When Will We Have a Working Molten Salt Reactor?

Back in October of 2015, we did a write up on 6 Nuclear Energy Companies Building Molten Salt Reactors, evaluating new strides being made towards safe nuclear power. The Molten Salt Reactor (MSR), which is projected to be safer, cleaner, and cheaper than traditional nuclear reactors, could be the next bit step in energy tech that we’ve been waiting for. The article has generated a fair amount of interest, so we thought we’d put together a comprehensive list of all startups working on this technology and try to guesstimate if/when we should see a working molten salt reactor. 

Frankly, as investors, we always get a bit sick of waiting for technologies that are moonshot. Nonetheless, the benefits mankind would reap from such a clean energy source mean that we need to check in every so often. The good news is that, in addition to the six companies we covered in 2015, there are at least four more pursuing the advancement of MSR technology. The bad news is that we’re still at least a decade away from using molten salt reactors to provide good clean energy. At the rate we’re installing solar, in 10 years this technology might not even be economically viable. Let’s take a look at the progress of the original six startups we profiled, then get into a few promising MSR developers that were brought to our attention by one of our lovely readers. 

Founded in 2013, Terrestrial Energy went all-in on their “Integral Molten Salt Reactor” (IMSR), which has targeted remote communities and industrial operations with their smaller, modular design. So far they’ve taken in $15.3 million in funding from undisclosed investors and just last month, notified the U.S. Nuclear Regulatory Commission of plans to license their IMSR in the United States. Though they still have to work through pre-application, design certification, and construction permit processes, Terrestrial’s CEO, Simon Irish, has publicly announced that 2017 will be the year that they move forward with the regulatory actions needed to bring their IMSR to market. Stay tuned for a live product in the 2020s which should look something like this:

Founded in 2008, TerraPower has given birth to the “traveling wave reactor” (TWR), which uses depleted uranium to simplify the nuclear fuel cycle. After almost 10 years of research and development, TerraPower is now taking the TWR to the engineering phase, planning to enter construction within the next five years. TerraPower, along with Southern Company (an Atlanta-based utility), was recently awarded $40 million from the Department of Energy to further their efforts. The Company was founded and funded by Bill Gates for an undisclosed amount. We’re pretty sure that funding isn’t going to be an issue here.

Founded in 2012, Moltex broke the conventional MSR mold by pursuing the development of what they call the “Stable Salt Reactor,” which uses molten salt fuel held in static fuel tubes, as opposed to the traditional MSR ‘pumped circulation’ design. In September of last year, Bloomberg interviewed founder Ian Scott and he stated that the Stable Salt Reactor is still in the works, and will be rolled out fast enough to “help prevent catastrophic climate change”. He also said that they’re looking for $30 million to make that happen. Their last news release in September of 2016 talked about press coverage they were receiving but what they really need is funding to make it happen.


Founded just recently in 2015, Elysium Industries has joined the fleet of MSR developers with their own fresh ideas in tow. Co-Founder Matthew Hayes says that other companies are just dusting off old technology, but Elysium is different. “Our team is taking into account all the recent scientific advancements and coming up with an original concept.” Elysium has already filed quite a few patents on the tech that has been spawned from this original concept. Elysium says that they’ll have a working prototype in the next five to seven years, and will be actively manufacturing in eight to 10 years. With an ambitious timeline like that, Elysium may be worth keeping an eye on. With more than 70 employees working on the project, it would seem that they’ve taken in more than the $200,000 which is listed in the public domain.

Beginning in 2004, the French National Center for Scientific Research (CNRS) has been focusing their efforts on a Molten Salt Fast Reactor (MSFR), a fast spectrum MSR with a thorium fuel cycle. Unlike thermal molten salt reactors, the MSFR doesn’t use any solid moderator, making it a fast-spectrum reactor with the possibility of fuel reload without reactor shut-down (we have no idea what that means either). Scientists find the technology exciting, but its definitely in the beginning stages of development. French analysts predict that deployment of the MSFR would likely be post 2050, around the same time that the last human jobs will be migrated to robots and AI.

Founded in 2010, Transatomic has taken in 3 rounds of funding totaling $5.5 million from investors that included Peter Thiel. The Company is developing their “Waste-Annihilating Molten Salt Reactor” (WAMSR) (fcuk yes) which is a 520 MW molten salt reactor which uses the waste from traditional reactors as a fuel source. Here’s a look at their milestones and progress:

While a traditional reactor may use up to 4% of the energy in their uranium fuel, the WAMSR utilizes 96% consequently reducing nuclear waste to 2.5% of what is produced by a typical reactor. Overnight cost of the WAMSR is $1.7 billion, and they are currently running lab-scale experiments to refine the design for the prototype facility which is expected to be complete by 2020.

