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This is a passionate team working on a very hard problem. They have guts and skills. I've always loved microreactors for fringe remote power where people are wi

This is a passionate team working on a very hard problem. They have guts and skills. I've always loved microreactors for fringe remote power where people are willing to pay 20x more than normal diesel generator prices. Like Antarctica, remote bases, the moon etc. Trying to make microreactors cheap is super hard. We've obviously tried it many times, the most relevant being the truck-mounted military microreactor ML-1 (the only closed-cycle direct gas turbine reactor ever operated) https://en.wikipedia.org/wiki/ML-1 https://en.wikipedia.org/wiki/ML-1. Shielding is hard. Even a small reactor this size needs like 8 ft. of high density concrete on all sides, or equivalent, plus 4-6" of a heavy metal like tungsten to take down the gammas. You can't just put it underground because the neutrons activate the dirt. Driving it off afterwards is borderline impossible because you generally have to put the spent fuel in robust canisters that can handle collisions, rollovers, and RPG attacks. But the hardest part is fuel cost. This reactor uses medium-enriched ('HALEU') fuel, which is super expensive, and then it packages it into TRISO form, which is about 100x more expensive to fabricate than regular UO₂ fuel. On the plus side, it's super robust and can minimize the need for other safety systems. Those prices could both go down, conceivably, but the fab process is pretty intricate, and it's hard to bring down enrichment costs. In my analysis, the fuel cost alone nearly makes this kind of reactor uncompetitive with a diesel generator in almost all applications. So even if the reactor is free (because you build it on an assembly line?), you're still out of luck. Then there's thermal strain. When you're a small reactor you have big gradients. This bends things. Neutrons make it worse. Then you have a tiny box with electronics in it getting absolutely hammered by neutron dose. That does bad things too. I hope they can find a way to bring fuel costs way down. I really like the people at this company, and I really like nuclear power and want to see it used in many new applications. I just don't quite see the path yet.

