How We Know It Works
The thorium fuel cycle has been known to science from the start of the atomic era, and reactor designs associated with that cycle have been around since the 1950s. The first successful use of thorium came from the Department of Energy’s MSRE experiment, a 1960’s-era project from the Oak Ridge National Laboratory working from prior research to build a molten salt reactor for aircraft propulsion.[104] The 7.4 Megawatt reactor went online in 1965 and worked successfully for four years until the experiment was cancelled in 1969 in favor of Light Water Reactors.[105] Light Water Reactors eventually became the national standard largely because they could produce both energy and weapons-grade radioactive isotopes.[106]
While that unfortunate result isn’t particularly surprising, the results of the MSRE experiment nonetheless conclusively showed that the reactor concept was viable,[107] as have other tests since. The MSRE experiment confirmed predictions and expectations, showing the safety, efficiency and heat transfer potential for LFTRs was present using 1965-era capabilities. Several other countries and companies have since made progress on LFTR technology. Notable high-profile projects include:
China: The Chinese government has invested $3.3 Billion into molten salt reactors in Gansu province under the name “Thorium-Breeding Molten Salt Reactor (TMSR).”[108] These reactors are being built underground, and are intended to generate up to 100 megawatts of power. Their reactor models heavily leverage cogenerative design, using excess energy to power other resource-producing systems including fresh water, hydrogen and hydrocarbon fuels.[109]
Although a large focus of this project is electricity for civilian usage, the Chinese government hopes to apply the results of this project to military applications like drones and future fast aircraft carriers.[111] As reactor miniaturization would be required for placement within something as small as a drone or warship, such an advance would present significant implications for NATO states in both civilian and military sectors – making a matching investment in LFTR technology all the more pressing. As of this writing, the Chinese program intends to have a functional reactor prototype by 2025 with large-scale commercialization by the early 2030’s.[112]
The Netherlands: The Dutch NRG (Nuclear Research and Consultancy Group) is one of the leading European nuclear service providers. They have constructed a prototype Molten Salt Reactor that began fluoride salt irradiation on August 10th, 2018.[113] Instead of turning a live reactor “critical” for sustained civilian power, the NRG intends to conduct a series of experiments (referred to as SALIENT) to reinforce the validity of thorium energy and use the experiments as templates for future LFTR development.[114]
Unique among other thorium R&D efforts outside of G8 states is the NRG’s installation in Petten, which has all of the decontamination, cleaning, salt production, radiation shielding and fine element analysis equipment to build a nuclear reactor in-house.[115] As a semi-private venture, the NRG can now compete with state-level actors to fine-tune the necessary manufacturing requirements to achieve LFTR viability.
India: A nuclear power since the 1950’s, India is no stranger to the promise, challenges, and risks inherent to atomic energy. Yet among members of the “nuclear club,” India is unique in that it has the largest thorium reserves of any sovereign nation – some 11.5 million metric tons.[116] This has led India to accelerate research and development on thorium-powered molten salt reactors as a part of its three-stage nuclear program.[117]
India’s latest effort is the Kalpakkam prototype fast breeder reactor, designed to generate 500 megawatts of electricity. The Kalpakkam prototype is expected to reach criticality by the early 2020s.[118]
Explaining the benefits of the reactor model to the Times of India, the Director General of the International Atomic Energy Agency noted that “fast reactors can help extract up to 70 percent more energy than traditional reactors and are safer than traditional reactors while reducing long-lived radioactive waste by several fold.” It’s worth noting for our purposes that while fast breeder reactors are akin to LFTRs in both theory and function, and present promising results even in initial prototype stages, the designs have had stability issues in the past and present varied engineering challenges to long-term stability.[119]
For this reason, India has been running a forerunner reactor to the prototype they’re building in Kalpakkam under the Fast-Breeder Test Reactor program. This smaller reactor has had its own technical challenges, yet has reliably produced impressive amounts of energy even while operating at significantly less than total capacity.[120] In doing so, it has provided Indian nuclear scientists with the data needed to complete the larger Kalpakkam reactor – which itself can be used as a stepping stone to further advancement in breeder reactors that leverage the thorium fuel cycle. The third stage of India’s nuclear program is designed to use thorium exclusively.[121]
Russia: while India has nearly completed their prototype fast breeder reactor, Russia has successfully deployed the technology since the early 1980s at the Beloyarsk Nuclear Power Station.[122] The station currently operates two fast breeder reactors – the only two in the world that are currently operational – respectively generating 600 and 885 megawatts each.[123] However, unlike Indian variants, these Russian fast breeder reactors are fueled by enriched uranium, due to plentiful Russian reserves and the security “benefit” of uranium’s dual support of civilian energy and nuclear armament.