UPDATE: The same day this article was published, MIT published an article titled “Nuclear Energy Startup Transatomic Backtracks on Key Promises“. Long story short, it went from being 75X more efficient to 2X more efficient and investors said they were still confident in the company’s mission.

Next up is a company called Martingale (of which little information could be found) which is developing an MSR called Thorcon. The Company claims that their decades-old original Molten Salt Reactor design needs no new technology, is completely fixable, and rapidly deployable. They also claim that their cheap, reliable, CO2-free electricity is here, NOW. They have a written and published prototype test schedule that requires just five years, and a cool $170 million in funding.

UPDATE 2/27/2017: Here is an update from Robert Hargraves, founder of Thorcon:

Regarding ThorCon, the IP assets of Martingale have been transferred to ThorCon International Pte Ltd, a Singapore corporation. Over a year ago we signed a MOU with 3 Indonesia state-owned companies to pursue our thorium/uranium liquid fission power plant.

Our team is in Indonesia, again. Indonesia finished the “pre-feasibility study”. We’re working closely with their universities, ministries, nuclear energy agency, and the regulator. They are working on an assessment guided by IAEA INPRO. Demonstration site is chosen. Discussing plans with vendors for turbines, generators, graphite, salt, pumps, and shipyards. Raised most of the $10 million first round.

Founded in 2011, Flibe proposed to use thorium as a nuclear fuel instead of uranium. The founder Kirk Sorensen, both a nuclear engineer and rocket scientist, claims that corporate interests have prevented thorium from being used as a nuclear fuel. Flibe’s liquid fluoride thorium reactor is expected to cost several hundred million dollars to build. They’re looking for partners and if you want a thorough look at what they’re proposing, this deck is pretty informative once you get past the intro slides. If you just want a quick schematic instead, here is the “Liquid-Fluoride Thorium Reactor” or LFTR:


In the same location as it says on the tin, Copenhagen Atomics is the brainchild of two gentlemen who see the same potential for thorium as does Flibe Energy. The startup is focused on solving the challenge of nuclear waste with a Thorium Molten Salt Reactor called the “Waste Burner”. On their website is a white paper on their technology dated back to November 2014 and they have a team of 16 people working on the project. They also appear to have posted some information on Quora in 2015 which should be taken with a grain of salt because that could be anybody posting.

Now this is where things get a bit weird. There’s another Danish firm doing the exact same thing. It’s not just they’re both developing a Thorium Molten Salt Reactor, it’s that they’re even named the same. Seaborg’s reactor is called the “Wasteburner” while the Copenhagen Atomics’ reactor is called the “Waste Burner”. They both have a similar looking layout for their websites. They both have a single white paper (here is the one from Seaborg) that from our layman’s eyes doesn’t look all that different to the one from Copenhagen Atomics. If we didn’t know any better, we’d say there was a falling out at Copenhagen Atomics at some point and Seaborg spawned off as a result of that. Do you think they go out for drinks and swap notes or is it just awkward chance encounters at the local bar? Fascinating stuff.

With the exception of the companies that have received meaningful amounts of funding, it seems like everyone else is actively seeking funding and hoping some investor ponies up 10s of millions of dollars to start building their own superior version of the MSR. There is certainly interest from retail investors because we see a lot of Google searches for terms like “Flibe Energy stock symbol” or “Terrestrial Energy stock”.  The problem is that even if these startups turn to crowdfunding, they just won’t be able to raise the type of money they’re looking for from the average retail investor who wants to take a punt with a few grand. The fastest dog on the track at the moment, and the one with the deepest pockets, seems to be Terrapower which claims they will enter the “construction phase” in 5 years’ time.

If you have a dog in the MSR race and you think you’re further ahead than Terrapower, drop us a note in the comments section below.

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  • Matt Musson

    Molten Salt Reactors have a Business Case Problem.

    The Uranium Reactor Builders lock their customers into a long term requirement for their own machined fuel rods. Like Kodak selling cameras that required Kodak film – this was a lucrative ongoing revenue stream. MSLT reactors use bulk chemicals. No locked in revenue stream.