no_wizard 1y ago
Wonder if much of the world didn't turn away from nuclear power they way they did since the 1960s, if we wouldn't have solved alot of problems like these already given research was stagnant (relative to other research in power generation) for a very very long time.
- acidburnNSA 1y ago
  It'd be a much different field if we had kept it up. I spend a lot of time in nuclear archival material, and facilities like CANEL in Middletown CT absolutely blow my mind. They had hundreds of people working on crazy reactor technologies. They were flowing white-hot lithium metal at 100 mph. But yeah we gave all that up. My friend wrote a pretty good article about this not long ago https://www.ans.org/news/2025-05-08/article-6961/hightemperature-plumbing-and-advanced-reactors/ https://www.ans.org/news/2025-05-08/article-6961/hightempera...
  - binary132 1y ago
    In order for this to happen, making websites and mobile apps is going to have to get a lot less lucrative.
ortusdux 1y ago
> I hope they can find a way to bring fuel costs way down. I've spoke with some researchers and investors working on seawater uranium extraction and left quite optimistic.
- philipkglass 1y ago
  Extracting uranium from seawater gives you natural uranium, which needs to be enriched for use in most power reactors. The reactor under discussion here needs higher uranium enrichment and more expensive fuel fabrication operations than common power reactors. Developing uranium extraction from seawater is a good long-term insurance plan for uranium availability, but it's not going to help this reactor get its fuel costs down.
cyberax 1y ago
> On the plus side, it's super robust and can minimize the need for other safety systems. Can it survive 20 kilos of TNT planted by a terrorist?
- whamlastxmas 1y ago
  Can a skyscraper?
- acidburnNSA 1y ago
  If they radiation shield it properly, I'd like to think so. That won't do anything to 8 ft of concrete plus 4" of tungsten. Plus the fuel form holds in a lot of the fission products even when scattered around. It may overheat and release volatile fission products but I don't think it would be a widespread disaster no matter what.
  - Atotalnoob 1y ago
    Could you reduce the amount of concrete by increasing the amount of tungsten?
    - acidburnNSA 1y ago
      Not really. You have to stop neutrons and gammas. Concrete does neutrons but not gammas, tungsten does gammas but not neutrons. You can also use water on neutrons or lead on gammas. There are many combos and composites. Oh and neutrons cause more gammas when they get absorbed. Sometimes there are repeated layers, 3 or 4 times. If you have even tiny impurities in your shield you can get huge unexpected capture gammas It's a rich tradition for reactors to start out with too little shielding though. Like the Japanese nuclear powered cargo ship Mutsu fired up for the first time, realized they didn't shield well enough, and spent 4 years fixing/retrofitting more shielding.
      - LargoLasskhyfv 1y ago
        Is anybody considering the research into and use of metamaterials for shielding instead? Like 2D-twisted-hyperhexasomething?
AnthonyMouse 1y ago
I don't really get the "make it small enough to fit on a truck" thing. The main impediment for nuclear is cost, and then being able to build reactors on an assembly line would be a significant advantage. But how much of that advantage is retained if the product comes on more than one truck and the thing that comes is the reactor, the fuel and the turbines whereas the concrete gets poured on-site? It seems like that should get you nearly all of the cost savings from mass production but then you get a full-sized reactor that can power a city instead of something that can only replace a diesel generator.
- godelski 1y ago
  I think you're missing some use cases and some parameters. For the average home, this doesn't make sense. But for a hospital? A data center? There are plenty of places that are happy to pay a premium for an independent, redundant, and/or emergency power source. Somewhere like a hospital is going to get big advantages from something like this because it not only provides electricity but hot water (reducing the electrical demand that would go to hot water creation). There are also big advantages to remote places. Getting power in Alaska[0]. It's even difficult to get it in places like Alberta or Montana, both of which will also would take advantage of the heat source. Even at 5 years, this is more reliable than something like a gas generator and has a lot of logistical advantages. This says it does 1MW or electric power and 1.9MW of thermal. I found a 1MW generator[1], and it looks to consume between 77-87 gal/hr. A gallon weighs 7lbs, so 80 gal is 560lbs and takes 0.3m3. At one day's consumption (1920 gal) you need to be able to store over 13klbs and it'll take up 7.3m3 (not including the volume of the container and that it needs to be stored somewhere that is dry but also well ventilated). On top of that, diesel has a self life of 6mo (can extend to a year), so you're going to be doing a lot of deliveries... Given that, I can see a lot of places that would gladly make those trade-offs. Also, if it can fit self-contained in a container, the parts are going to be much smaller. You gotta start somewhere, right? Doesn't seem a bad idea to start with edge customers who are willing to pay a premium. [0] https://app.electricitymaps.com/zone/US-AK/72h/hourly https://app.electricitymaps.com/zone/US-AK/72h/hourly [1] https://mart.cummins.com/imagelibrary/data/assetfiles/0070366.pdf https://mart.cummins.com/imagelibrary/data/assetfiles/007036...
ViewTrick1002 1y ago
I have a hard time seeing how communities that have trouble keeping the skills necessary to operate diesel generators will be able to switch to nuclear reactors. https://www.spitsbergen-svalbard.com/2024/04/09/longyearbyen-has-got-the-power.html https://www.spitsbergen-svalbard.com/2024/04/09/longyearbyen...

no_wizard 1y ago

Wonder if much of the world didn't turn away from nuclear power they way they did since the 1960s, if we wouldn't have solved alot of problems like these already given research was stagnant (relative to other research in power generation) for a very very long time.

acidburnNSA 1y ago
It'd be a much different field if we had kept it up. I spend a lot of time in nuclear archival material, and facilities like CANEL in Middletown CT absolutely blow my mind. They had hundreds of people working on crazy reactor technologies. They were flowing white-hot lithium metal at 100 mph. But yeah we gave all that up. My friend wrote a pretty good article about this not long ago https://www.ans.org/news/2025-05-08/article-6961/hightemperature-plumbing-and-advanced-reactors/ https://www.ans.org/news/2025-05-08/article-6961/hightempera...
- binary132 1y ago
  In order for this to happen, making websites and mobile apps is going to have to get a lot less lucrative.

ortusdux 1y ago

> I hope they can find a way to bring fuel costs way down. I've spoke with some researchers and investors working on seawater uranium extraction and left quite optimistic.

