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Kaleidos – A portable nuclear microreactor that replaces diesel generators
- idontwantthis 1y agoIs it real?
- cactacea 1y agoFrom their job listings: > Additional Requirements > Must be willing to work extended hours and weekends as necessary to accomplish our mission. So... not yet.
- kwhitefoot 1y agoI was hoping the FAQ would answer that but, as I expected, I was disappointed.
- acidburnNSA 1y agoYes it's real. There are a lot of good people who I know personally and a lot of funding going into this. They have a plan to get fuel and will try to turn the first one on in Idaho soonish (like next year)
- wmf 1y agoIt will be tested next year so it's not real yet. https://radiantnuclear.com/blog/dome-selection/ https://radiantnuclear.com/blog/dome-selection/
- can16358p 1y agoSounds too good to be true. Hope it is true though.
- EA-3167 1y agoI have no idea if the testing will go well, if the regulatory/political environment will accept it, but as far as the company, the tech and the promise of testing? That is real. https://www.energy.gov/ne/articles/radiant-completes-study-first-kaleidos-microreactor-experiment https://www.energy.gov/ne/articles/radiant-completes-study-f...
- trklausss 1y agoI'm skeptical, not because it can't be achieved, but because it's not that practical. Diesel generators are "great" because diesel doesn't evaporate. You can have it there for years, and with good design, it just springs up the next day. This nuclear reactor has to be connected for fleet monitoring if you want to operate it. Which excludes it from many real life scenarios where diesel generators are used. Maybe for remote locations where constant power is needed (Antarctica and such), but I see their uses being very limited.
- p1mrx 1y agoIf I Google "diesel shelf life", the most common answer is 12 months. Do you have a better source? Propane probably makes more sense for fuel that needs to sit around for years. Do you know the shelf life of TRISO fuel? I imagine it doesn't matter because it would be very expensive to build a reactor and not switch it on.
- SR2Z 1y agoDiesel will degrade with exposure to oxygen, but a diesel engine can burn pretty much any flammable liquid that you can meter out. It really comes down to the engine itself and if it can handle less-than-perfect fuel.
- whatever1 1y agoIt can even burn its own lubricant oil and die in a screaming runaway fashion!
- linuxguy2 1y agoHow much does it cost? Would love to buy one with the HOA and run our own micro-grid while exporting electricity to the local utility.
- unglaublich 1y agoWhen HOA gets too powerful.
- salynchnew 1y agoWhen the DOE comes after your HOA.
- dylan604 1y agomeh, most HOAs can take on the DOD
- GuinansEyebrows 1y agoThis is bringing “My HOA went nuclear on me!” to a whole nother level.
- bostonwalker 1y agoNot in my back yard!!
- calvinmorrison 1y agoI have oil clients who would love this. they have to run expensive engines left and run on site
- wewtyflakes 1y agoThe poetic irony!
- ggm 1y agoA flame chart of energy consumption to customer from well-head typically shows an astronomical amount consumed at head in the gas train. It can be a significant sub of the total available energy consumed at the head and in pipeline and shipping, to produce the output which can be sold. Unfortunately much of it can't be sold or shipped off site and if it isn't used, will be fugitive gas emissions or flared. Replacing the diesel and other fuels used on-site is good. But it's only part of the story. Running the train would certainly burn a lot of gas, so replacing that would be good. (-not a fan of SMR for a variety of reasons, mostly political)
- dsadfjasdf 1y agoThoughts on using stranded gas as bitcoin miners?
- KaiserPro 1y agoFrom the headline I was assuming it was a tiny 20kw job. But it being a 1.9mw(thermal) makes sense. I wonder what the support requirements are, like how do you yeet the heat to make it efficient? Also containing super heated helium seems hard for any length of time. I wonder what the operating lifespan is.
- codezero 1y agoThey say five years before refueling and 20 years total lifetime.
- t0mas88 1y agoThey say it needs to be refueled after 5 years and that it can be done 4 times for a total lifespan of 20 years.
- Reason077 1y ago1.9 MWt still seems like a huge amount of energy/heat for something that fits on a truck and is supposedly air-cooled (they claim no water is required). Where does all that heat go?! They must have some very impressive fans.
- tralarpa 1y agoYes, that's crazy. They say up to 1 MW electric which would mean (33% efficiency) 2 MW of heat to get rid of with air cooling. Later they mention facility heating which sounds more realistic, I guess?
