Thorcon Thorium Energy Converter Designs and Argonne National Lab Materials Analysis

ThorCon is a molten salt fission reactor. Unlike all current nuclear reactors, the fuel is in liquid form. It can be moved around with a pump and passively drained. This 500 MW fission power plant is encapsulated in a hull, built in a shipyard, towed to a shallow water site, ballasted to the seabed. ThorCon is a straightforward scale-up of the successful United States Oak Ridge National Laboratory Molten Salt Reactor Experiment (MSRE).

The complete ThorCon is manufactured in 150 to 500 ton blocks in a shipyard, assembled, then towed to the site. This produces order of magnitude improvements in productivity, quality control, and build time. A single large reactor yard can turn out twenty gigawatts of ThorCon power plants per year. ThorCon is a system for building power plants.

ThorCon has been working with the Indonesian government to add reliable electric power to the grid. In 2019 the Ministry of Energy began a study of the safety, economics, and grid impact of the 500 MW prototype ThorConIsle.

ThorCon is working with Argonne National Labs on material tests. They are moving to develop a non-fissile test plant to validate all aspects of the plant before progressing to a first of kind fissile reactor.

They are validating the seismic safety with simulations. They are validating the safety of shipping the reactor against the worst oceanic storms.

They target making the energy cheaper than coal from the reactor.

Indonesia had a target price for their energy and their analysis is that ThorCon will have lower cost than their target.

The final Indonesia recommendation report for the President of Indonesia is still being finalized.

Phase 1 is to build and test it with step by step commissioning, ending in a type license for future power plants.
Phase 2 is the shipyard production of ThorCon plants to provide an additional 3 GW of cheap, reliable electric power.

Dane Wilson recently retired from Oak Ridge National Laboratory. At ORNL, Dane worked on materials and systems for use in molten fluoride salts, high-temperature gaseous environments, and other pernicious working fluids of interest to energy and hydrogen production. Dane has a BSc in physics (solid-state), MS in material science and engineering and PhD in metallurgy (corrosion and surface science).

25 thoughts on “Thorcon Thorium Energy Converter Designs and Argonne National Lab Materials Analysis”

  1. I googled the seismic fault lines and volcanoes in and around Indonesia. It looks like a big mess and the area is basically surrounded and intersected by fault lines. Historically, some of the worst natural disasters the last millennium took place in this area. I’m no expert but staying away from that shoreline would probably be a good long term strategy.

    I almost bought property in Thailand in the late 90-ies. A small paradise like mini peninsula with bungalows, coconut trees, white beaches etc. Luckily, I listened to advice from senior members of the community there.
    Today, that piece of land doesn’t exist anymore. Looking at post tsunami satellite images, there is just water.

  2. Sure – everything built for a life in salt water is much more expensive. However, it’s unclear how half-submerging the construction in salt water would eliminate this problem.
    The cost is due to corrosion and maintenance associated with it.

    The massive damages caused by tsunamis are because the wavelength is very long. This causes a long lasting horizontal water flow that does not occur at all for normal waves unless they are breaking. It’s like sitting in a horizontal waterfall for as long as those waves last. In addition, the flow turns around and goes the other way when the waves stop. Then they bring a lot of debris causing even more damage.

  3. If you look at videos of the Tohoku tsunami, it’s pushing cars around, but not office blocks. The sea can smash anything up, given enough time, but things like lighthouses take massive waves for centuries. A competent engineer can build something to survive two or three big waves. You think it’s not that expensive to maintain a boat permanently moored, compared to a building ? It’s common knowledge that a boat is a hole in the water that you pour money into. Offshore wind turbines cost 60% more than onshore ones, maintenance costs are significantly higher, and floating ones are still at the prototype stage.

  4. Looking at modern time tsunami footage, it seems much safer to be floating some distance off the shore. If the depth conditions are right, the wave will be hardly noticeable. Why anchor it on the seabed? It’s not that difficult or expensive to build a floating ship and a cable.

  5. There is still no deal to build anything. There are various LOIs and MOUs, nothing else. Daewoo Shipbuilding has intended to do a feasibility study. But they don’t build plants, they build ships. Thorcon says Daewoo Ship “will” build the plant. That is impossible. Daewoo Engineering, on the other hand, builds plants (separate company from DS), and is NOT engaged in any of this, particularly since they got bought by Hyundai Heavy, who has no interest in this transaction.

    This is a typical “PR” exercise to try and show there is some actual progress when there really isn’t. There are no building permits, yet.

  6. IMO you just have to accept any of these side reactions and work with them. All they do is buzzkill the appeal of certain fuel cycles. If we eventually go to thorium, the side reactions will be a part of the whole balance. Not practical to eliminate them and burdensome to minimize other than to adopt the seed and blanket concept.

