Update on Copenhagen Atomics Molten Salt Fission From CTO

Aslak Stubsgaard, CTO of Copenhagen Atomics provided an update to Nextbigfuture on their development of a Molten Salt nuclear fission reactor. They are a molten salt reactor company developing a 100MW(th) thorium molten salt reactors with an initial load plutonium from spent fuel. The reactors are designed to be roughly the size of a 40-foot shipping container and can be produced on an assembly line at low cost and scalable.

The goal is a walkaway safe reactor that is mass produced in a shipping container form factor.

They have chosen to validate a paper design through regulator pre-approval stages without building anything.

In 2019, they received two major danish grants. Copenhagen Atomics partnered with Alfa Laval who are one of the world’s leading heat exchanger producers and moved a majority of their lab facilities to Alfa Laval’s site in Copenhagen.

They are building pumped molten salt reactor loops, capable of pumping 700C fluoride/chloride salt. Copenhagen Atomics will soon open up for a public investment round.

Above, you see the molten salt loops currently under construction, in Alfa Laval’s production facility.

Let Brian Wang know if you have questions in the comments here. Aslak will be contacted and answers will be placed into follow up articles.

Walk-away Safe Shipping Container Reactor

The Copenhagen Atomics waste burner version 0.2.3 is a 50 MW(t) heavy water moderated, single fluid, fluoride salt-based, thermal spectrum, molten salt reactor. Copenhagen Atomics Waste Burner 2.0 and above versions are expected to be breeder and converter type designs, breeding more fissile material than consumed while converting fissile transuranic from existing uranium cycle waste to start a thorium-based cycle. The core, fission product extraction and separation systems, dump tank, primary heat exchanger, pumps, valves, and compressors are all contained in a leak-tight 40-foot shipping container surrounded by a shielding blanket of frozen thorium salt.

Target Application
The following applications are foreseen:
– Addon units at existing nuclear sites, coupled with a spent nuclear fuel reprocessing unit.
– Ship or barge-based power systems.
– Biofuel production and desalination plants.
– Baseload power in Asia and Africa.
The reactor design effort is focussed on a small modular thorium breeder thermal spectrum fluoride molten salt reactor, made to fit inside a 40-foot shipping container and with an initial fissile inventory made up of spent nuclear fuel transuranic.

They have moved beyond the conceptual stage to building and testing key components. The IAEA 2018 SMR book has details on this and all other Small Modular Reactor projects.

SOURCES- Copenhagen Atomics CTO Aslak Stubsgaard
Written By Brian Wang, Nextbigfuture.com

30 thoughts on “Update on Copenhagen Atomics Molten Salt Fission From CTO”

  1. Also, the light sails can be used to focus energy on much smaller solar panels, esp far from Sun. You only get half the thrust if you stop the light rather than reflect it, but you do get the energy.

  2. Take a large sheet of wax, aluminize it, boil off the wax and recover it, repeat. Easy in Space, hard on Earth, esp at large scales as vapor dep only works in vacuum. “until we have the materials” Al is common on the Moon. I totally agree with your time frame, unless G. K. O’Neill is right.

  3. Couldn’t the solar panels act as a light sail? Could that actually be a problem if there is more light push than the solar gravity? I guess it could be balanced by altering the orbital speed, as long as its less than 1:1?

  4. But until we have the materials to build those light sails in the size of km2, they remain science fiction.

    Theoretically they are possible, but we are very far to technically do so, probably centuries away.

  5. We have better materials today, and the temperatures are lower, but if it comes to the push, why couldn’t the blades be cooled in the same way?

  6. A 3-5 year design life means a huge amount of overhead for nuclear waste and transport of said waste. How much will it cost?

  7. You are right, but it is vastly better that molten salts.
    And still likely a dead end for economic feasibility. What does that inform us about the feasibility of molten salt reactors?

  8. I wrote that before I noticed the 3-5 year design life. I guess they DO have an engineering solution to the corrosion problem…..that then creates an insurmountable economic problem.

  9. In the 70’s, K. Eric Drexler proposed that with 1/10 of the mass of the load, light sails could be built that would balance solar gravity, and one could hang motionless anywhere in the solar system with comfortable temps and energy collection. Anywhere, in any direction, up to 10 times the distance to Neptune. A large volume!
    For current projects, we are close enuf, BTW.