- KaiserPro 1y agoI mean its not that much different from a diesel generator, they are around 30% efficient, so they'd also be kicking out the same amount of heat? https://www.generatorsindustrial.com/products/1mw-diesel-generator-with-cummins-diesel-engine-kta50-g3 https://www.generatorsindustrial.com/products/1mw-diesel-gen... has a simple radiator. but then the heat profile is different I suppose, and the efficiency doesn't depend on being able to shed heat.
- mikewarot 1y agoAt this point, I'll assume that the relevant US regulatory agencies are competent, and skip the safety issues, etc. What does it cost? How much power can it deliver? So what's the equivalent $/KWh?
- jgeada 1y agoThat used to be true, not so sure my trust in our institutions is high these days. Seems a few million $ donation to the right people can make all regulations just vanish.
- acidburnNSA 1y agoYeah there's currently a large push to dismantle the Nuclear Regulatory Commission and give reactor regulation authorities to the states.
- jabl 1y agoFor all the faults of the NRC (real or imaginary), this still strikes me as an extremely bad idea.
- brink 1y ago> That used to be true No, that used to be believed to be true. We're just seeing the curtain come down. The food pyramid, the CIA's "war on drugs" in South America, the wars with Iraq, Libya.. Just to name a few. Why do we pretend like bribery and corruption is this new thing?
- croes 1y agoIf they go bankrupt who is responsible for the waste?
- gigel82 1y agoThat's the right question to raise up.
- lawlessone 1y agoyou are :D yikes from their FAQ: "The plan is for the small amount of spent fuel (the volume of the spent fuel in one reactor is equivalent in size to just two Walmart gas grill propane tanks) that comes out of our reactors at the end of their duty cycle to only be temporarily stored on-site until a federal repository or interim storage solution becomes available. " They don't even have plan while the exist now.
- acidburnNSA 1y agoWell no one does. The feds cancelled Yucca mountain and so there's nowhere for anyone to put nuclear waste. By law it belongs to the feds. So everyone just leaves it in the reactor's parking lot for now, in big concrete and steel dry casks.
- dylan604 1y ago> equivalent in size to just two Walmart gas grill propane tanks Is this a real measurement in tank sizes? Why not just say two 20lb tanks? What if I bought my tank from Home Depot? Are they a different size? Do they think using Walmart makes it more relatable?
- lawlessone 1y ago>Is this a real measurement in tank sizes? That's only 0.393% the size of a football field! Seriously though, isn't a lump of radioactive material that size actually huge?
- dylan604 1y ago
- daft_pink 1y agoWhen can I get a smaller one to power my AirTag?
- dylan604 1y agoI want one to take camping
- philipkglass 1y agoI know that this is a joke, but reactors cannot scale down that far. Unlike an electrical source powered by radioactive decay (like certain pacemakers [1]), the minimum mass for a nuclear reactor includes several kilograms of material. It's possible to shed neutron moderator mass by using high-purity fuel operating on fast fission, but these require more fuel to go critical so they still have multi-kilogram masses. [1] "Plutonium powered pacemakers (1974) https://www.orau.org/health-physics-museum/collection/miscellaneous/pacemaker.html https://www.orau.org/health-physics-museum/collection/miscel...
- Havoc 1y agoThat may actually be not that far away: >first nuclear battery can deliver 100 microwatts of power and a voltage of 3V >plans to produce a battery with 1 watt of power by 2025 https://www.independent.co.uk/tech/nuclear-battery-betavolt-atomic-china-b2476979.html https://www.independent.co.uk/tech/nuclear-battery-betavolt-...
- ACV001 1y agoA startup where most of the money were spent on that animation on the website.
- dylan604 1y agoYou'd be surprised at what the CAD software can do now in 3D renders. You have to design the thing in CAD anyways, so it's not like the 3D team had to model it from scratch. You could probably just do this with a request on Fivr. These aren't your parents 3D prices any more
- SoftTalker 1y agoAm I right that 1MW of solar generation would only take about a football field worth of panels? Of course that doesn't account for battery or other storage for nighttime, etc. but seems like it would be far cheaper and far less regulatory issues unless you really needed that much power generation in a very small footprint.