  7. Protactinium has a thermal neutron cross-section of 40 barns, which is pretty high. I guess enough of it survives long enough ( 30 day half-life ) to become U233, or they wouldn’t put such a neutron poison in the core. Capture cross-section of thorium 232 is 7.4 barns, and fission cross-section of uranium 233 is 531 barns.

  8. That would suggest there isn’t an easy means to make the salt volume in the dump tanks have a semi-solidified outer crust with a still molten center in a quick manner, to keep it from spilling back out of the tank if the tank is tipped/breeched. Keeping a tiny freeze plug frozen is about the limit of the available systems I guess? Though I was commenting in terms of tipping mostly, so I guess a high enough header pipe would solve tipping less than roughly 45 degrees, since going beyond that would probably lead to a rollover, and clearly the plant can’t handle getting tipped/rolled a full 90 degrees onto it’s side anyways.

  9. Oh, i don’t doubt it could be tipped or otherwise disrupted or broken-up. My ‘whatever’ was more about the dump tanks and ‘flash freezing’ this fuel salt when it makes 6% of full power the hour of shutdown and still +1% after 24 hours. Slop bucket gonna stay hot for a long time. They tend to size decay heat removal capacity in a way where system first heats up before decay heat decays to meet capacity and subsequently drops below capacity. Don’t cool to quickly. I recall ThorCon discussing peak temps in the high 900-990C in the dumps.

  10. It’s meant to be submerged, so it’d take one hell of a powerfull storm surge to move it. Not saying it can’t happen, just I expect it’d tolerate these things better than on land.

  11. Doesn’t the protactinium get destroyed as fast as it is created once it builds up to a quite low level?

  12. I believe their nominal siting effectively requires building a crude drydock, pushing the plant in, and then draining the drydock mostly. If the drydock floods from tsunami water ingress, it’s still more or less contained by drydock walls and floating (which it could already do).
    It would have to be a truly fierce tsunami to both fill the drydock fast enough and high enough to get the thing to float out beyond the drydock perimeter, and it would still likely be floating and in the process of dumping fuel to the dump tanks due to the tsunami warning. I suppose the biggest problem at that point would be the fuel still being molten in the dump tanks when the barge tips when it goes over the drydock perimeter or grounding out on some harbor area that isn’t flat. Depending on the dump tank design, it may not like being in a tilted position while dumped fuel is molten. Whether you could get around that risk by sufficient flash freezing of the salt surface so that it won’t slosh around depends on acceptable cooling rates for the dump tanks (want to avoid thermal shock cracking the container).

  13. ‘What could possibly go wrong?’
    A meltdown ? No, the fuel’s supposed to be molten. Coolant boiling and overpressurising the containment ? No, vapour pressure of the salt is too low, till you get to temperatures high enough to melt stainless steel anyway. Release of radioactive fission products ? No, iodine, strontium and cesium all form fluoride salts, which are not volatile. Zirconium-water reaction making heat and hydrogen ? There’s no water in the core, and no zirconium metal.
    I’m not saying nothing could go wrong – there’s a long history of failed reactor types – just that failure is unlikely to kill any member of the public. Some of the personnel, maybe. My cousin worked on a geothermal power plant in Indonesia, and had some interesting stories…

  14. You can’t just say that a country is subject to tsunamis. You have to identify the actual coast in question. The USA is subject to Tsunamis (in Alaska) but this doesn’t affect Florida.

    Indonesia has a bunch of different coasts, exposed to different oceans and hence different tsunami risks.

    Now I am not saying that the site they are looking at is safe. I would have to spend hours researching that and I don’t have the time, energy or motivation. But it is nowhere near the location of the recent tsunamis AFAICT.

  15. When a novel reactor type is developed, the non-paper projects start with a test loop, zero power, low power, and then scale up. Not because it takes years and a shipload of money, but because failure of a full scale plant is really not an option. As of July 2019, I see references to lots of talk and paper, and not even a test loop to show even the basic operation of something. Based on evidence, it is a classical paper reactor.

    On the point of protection, an aircraft engine falling from the sky is a strange choice of a threat. Tsunami is the obvious choice of a natural threat after Fukushima, and given the local conditions. For a man-made threat, such a facility would not be attacked by a falling engine; the obvious choice of vector would be a ship loaded with a few ISO containers of cheap explosives (such as ANFO), or a missile. Both threats point at an active defense perimeter requirement, which would also stop a falling engine, or a whole plane. That is how Russians protect NPPs, and for their floating plant they built a convincing seawall. Without that, powerpoint stories about falling engines is a paper protection for a paper reactor. Not good.

  16. They dont have a way to clean the unwanted radio-actives out of the salt to prevent it from going bad as protactinium builds up.

  17. Putting a reactor site on the bottom of the seabed in shallow waters off the coast of one of the countries hit hardest by tsunamis…
    What could possibly go wrong?

  18. I’m ‘hopeful’ on this – but having seen the Thorium salt reactors touted for close to 20 years now I’m ready for someone to build one of the damn things and show us what it can do.

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