Things are changing, however, as Russia is currently developing a high-temperature breeder reactor fueled by thorium, which, like China’s variant, is expected to divert waste heat energy to desalinate seawater and extract hydrogen.[124] This Russian reactor will also be partially fueled by weapons-grade waste material – paying homage to the ability of molten salt reactors to safety generate electricity as a byproduct of armament reduction initiatives.[125] Professor Sergey Bedenko from the School of Nuclear Science & Engineering at Tomsk Polytechnic University and a co-author of a paper[126] on the project had this to say on the benefits of plutonium-processing:
This project also has the benefit of state backing. As of 2016, President Vladimir Putin has directed Russia’s state energy institutes, Rosatom and Kurchatov, to deliver a proposal on how to leverage thorium for next-generation reactors while improving thorium procurement through rare-earth metal extraction.[127] As reactor technology improves with future research and development, we may see more sophisticated Russian LFTRs that can be manufactured at scale.
Germany: As of this writing, Germany has transitioned from nuclear power to a more renewable-focused approach in response to anti-nuclear political pressure.[128] The results have been mixed at best, and Germany still relies heavily on coal to complement the intermittency and unreliability of using renewables for baseload power.[129] Germany once had functional thorium reactors that operated at high efficiencies and output. Although the design wasn’t a Molten Salt Reactor, their THTR-300 high-temperature thorium reactor worked successfully between 1985 and 1989,[130] but was decommissioned in favor of light-water reactors. Despite its higher costs and unique engineering requirements, the experimental THTR-300 reactor proved thorium’s viability as a fuel and presented a rich supply of test data for future high-temperature reactors.
The United States: as the world’s first nuclear power, spearheading the discovery of both fission and fusion, the United States has extensive experience with atomic energy. Nearly all nuclear engineering today is derived from American designs – including reactors fueled by thorium.
Yet most of these reactors were designed with the intent of providing an ample supply of weapons-grade nuclear material alongside a civilian power program, and the United States remains the only nation in the world to deploy a nuclear weapon in an armed conflict. For these reasons, alongside debates over how to dispose of the nuclear waste associated with Pressurized Water Reactors, atomic energy in America faces significant political resistance – even though it generated 60% of our emissions-free power in 2016.[131]
The political mood is changing, however. 2016 saw the first new American nuclear reactor to come online in decades,[132] and that reactor now generates enough energy to power 650,000 homes.[133] Myriad companies, from startups to long-established nuclear engineering firms, are now exploring advances in thorium reactor technology. Several are even investing in “microreactors,” scaled-down modular reactor designs that can be mass-produced on assembly lines. Although some would still use uranium-235, the mass-produced approach is still important for several reasons:
First, it leverages one of the attributes that makes America the world’s wealthiest economy: its ability to build sophisticated systems on a large scale. When it comes to mass-producing cutting-edge technology with minimal room for error, America’s manufacturing prowess shines brightest. This gives the United States perhaps the best advantage when mass-manufacturing modular reactors on assembly lines to a single standard.
Second, the advances made in miniaturizing reactor technology – even if still fueled by uranium-235 – can be extended to miniaturizing LFTR technology in the future, lowering costs, barriers to entry, and barriers to scale.