  10. Not to mention Peak temperature in nuclear Brayton is going to be super low compared to combustion. That turbine is going to be a total dog

  11. it’s candu geometry, right? It’s conceivable that you could use flame-sprayed waspalloy tubes for the MS. I imagine that a 10 ft length of 3″ radius 0.05″ thick waspaloy tube, with aluminum oxide flame-sprayed onto the inner diameter, would be rather inexpensive. DP is prolly only like 5 bar or something (pump head); just hoop stress. This is the material they make afterburners, jet nozzles, and combustors from.

  12. Doesn’t the fuel combust completely before encountering the turbine blades?

    Or… thinking about the physics, does the higher specific heat of combustion products mean a lower final temperature for a given specific energy?

  13. No. Those have fuel injection. Or rather yes, but engineering-wise much less problematic because the fuel charge protects the turbine blades from destruction. Raw heated air gives no such blade protection. This is why none has ever been built. EDIT: There were some smallish prototypes, all failures.

  14. How about they build the non-existent reactor first before they worry about the non-existent turbines.

  15. Lead is also very aggressive at high temperatures . The Russian BREST 300 is supposed to have 540 C at the outlet. The proposed Swedish SEALER mini-reactor team have done a lot of work on corrosion- and erosion-( especially of the pump impeller) resistant steels, but only want to operate below 450 C.
    Moltex want to keep their chlorides in fuel tubes, so they can be changed out after a few years, without ever contacting the reactors’ surfaces ( barring leaks). They claim sacrificial zirconium inside the fuel tubes will keep leaching of chromium out of the steel to almost unmeasurable levels. They model heat transfer through the tube cladding as efficient enough to keep the metal at the mid-500s of the coolant outside it, not the up to 1000 C of the middle of the liquid fuel. Heat flow through the helium filled cladding gap of a light water reactor is much less efficient, but in normal operation the cladding stays hundreds of degrees cooler than the centre of the fuel pellets.
    Aircraft turbine blades operate in fast flowing, corrosive combustion gases that are hotter than the melting point of the very tough metals they’re made of. It’s tempting fate to say ‘never’ for chlorides. Especially when aluminium smelters are running at 960 C.

  16. Obvious question: How will you raise the billion Euros that will be necessary to build your first of a kind reactor, and where will you build it?

  17. So to rephrase your criticisms as questions:

    Specifically, what material will be use to hold the 700C molten salt and the fission byproducts?

    What is the estimated lifetime of this material at operating temperatures?

    How does thermal expansion impact the reactor design and does it contribute to stress fractures?

  18. So MSRs actually DO solve at least part of the dangerous waste problem? If so, what would be the feasibility of placing them on spacecraft for power? I grew up with the constant line of “All fission reactors produce waste, and you can’t make one that doesn’t”. Is that no longer true with these reactors? I’m still for hot fusion, but these seem like they would be great for a transition from the tractors we have now until we can perfect fusion.

    ^^^ See how I’m being all optimistic about fusion? I like to be a diehard optimist because, if I get let down hard, I get to pitty-drink hard!

    “Wow, you must be drunk ALL the time.”
    “It’s a matter of perspective, really.”

  19. Do any of you remember me asking the MSR fan crowd, particularly John Oneill, why nobody was trying to use water as the moderator in any MSR concepts..? I did; the comments were on a MOLTEX thread. I commented that an “inverse CANDU” geometry with insulated water tubes penetrating a calandria of MS would likely minimize the size of the reactor and give best thermalization.

    Now these Vikings are proposing the same thing. Little bit of vindication is a nice cap to a hell of a week. Brian, please give us an article about Oklo Aurora and their NRC submittal early this week. Good discussion can be had – something other than SpaceX or COVID19.

    I particularly appreciate this statement in the article; it diffuses my typical mode of attack:

    “They have chosen to validate a paper design through regulator pre-approval stages without building anything.”

  20. Other than solving existing nuke problem (waste radioactive stuff) this seems to mostly compete directly with Space Solar, eg Africa baseload. Cost estimates, compared to Criswell LSP?

  21. You cannot run a molten salt reactor at 700C with chloride salts without massive corrosion.
    You can melt FLiBe at 500C and it is actually MORE corrosive than chloride salts at that temperature, but the problem is corrosion massively increases in a non-linear fashion when you go from 500C to 700C (the temperatures needed for most chlorides), so the FLiBe reactor is actually feasible while the chloride salt one is absolutely not.
    If a paper molten salt reactor design wants to use chlorides, it will never ever happen.
    If you need super high temperatures you need to use something that does not cause massive corrosion at that temperature. Something like molten lead.

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