philipkglass 1y ago
Extracting uranium from seawater gives you natural uranium, which needs to be enriched for use in most power reactors. The reactor under discussion here needs higher uranium enrichment and more expensive fuel fabrication operations than common power reactors. Developing uranium extraction from seawater is a good long-term insurance plan for uranium availability, but it's not going to help this reactor get its fuel costs down.

cyberax 1y ago

> On the plus side, it's super robust and can minimize the need for other safety systems. Can it survive 20 kilos of TNT planted by a terrorist?

whamlastxmas 1y ago
Can a skyscraper?
acidburnNSA 1y ago
If they radiation shield it properly, I'd like to think so. That won't do anything to 8 ft of concrete plus 4" of tungsten. Plus the fuel form holds in a lot of the fission products even when scattered around. It may overheat and release volatile fission products but I don't think it would be a widespread disaster no matter what.
- Atotalnoob 1y ago
  Could you reduce the amount of concrete by increasing the amount of tungsten?
  - acidburnNSA 1y ago
    Not really. You have to stop neutrons and gammas. Concrete does neutrons but not gammas, tungsten does gammas but not neutrons. You can also use water on neutrons or lead on gammas. There are many combos and composites. Oh and neutrons cause more gammas when they get absorbed. Sometimes there are repeated layers, 3 or 4 times. If you have even tiny impurities in your shield you can get huge unexpected capture gammas It's a rich tradition for reactors to start out with too little shielding though. Like the Japanese nuclear powered cargo ship Mutsu fired up for the first time, realized they didn't shield well enough, and spent 4 years fixing/retrofitting more shielding.
    - LargoLasskhyfv 1y ago
      Is anybody considering the research into and use of metamaterials for shielding instead? Like 2D-twisted-hyperhexasomething?

AnthonyMouse 1y ago

I don't really get the "make it small enough to fit on a truck" thing. The main impediment for nuclear is cost, and then being able to build reactors on an assembly line would be a significant advantage. But how much of that advantage is retained if the product comes on more than one truck and the thing that comes is the reactor, the fuel and the turbines whereas the concrete gets poured on-site? It seems like that should get you nearly all of the cost savings from mass production but then you get a full-sized reactor that can power a city instead of something that can only replace a diesel generator.

godelski 1y ago
I think you're missing some use cases and some parameters. For the average home, this doesn't make sense. But for a hospital? A data center? There are plenty of places that are happy to pay a premium for an independent, redundant, and/or emergency power source. Somewhere like a hospital is going to get big advantages from something like this because it not only provides electricity but hot water (reducing the electrical demand that would go to hot water creation). There are also big advantages to remote places. Getting power in Alaska[0]. It's even difficult to get it in places like Alberta or Montana, both of which will also would take advantage of the heat source. Even at 5 years, this is more reliable than something like a gas generator and has a lot of logistical advantages. This says it does 1MW or electric power and 1.9MW of thermal. I found a 1MW generator[1], and it looks to consume between 77-87 gal/hr. A gallon weighs 7lbs, so 80 gal is 560lbs and takes 0.3m3. At one day's consumption (1920 gal) you need to be able to store over 13klbs and it'll take up 7.3m3 (not including the volume of the container and that it needs to be stored somewhere that is dry but also well ventilated). On top of that, diesel has a self life of 6mo (can extend to a year), so you're going to be doing a lot of deliveries... Given that, I can see a lot of places that would gladly make those trade-offs. Also, if it can fit self-contained in a container, the parts are going to be much smaller. You gotta start somewhere, right? Doesn't seem a bad idea to start with edge customers who are willing to pay a premium. [0] https://app.electricitymaps.com/zone/US-AK/72h/hourly https://app.electricitymaps.com/zone/US-AK/72h/hourly [1] https://mart.cummins.com/imagelibrary/data/assetfiles/0070366.pdf https://mart.cummins.com/imagelibrary/data/assetfiles/007036...

ViewTrick1002 1y ago

I have a hard time seeing how communities that have trouble keeping the skills necessary to operate diesel generators will be able to switch to nuclear reactors. https://www.spitsbergen-svalbard.com/2024/04/09/longyearbyen-has-got-the-power.html https://www.spitsbergen-svalbard.com/2024/04/09/longyearbyen...