Third, microreactors can be built small enough to deliver via train, ship, or even truck or aircraft. That enables them to be transported and deployed effectively anywhere – a key goal of Scarcity Zero.
Several companies are proving to be pioneers in this future frontier of nuclear energy, both within and outside of thorium:
- Westinghouse’s eVinci’s microreactor design is factory built, fueled and assembled. It’s also small enough to transport on a truck, and boasts a 0.06 acre footprint with less than 30 days onsite installation.[134] It can match the energy output of up to 380 acres of wind turbines and 79 acres of solar panels.[135] And at zero emissions, the equivalent energy output with diesel would produce 230 million pounds of CO2. It was partially envisioned to power military bases and research stations in frigid climates where wind turbines freeze, sun is scarce and diesel fuel is the only viable source of energy. Westinghouse’s current designs – planned for release in 2024 – estimate constant operation for upwards of ten years without refueling.[136]
- Corvallis, Oregon-based NuScale Power has its own microreactor designs. Their Small Modular Reactor is designed to provide scalable power generation up to 720 megawatts. While based on the light-water model, their modular design eliminates two-thirds of the internal parts of traditional Pressurized Water Reactors and also incorporates a passive auto-shutdown that doesn’t require external power, additional water or operator action. These distinctions present critical advantages over previous reactor designs, not only in terms of safety but also because they avoid the need for the redundant and expensive containment systems.
At a deployment area of 15x82 feet, the containment vessel and reactor core are roughly 5% of the size of a traditional nuclear power plant[137] - small enough to be delivered by rail, barge or truck. To date, the company has secured more than $300 million in funding from the Department of Energy.138/cite] They plan to construct a 12-module Small Modular Reactor plant at the Idaho National Laboratory by 2026,[139] that would provide up to 720 megawatts of emissions-free power.[140]
- General Atomics is a defense contractor specializing in aerospace and nuclear engineering. As a former subsidiary of General Dynamics, it’s been on the front lines of nuclear advancement since its commercialization, with a proven track record of building reliable high-performing reactors. Their latest reactor concept is billed as an “Energy Multiplier Module,” which is a series of modular microreactors that can be deployed together as a unit and buried below ground.[141]
Image Source: General AtomicsGeneral Atomics reactor designs mimic the benefits of LFTRs in function – breeding, automatic operation for up to 30 years, passive non-mechanical safety measures, the ability to consume both nuclear waste and weapons-grade material as fuel and a high-temperature loop that can be used for supplemental resource production. Although the design is still in concept stages, they have received more than $60 million in funding thus far from the Department of Energy, and continue to join other companies domestically and abroad in developing Small Modular Reactors.[142]
- Terrestrial Energy is a joint Canadian-U.S. startup specializing in thorium-fueled molten salt reactors. It has been working alongside the United States Department of Energy and Oak Ridge National Laboratory to bring smaller-scale LFTRs to market.[143] Larger than a microreactor yet significantly smaller than a traditional nuclear power plant, their patented Integral Molten Salt Reactor (IMSR) is modular in design and scalable from 80 to 600 Megawatts on 17 acres or less.[144] As with any LFTR, Terrestrial Energy’s design includes secondary and tertiary heat loops for supplemental resource production. The company is expecting to start their first reactors by the 2020’s with larger-scale commercial viability thereafter.[145]
As designed, each of these modular reactors can be assembled in groups to meet the output of base load power.
The litany of investments in LFTR and other small modular reactor technologies are made because we know these technologies will work, as prototype after prototype has proven it so. We know reactor miniaturization works because we’ve designed and built miniature reactors after thousands of iterations of modeling and tests. We know that standardization and modularity in the design of advanced systems gives way to greater scalability and flexibility in deployment, because we’ve seen these concepts produce this exact effect in every other industry they’ve been employed.
The developed world isn’t investing many billions of dollars into next-generation nuclear technology on a whim, nor would it do so if the science was in doubt. It’s perhaps for this reason why market growth in microreactor technology is increasing at an annual rate of 19%[146] - the investment follows the data, and the data supports the investment.