. [33:11] But it provides 1600 megawatts of continuous power by burning lignite coal. [33:16] Look at that, we could run 13 of those data centers with one of these coal plants. [33:22] Sounds great right? [33:23] Well unless you're the environment. [33:25] If we try to use expensive intermittent and alternative energy, it's not going to be the [33:29] answer. [33:30] Most populations, most people on earth can't afford unsubsidized alternative energy. [33:36] It's just too expensive. [33:37] What they'll go towards is cheap, reliable, dirty energy. [33:42] That's not a viable answer for the world either. [33:44] But it's the one that will be taken because most people don't have alternatives. [33:47] We believe natural, inexpensive, and abundant Thorium is the answer. [33:52] This is the material that is dense enough and reliable enough to provide the energy [33:56] that the world needs, but the machine to make it work is the key. [34:00] Why molten-salt? [34:02] Because molten-salt is the only one of the four potential coolants in the reactor that [34:06] can run at both high temperature and low pressure. [34:09] It also has a remarkable feature because of the properties of molten-salt. [34:13] In the event of an emergency, the fuel could be drained into a passively safe, passively [34:18] cool configuration. [34:20] This is something that you can't do with a solid-fueled reactor. [34:23] Finally, the advantages of the molten-salt reactor are significant, inherent passive [34:27] safety through having fluid fuel and operating at low pressure. [34:31] You can operate at high temperatures, which means you can get high thermodynamic efficiencies. [34:35] Your fuel preparation costs are very low and there's no fuel fabrication cost. [34:40] Fluorides also tried to be an excellent chemistry match with Uranium Thorium Fuel Cycle. [34:44] They're chemically stable and they're impervious to radiation damage. [34:48] That enables us to achieve unlimited fuel burn up and continuous recycling of the material [34:53] from core to blanket. [34:55] Uranium-233 is highly unsuitable for weapons diversion because of contamination with Uranium-232. [35:01] And it's easy to down blend it in an emergency. [35:03] Now, we do have challenges. [35:05] These salts could be aggressive towards most metal construction materials. [35:08] It requires special materials to avoid being corroded by the salt. [35:14] High temperature operation is also both a blessing and a challenge. [35:19] But I think the fact that the technology base is largely stagnated for 40 years is our single [35:23] greatest challenge towards going forward, and also the unknown nature of this within [35:29] the nuclear community. [35:30] It's very different than what we do today with water cooled Uranium fueled reactors. [35:34] They are the basis for today's regulatory environment. [35:37] And so, there will be a great deal of education needed for this technology to go forward. [35:42] But I think it has great potential because of these attributes. [35:45] And five energy aspires to be the world leader in the design, development, and manufacture [35:49] of these liquid fluoride Thorium reactors. [35:51] Thank you very much.