    • Nanalyze

      Good point Matt

    • Ike Bottema

      No need to lock in business with the old razor-blade technique: there will be more than enough business just installing new reactors!

    • Alberto R.

      Kodak in the end died and current (digital) cameras use cheap generic SD cards. Of course the new winners won’t be the old ones. Westinghouse-Toshiba already bankrupted.

    • Hey, guys. We don’t have an MSR but we do have a GenIV advanced reactor. Ours is a 200MWt high temperature gas cooled pebble bed reactor, the Xe-100. We were awarded a $40M DOE award in 2016 and our Founder/CEO Kam Ghaffarian has invest thus far $32M of his own money. See more here: Would love to discuss further.

      • Alberto R.

        Never heard about your company, Melanie. I’ll watch your website. Good luck!

      • Nanalyze

        Thank you for the added info Melanie! Looks like you have some meaningful $$$ to commercialize with. How long until you’re feeding electricity into the grid?

        • We are aiming for deployment ready in 2025. Check our twitter feed for updates: @xenergynuclear

    • Marcelo Pacheco

      Actually that’s not a problem with MSRs.
      Water cooled reactors are expensive to build. Very expensive.
      Simplified MSRs like Terrestrial IMSR are so much cheaper. Like 10% as much cost.
      In fact the IMSR has a similar concept. Its rated for only 8 years operation in its higher power configuration (300MW electric).
      The sites will be built with twin reactor slots, such that when the 8 years are up, power production can be switched between the old and a new reactor on the fly. The old reactor than cools down in place until its slot is needed 8 years later. Its then moved from one of the active slots to one of several secondary slots.
      With its spent fuel removed, the reactor can then be shipped back to the factory for refurbishment and reuse.
      So there’s also the same “razorblade” analogy.
      But fundamentally, the IMSR is designed to be factory built much like a Boeing 737 is made (over a dozen a month). The reactor core is small enough it can be shipped in just one or two truck loads with very little nuclear specific work left on the side.
      Most of the on site work uses the exact same skills required to build a natural gas or coal power plant.
      There are several reasons why your comment is wrong.
      Water cooled nukes are the equivalent of WWII piston aircraft.
      MSRs are the turbine equivalent. Far, far, far more reliable. Much easier to construct and maintain. Much cheaper too. The sole different is turbine aircraft are usually much bigger than the old piston planes, while MSRs tend to be smaller than current water cooled nukes (precisely because this allows for cheaper serialized construction).

  • Regarding ThorCon, the IP assets of Martingale have been transferred to ThorCon International Pte Ltd, a Singapore corporation. Over a year ago we signed a MOU with 3 Indonesia state-owned companies to pursue our thorium/uranium liquid fission power plant.

    Our team is in Indonesia, again. Indonesia finished the “pre-feasibility study”. We’re working closely with their universities, ministries, nuclear energy agency, and the regulator. They are working on an assessment guided by IAEA INPRO. Demonstration site is chosen. Discussing plans with vendors for turbines, generators, graphite, salt, pumps, and shipyards. Raised most of the $10 million first round.

    Learn more at

    Love to converse with you if you contact me.

    • Nanalyze

      Thank you for that additional information Robert. We’ll reach out to you and confirm this information then update the article.

      • Nanalyze

        We can confirm this was posted by Robert Hargraves. The article has been updated with Robert’s additional info.

    • Ike Bottema

      I’ll add a few observations to what Robert Hargraves mentioned. While there’s little about Martingale, it’s more of a financial holding company. Thorcon is where it’s at. Actually of all the MSR efforts you’ve mentioned, Thorcon has the most comprehensive design details publicly available including detailed costing estimates (see Executive Summary at their web site). Of course as they advance through design certification processes, no doubt there will be changes however what’s there should give you a better idea as to why Thorcon and other MSR developers are so optimistic about the technology.

      • Nanalyze

        Thank you for the additional info Ike!

  • David Dyck

    You need to expand your coverage to include China and India. Companies/governments in these two countries are probably in the lead regarding development/deployment of the molten salt reactors. And as in any new market whomever gets to market first will probably control the market. If the US does not want to be paying royalties to an Chinese or India company/government on its energy production for the next hundreds of years it needs a joint, coordinated effort between the companies listed above, the DOE, NRC, even the DOD to develop and construct molten salt reactors soon.