- generalizations 1y ago"Only" Looks like a giant part of the value is that it can be shipped in, dropped on the ground on site, turned on overnight, and it only takes up the footprint of a shipping container. If you have 24 hrs to find an empty football field within a powercable's distance of what you're trying to power, and then fill it with solar panels and batteries, you're gonna have a bad day.
- nehal3m 1y agoIf you ship in a stack of panels, inverters and cables, sure. But maybe you could be a little smarter about it, like a container with all the electronics (inverters, batteries, management) and a bunch of folded, pre-cabled panels that you can pull out across a field. If you bring a couple of those covering a field in a few hours shouldn't be that hard and could be ready for use instantly provided the batteries are charged at delivery.
- generalizations 1y agoYou also have to make sure there's an empty football field onsite. That's a much harder ask than dropping a shipping container in a couple of parking spots.
- supportengineer 1y agoThat is a solved problem https://en.wikipedia.org/wiki/BLU-82 https://en.wikipedia.org/wiki/BLU-82
- deleted 1y ago[deleted]
- jauntywundrkind 1y agoEverything I've heard is that micro-reactors produce far worse waste situations than larger scale options. I think there's a huge opportunity for nuclear power in the world today. But: all these micro-reactor strike me as disastrously bad idea, that's all too likely to offload incredibly complex nasty gross problem to the future. Costs that alas will likely be handled as network externalities, as drains and damage against humanity and people and government, that the creators and purchasers of these device will skate through with comparatively little injury.
- DoctorOetker 1y agoFrom a humanistic species survival perspective, we should conserve nuclear energy for interstellar travel.
- deleted 1y ago[deleted]
- 9dev 1y agoInterstellar travel to… where? It’s like saving your money for an immortality treatment that’ll eventually hit the market. Well yes it might, someday in the far far future. Practically speaking, this money should better be invested in your health now instead, aka. preservation of the only spaceship we have right now—Earth.
- DoctorOetker 1y agoTo different star systems obviously. Short of discovering portals or wormholes (natural or artificial), we should only assume demonstrated space propulsion technology to make the trip. With current technology its a long trip, and its cold and dark inbetween 2 stars. We should definitely conserve fissile materials until we demonstrate fusible materials for reliable power generation.
- XorNot 1y agoIf interstellar travel ever becomes possible you'd already have access to all the resources of the solar system as well as the output of the entire sun. The scale of the problem l, technologically simply renders earthbound resource constraints irrelevant. Like you're into "synthesize antimatter with solar power" at that point.
- ChuckMcM 1y agoLooks basically like the TRIGA reactor design (without the water shielding). Seems to have similar challenges with rapid load changes. At one time I thought NASA was looking at something like this tied together with a battery pack that would allow for rapid changes in dynamic load without a lot of stress on powering up/down the reactor. And now I can't find it. Sigh. If you're a billionaire building your bunker this would be the ultimate off-grid power source :-).
- acidburnNSA 1y agoIt's a lot different from a TRIGA. It doesn't have hydrogen in the fuel and it uses high temperature/high pressure helium gas as the coolant (vs. water in a TRIGA). We did run a nuclear reactor in space once that did use TRIGA fuel. It was called SNAP-10A. More recently, the Kilopower test ran a reactor on land but intended for space with a U-Mo metallic fuel.
- acidburnNSA 1y agoThis 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 agoWonder 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.
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- rob_c 1y agoFantastic if true. I'm sure there's a few catches or weed already have them back ordered globally but frankly anything that normalises using these self heating rocks to boil water gets my vote :)
- Peteragain 1y agoLooks aspirational to me. 1Mw electricity at 30-100% efficiency (100??) and 1.9 Mw heat via air in the volume of a shipping container? That's moving a lot of air. And I'd want fail safe, passive control "rods" (what happens if the helium leaks out and the heat isn't being removed) before I'd sleep easy with one in my back yard.
- gregbot 1y agoThis type of fuel basically cant melt so with no helium it would just heat up and natural convection would cool it.
- Peteragain 1y agoAnd everything around it? It is quite a challenge to design something that can do that.
