ThorCon – Demonstrated Molten Salt Tech Packaged With Modern Construction Techniques

The dearth of real innovation and focused direction from the established companies in the US nuclear industry in the face of rapidly expanding demand for clean energy solutions has stimulated the formation of a number of start-up companies. The leaders of these companies have backgrounds that have taught them to ask “Why not?” when faced with the standard nuclear industry response of “The NRC will never let you_____” (fill in the blank).

ThorCon is a packaged nuclear power plant concept from Martingale, Inc. that is designed to wring capital costs out of nuclear plant construction. The company visionaries have recognized that the biggest hurdles to building new actinide-fueled reactors are the initial capital investment along with the excessive required construction lead time.

Instead of complaining that “the market” does not reward carefully crafted works of industrial art designed to last for sixty to one hundred years with lucrative paybacks delayed for three or four decades after final investment decisions, the ThorCon design team started with the notion that product designers must create offerings that satisfy market demands.

Today’s energy market rewards financial flexibility, predictable construction schedules, reasonably low investment, affordable operating costs, low or no emissions, and readily implemented upgrade paths. If the offered solution is one that uses actinide fission, customers will also want to clearly understand provisions for handling process leftovers, liabilities, accident prevention, consequence mitigation and regulatory barriers.

The ThorCon conceptual design has several features that will be familiar to regular Atomic Insights readers. They are similar to the choices that Terrestrial Energy has made. Both design teams point back to the Molten Salt Reactor Experiment as a demonstration that molten salt reactor technology works and addresses many of the economic obstacles inherent in conventional light water reactors.

They both have chosen to design reactor systems that are maintained by replacement instead of being designed with expected component lifetimes measured in large fractions of a century.

ThorCon’s reactor modules (referred to be the company as the Can) are low pressure, simple systems manufactured with low cost, commodity materials. Two of the four gas-tight, fission product barriers are included in the Can. Each Can will operate for about four years. After operation they will be allowed to cool for four years and then will be shipped to a centralized facility for decontamination, inspection, and refurbishment.

Both ThorCon and Terrestrial Energy has chosen to locate most of their nuclear systems underground. For ThorCon, the top of the silo will be 29 meters underground, leading to a need to excavate a 50 meter deep hole.

Correction: Terrestrial Energy’s design is “at grade,” not underground. As is the case for any building, there will be a foundation that extends below grade.

Aside: I don’t like the idea of building nuclear plants deep underground. Digging deep holes costs substantially more than is generally estimated by people who have not built major underground projects and it adds unexpected maintenance costs. Building underground also adds site specific requirements that will hamper the ability of suppliers to mass produce identical units.

One additional reason that I am skeptical about underground siting is that the major proponent of the concept was Edward Teller, a theoretical physicist whose memoirs brag about his lack of practical engineering skills and experience. Teller was also the first chairman of the committee that initially saddled the power reactor industry with the almost impossibly expensive requirement of perfect safety. End Aside.

There are significant differences between ThorCon and Terrestrial Energy in other aspects of the design and development plans, with each team building on different core competencies.

Jack Devanney is the principal engineering designer for ThorCon. He has several decades worth of experience in modern large ship manufacturing with a deep understanding of complete project economics. He has led teams that produced high quality products for demanding customers that operate in some of the world’s harshest environments, yet he learned how to satisfy their demands for effective cost and schedule controls.

The block construction techniques that Jack plans to incorporate from the ship building industry are not conceptually different from the modular construction concepts being incorporated in both large (AP1000) and small (NuScale, mPower, Holtec, Westinghouse) light water reactors. The main difference might turn out to be his team’s experience in having successfully implemented blocks on large projects already.

The ThorCon team also includes people with financial savvy, exceptional software skills, education, marketing, and nuclear engineering.

Unlike Terrestrial Energy, ThorCon has not yet decided where it will license and demonstrate its design. It seems unlikely that ThorCon will choose to operate in the US, but there are strengths available here that should be considered.

  • There are US shipyards that have experience in modular construction. They might be too costly when operating under Navy rules, but it’s possible that they could apply their skills differently for a different type of customer.
  • There are several locations — Idaho, Hanford, and Savannah River — that are ideally suited for demonstration plant siting. There are political challenges associated with each of those sites, but there are also political opportunities.
  • One aspect of US basing is the presence of eager, trainable work forces who already have substantial nuclear experience.
  • There are political leaders who have recognized that pushing innovative nuclear energy projects off-shore is bad for business here in the US.
  • There is still a lot of work to be done to turn this recognition into a supportive development environment, but the US has experienced leaders from other industries that can attest to the fact that this is a pretty good place to do business.

Add one more ‘T’ word to your list of companies to watch.

(Here’s my current list of nuclear plant design companies with a significant US presence worth watching – Areva, Flibe, GE-Hitachi, Holtec, mPower, NuScale, TerraPower, Terrestrial Energy, ThorCon, Transatomic Power, Westinghouse. Some of those names are worth watching for negative announcements. I expect you to let me know who I’ve slighted by failing to include them in the list.)

Update (January 6, 2015 08:20 am):

Martingale issued the following press release:

Martingale reveals a bold approach to solving the global issues of poverty, pollution, energy security, and climate. The ThorCon liquid-fuel nuclear reactor design is detailed at

ThorCon is a complete system of power generation modules, interchange maintenance, and liquid fuel service that produces energy cheaper than coal. Principal engineer Jack Devanney led a four-year skunkworks project that has created a new kind of nuclear power plant, integrating proven technologies with breakthrough approaches to manufacturing and licensing. Production can start by 2020. Today Martingale is publishing its design for cheap, reliable, CO2-free electricity at

Former MIT professor Devanney’s background in shipbuilding created respect for low-cost, high-precision, block-unit manufacturing at Korean shipyards. He saw how such prefabricated blocks could enable production of enough nuclear power plants to make a global difference, a hundred a year.

Author Robert Hargraves writes that selling so many power plants requires clear, simple economics, cheaper than coal. Coal is today’s energy choice of developing nations, now planning to build over 1400 gigawatt-size coal power plants to enable their economic development.

Lawrence Livermore Lab veteran nuclear scientist Ralph Moir says that today’s nuclear power industry is wedded to expensive solid-fuel nuclear reactors, even though the simplicity of liquid fuels was demonstrated at Oak Ridge National Laboratory. Moir and Devanney modernized that design for mass production. ThorCon uses uranium and thorium fuel dissolved in molten salt to create a power plant that makes electricity cheaper than coal.

Stanford engineering alums Chris Uhlik and Lars Jorgensen contributed to the design of passive safety functions that operate without mechanical or electronic controls, even with no power. The reactor is 30 meters underground. Overheating drains the fuel salt from the reactor. There are four barriers between the fuel salt and the atmosphere. ThorCon is walk-away safe.

Taking another lesson from Oak Ridge, Martingale advocates a return to staged testing of physical prototypes for new nuclear reactor designs. This made the US the world standard for nuclear designs in the 1960s. Martingale supports adoption of the same license-by-test model that has enabled US leadership in aviation and drug discovery.

Martingale is designing ThorCon in the US while targeting its first installations in forward-looking countries that support technology-neutral nuclear regulations and see the benefits of the license-by-test process. ThorCon opens up a practically limitless supply of low-cost, reliable, carbon-free power by 2020.

Media Contact
David Devanney
(772) 285-2210

End Update.

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