    To that end contact your senators to support HR 590 (House bill 590 which as passed the House and is now in committee in the Senate) which requires/requests the Department of Energy to allocate resources to define the regulatory requirements for molten salt reactors.

    • Nanalyze

      This is a great point David and something we noticed while doing research.

      It’s a bit ethnocentric of us not to include foreign players but we really needed to address that in a separate article which we’ll look to do. Any info you might have about companies in either China or India would be much appreciated to get the article kick started!

  • Erica Gray

    Nuclear Energy Startup Transatomic Backtracks on Key Promises

    • Nanalyze

      Very timely article Erica, thank you for pointing that out! We’ll add a mention of that news in our article since the MIT article was posted the same day as ours.

      Does anyone else think that the CEO of Transatomic Power has that whole Elizabeth Holmes look about her in that article? Note that in the article the investors still show confidence so we’ll see what the demo reactor looks like in 2021!

  • Thanks for a good article! For further information you can go to

    • Nanalyze

      You are quite welcome. Thank you for the link to what appears to be a very active website with thorium news.

  • kent beuchert

    I have followed Transatomic and Moltex. From my vantage point I beleive that Moltex (and English company) has the most practical, ready to build and cheapest system design. They are claiming build costs of less than $2 per watt and levelized cost of power of less than $35 per MWhr, which would blow away every other technology. Renewables are political, not practical, power generators. They have received govt subsidies way above what they are worth and the removal of those subsidies and rules that require utilities to buy their rather worthless power will
    be their doom.

    • Nanalyze

      Thank you for the comment Kent

  • Ronaldo

    Thank you for the article. I’m very interested in the space. Who is the author of this article?

    • Nanalyze

      Hi Ronaldo,

      You are very welcome! We don’t use any bylines at Nanalyze so people focus on the message. We had several authors working on this article so feel free to contact us at [email protected] and we can put you in touch if you like.

  • Roman Voskoboynikov

    I am surprised that TMSR development programme at Shanghai Institute of Nuclear Applied Physics is not mentioned in the article. The programme has a budget of more than 300 million US dollars.

    • Nanalyze

      Thank you for that heads up Roman. We’ll look to do a follow up article on MSRs outside the USA.

  • Dear Nanalyze,

    Please allow me to clarify the situation between Seaborg Technologies and Copenhagen Atomics, which clearly is somewhat opaque to people not intimately knowledgeable of the (tiny) nuclear community in Denmark. Indeed, Seaborg Technologies and Copenhagen Atomics share common roots.

    Back in the days, the founders of Seaborg were a group of particle-, nuclear- and neutron-physicists, with common history through CERN. To maintain our friendship we met to brew beer and discuss molten salt reactors (MSRs). Finally we formed the organization “Reactive”, which today is the company Seaborg. Back then we did MSR neutronics just for our own interest.

    Around the same time, a small public MSR meetup community appeared in Denmark, started by Thomas Jam. Naturally we started attending. Thomas Jam wanted to build a MSR in a container, and we thought the idea interesting, so we formed another organization, called Copenhagen Atomics.

    However, somewhere down the line (early 2015), we decided to leave Copenhagen Atomics due to professional differences. We renamed Reactive into Seaborg Technologies and registered it as a proper company.

    So to answer the questions:
    1: Copenhagen Atomics still hosts the monthly public MSR meetup in Copenhagen, and we in Seaborg attend whenever possible – typically this result in us enjoying a beer together afterwards.

    2: The technical similarities back then are in fact quite natural, since we helped them doing their neutronics and reactor physics, just as we have been doing, and still do, neutronics for other MSR start-ups such as FLiBe and Moltex. But today Copenhagen Atomics and Seaborgs designs have grown apart. For instance, we dropped the constraint of building the power plant in a container, and they have change moderator and are now developing a heavy water moderated molten salt reactor.

    3: The similarities between the whitepapers likely originate from the fact that we wrote parts of their whitepaper – the layout might be similar because both whitepapers are based on the LaTeX template of one of the Seaborg co-founders his Ph.D. thesis – which I by the way also used for my Ph.D. thesis.

    Now, enough history… If you want to know what we do in Seaborg – please feel free to contact us 🙂

    Troels Schönfeldt
    CEO, Seaborg Technologies

    • Nanalyze

      Thank you very much for taking your time to explain that to our readers Troels! We’re always fascinated by the dynamics of how startups sometimes break into multiple companies and it’s great to hear you’re all enjoying beers together. We’ll be sure to reach out to you with questions should we do another article on this topic. One of our writers is originally from Odense and he says Hej. When we’re in the neighborhood we’ll be sure to come by and see what you’re getting up to!