- gregbot 1y agoYes. The fuel gets much hotter than the container
- ranie93 1y agoCould this be associated to a supposed recent State Department approval? “I just approved a program to deploy small modular nuclear reactors built in the United States to an allied country to help with their sort of energy infrastructure.” “Which allied country would that be?” “I can't tell you. It's not public yet.” From Interesting Times with Ross Douthat: The DOGE Alum Asking if Foreign Aid Is America’s Problem, Jul 31, 2025
- gmueckl 1y agoI'm not filled with optimism about this concept. Let's work backwards from crash safety (say a reactor on a truck getting t-boned by a freight train). The radioactive material needs to be held in an armored containment to avoid release. That would have to be roughly comparable to CASTOR containers in terms of its resilience. But these containers have limited capability of passive thermal energy dissipation (Google finds models that handle 10kW to 45kW thermal power generated in the interior). This would be approximately the ceiling for the direct thermal power output that is still reduced by limited efficiency of heat-to-power conversion. This is admittedly napkin math, but it should be good enough to set expectations.
- jillesvangurp 1y agoYou are thinking accidents. I think we need to be thinking deliberate attempts to compromise these things and all the security measures needed to mitigate against that. And most importantly, the cost associated with that. Which comes on top of already significant cost. The naive notion of we'll just ship these all over the place by the thousands and it's going to be fine is not going to withstand a lot of critical thinking very long.
- gmueckl 1y agoI was indeed not thinking about deliberate attacks. But that doesn't change the result much as I assume that the CASTOR containers that I used as reference are designed to withstand all of these worst case scenarios.
- conorcleary 1y agoUnfortunately, this chain of messages underscores the importance of keeping humans in check with eachother, and the machine.
- altcognito 1y agoHundreds of thousands if we're talking about meeting growing demand. Which doesn't give me a lot of hope for solar either though.
- metadat 1y ago1. Can I have one in my driveway? 2. Why only refuelable 4 times? 3. Is it really safe to fly around with in an airplane? Can major airlines help distribute these via standard flight routes to reduce cost? 4. What happens when home base monitoring detects a problem with the reactor? (And why isn't this covered in the slides to put the audience at ease?)
- MadnessASAP 1y ago> 3. Is it really safe to fly around with in an airplane? Can major airlines help distribute these via standard flight routes to reduce cost? These are too big for your standard air freight network or aircraft (that is, it's significantly larger then any typical ULD [Unit Load Device, shipping containers for airplanes]). So it'll definitely be a charter to get one delivered. Weights going to be the big determinant in cost, dimensionally it looks like you could get it into anything bigger then a C-130. I doubt you'll be within the C-130s weight limits though.
- AngryData 1y agoI would imagine refuelings are limited because at some point you are going to need to inspect and potentially replace some of the critical components that have been exposed to hard radiation. Materials that we would think of as stable can degrade in such high radiation environments. Like a large chunk of steel can have its crystal structure disrupted as atoms get displaced by high energy neutron strikes or other fission fragments, changing its material properties and making it weaker or in most cases more brittle. Localized impurities can also be formed by either alloying elements in the metal being displaced the same way, or from transmutation of atoms into other elements from the strong radiation. And along with disrupting the material strength those impurities can cause hot spots in the metal causing more stresses and fatigue and further reducing it's lifespan. We are actually pretty good at making alloys and materials today that can resist radiation problems better and more predictably these days, but there is still a bit of randomness from manufacturing variables that means you need a pretty large safety margin to prevent problems. They probably would work for a dozen refuelings, but the consequences of a reactor breech are too high to not have a massive safety margin. And maybe after they ran these for a few refuelings and inspected enough of them they could bump up the refueling limit before inspection or replacement a little.
- cyberax 1y agoThe USSR did it first! No, really. There was a mobile power plant: Pamir-630D ( https://imgur.com/a/rCexHAA https://imgur.com/a/rCexHAA ). It was even deployed to provide power to a remote Arctic outpost. It had to use an exotic coolant (basically, a rocket oxidizer) to make it work, and it had to be placed far away from anything else. The shielding was not enough to bring down the gamma radiation to a safe level when the reactor was active.
- actinium226 1y agoNot sure about who was first but McMurdo station in Antarctica was for a time powered by a nuclear reactor almost identical in power to the one being discussed here: http://large.stanford.edu/courses/2014/ph241/reid2/ http://large.stanford.edu/courses/2014/ph241/reid2/
- cyberax 1y agoD'oh. Thanks! I forgot about it, because it was delivered by a plane, not a truck.
- AngryData 1y agoNeat, I never heard of that! Im surprised there isn't even an english wiki page for it, I had to translate russian wikipedia and even that was a bit limited in information to satisfy my curiosity so ill have to look at other sources.
- cyberax 1y agoI actually was mistaken. The photo is from an earlier project: TES-3, from 1960. It was a system with 4 mobile units and a reactor that needed to be buried for shielding. https://www.ixbt.com/live/offtopic/pervaya-v-mire-peredvizhnaya-atomnaya-stanciya-proekt-tes-3.html https://www.ixbt.com/live/offtopic/pervaya-v-mire-peredvizhn... (German Wiki also has an article with an image: https://de.wikipedia.org/wiki/TES-3 https://de.wikipedia.org/wiki/TES-3 ). I remember reading about it in an encyclopedia as a child.
- 1shooner 1y ago>We have fully modeled worst-case - as well as lesser-case - scenarios for an accident or leak. The analysis has shown zero impact experienced by the public. Well that's a relief.
- hereme888 1y agoSo if the truck were electric, it could run for >5 years straight, even uphill? Jokes aside, very cool tech.
- 1970-01-01 1y agoNot a bad idea. But what if we scaled it up, say to 1.0GW. It wouldn't be portable, but it would sure be useful. So of course we instead take the fuel to the reactor. We could even call it a nuclear plant, because it doesn't move. Can we do that instead?
- Animats 1y agoHere's a related company, Ultra Safe Nuclear, making TRISO fuel units.[1] They went bankrupt in April 2025.[2] They at least got as far as making fuel units, although I suspect the video shows dummies being made, because they are not taking enough precautions for handling enriched uranium. [1] https://www.youtube.com/watch?v=uR7VDqUbaCg https://www.youtube.com/watch?v=uR7VDqUbaCg [2] https://nuclear-news.net/2025/04/04/update-on-the-bankruptcy-of-usnc-ultra-safe-nuclear/ https://nuclear-news.net/2025/04/04/update-on-the-bankruptcy...
- credit_guy 1y agoPro tip: if you want to check if a nuclear reactor design is vaporware or has real legs, you check their application with the NRC (nuclear regulatory commission). It turns out that the NRC does have a page for Kaleidos [1]. You can even go and see what documents Kaleidos submitted this month. They submitted a request to be exempted from some regulation called "10 CFR 55", which they feel is not applicable to them. I have no clue if that is the case or not, but at least they seem to be in fairly frequent contact with the NRC, and that's good news. [1] https://www.nrc.gov/reactors/new-reactors/advanced/who-were-working-with/pre-application-activities/kaleidos.html https://www.nrc.gov/reactors/new-reactors/advanced/who-were-...
- master_crab 1y ago10 CFR 55 covers operator licenses. The regulation does allow exemptions in certain cases where licensing isn’t necessary. https://www.ecfr.gov/current/title-10/chapter-I/part-55 https://www.ecfr.gov/current/title-10/chapter-I/part-55
- LatteLazy 1y agoLookslike more vapourware: * no prices * no dates, just "2026" (elsewhere 2028). * no pictures even of prototypes just computer graphics. * helium is notoriously hard to keep from leaking * it's all just way too promising and convenient and appealing. Who doesn't want a reactor that fits in a shipping container? Who doesn't want reliable, clean energy? Who doesn't like hospitals and the military? Does it also release puppies and cure cancer?
- Kon5ole 1y agoFrom the FAQ: > The plan is for the small amount of spent fuel [..] that comes out of our reactors at the end of their duty cycle to only be temporarily stored on-site until a federal repository or interim storage solution becomes available. >The NRC is legally required to ensure that, in the event of bankruptcy that the site is secure and the spent fuel remains safely managed before ultimately transferring over to the U.S. Department of Energy's (DOE) possession So basically like with all other nuclear, the tricky parts with unknown costs are handed over to future taxpayers. These costs are thereby removed from the estimates in Kaleidos business plan making it seem like it's a viable business, which is isn't otherwise. Meanwhile the founders get rich today, since immense amounts of money has to be presented upfront, before any energy is produced at all. The obvious replacement for diesel generators today is solar+batteries, which is evident in many countries that used to rely on small scale diesel generators already.
- m0d0nne11 1y agoBottom line: nuclear waste is forever while their promises are a fart in the wind. If they find any rules or regulations or judgements from any courts to be inconvenient they need only shove some cash up Trump's ass and then, POOF! all their problems are solved... except that, yeah, the waste will still be there. Oh, well - somebody else's problem. MAGA!