  • Ville Tulkki

    Do note that Terrapower’s TWR is not a MSR but a version of sodium cooled breeder with solid fuel. They’re looking into a MSR design also but that’s more in the concept phase. So Terrestrial is most likely lead in the West, having submitted their design to Canadian pre-licensing.

    • Nanalyze

      Thank you for the clarification Ville

  • Rod Coenen

    Those who mention the importance of contacting members of congress are spot on. Congress seems unable to distinguish politics from technology , or science, or myth, or anything else for that matter. Maybe they can be lured to believe MSR is politically good.

    Help them understand the going backward black hole of most wind and solar. Without wind and solar advanced nuclear is the only remaining path forward. Fossil fuel is self extinguishing from competition and transportation cost. Money from Congress for MSR would be nice but that comes after new nuclear gets appropriate permitting, regs, licensing, carbon free credits and a little respect.

    The appeal to left, right, and Trump gospel ought be indisputable, glaring, blatant, or as plain as the nose on our faces. Can we get reality to defeat both carbon and radiation fear? Talk to Congress.

    • Nanalyze

      Thank you for the call to arms Rod.

      When you say “black hole of most wind and solar”, the prevailing technology will be the most economical. If MSRs finally make it to market then they would need to be cheaper before wind and solar go to the wayside. With all the great things we hear about thorium, that should be possible.

      Another reader remarked that “billionaire investors” are backing this. That’s true enough, but not with serious money. Why?

      • Rod Coenen

        Experience is accumulating on the total lifecycle cost of wind/solar. If we monetize the carbon foot print and include backup for w/s downtime, account for the w/s subsidy, recognize that w/s life span is 1/3 of nuclear, nuclear wins. Markets will at some point additionally recognize the health and eco-cost of carbon.

        Those “billionaire” investors need more certainty that DOE, EPA and NRC are fully supportive of MSR, which is why I say we need to pour on the heat to congress and the administration.

        • Alberto R.

          “Renewables” are a scam, anyway. When the scam will be finally and definitely exposed that fake industry will inevitably die. Carbon dioxide is GOOD. Carbon dioxide is LIFE.

          • Nanalyze

            No trolling man


    Transatomic back-pedalling? I should say!
    UPDATE: The same day this article was published, MIT published an article titled “Nuclear Energy Startup Transatomic Backtracks on Key Promises“. Long story short, it went from being 75X more efficient to 2X more efficient.

    Biggest ‘deficit of trust’ [diplomatic term for ‘lie”] in business history, barring the South Sea Bubble. DON’T TOUCH THEM.

    • Nanalyze

      Hah. A “trust deficit”. Excellent term to use in group meetings.


    Thorcon is the closest to a working MSR; read their full story. Their approach is completely different to ‘accepted’ reactor construction and it’s ‘norms’.
    4-year refuelling & re-conditioning on-the-fly, modular construction by proven shipyard methods, flexibility in adding modules without shut-down, match power requirement to local demand, etc, etc.
    China or India are years behind, re-working much the same ground as previous research. NO other company is any where near a practical thorium reactor.

    • Nanalyze

      Thank you for the comment. Based on the update we provided about Thorcon (from the founder’s mouth), that would appear to be the case!

  • > If you have a dog in the MSR race and you think you’re further ahead than Terrapower, drop us a note

    Not my dog, but given Thor Energy’s claims for “operations … expected by 2023”, they may be about even with Terrapower.

    • Nanalyze

      Thank you very much for that! We hadn’t come across Thor Energy before and it’s good to have a list of all players in one place.

      • Troels

        Thor Energy develops a reactor fuel for conventional light water reactors, it has nothing top do with Molten Salt Reactors.

        Their main “product” is a conventional mixed oxide (MOX) fuel, similar to conventional reactor fuel but where they have added a fraction of thorium. While only a fraction of the thorium is consumed in the reactor fuel cycle, the thorium based MOX have some advantages, which helps improving the fuel economy.

        In fact most present MSRs designs doesn’t use thorium at all and I would not expect those which does to be first to marked. In my view, there is no doubt that MSRs are coming, but by now it should be clear that what “would appear to be the case” does not really matter…

        • Nanalyze

          Thank you for the clarifications!

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