9 ms·

Smaller reactors bring nuclear power closer to fulfilling its promise

159 points by sohkamyung 1mo ago

hvb2 1mo ago
> but SMRs should be cheaper and easier to construct. The word should is doing some real heavy lifting there. Especially given the subject. I guess we'll know in 2030 when one should come online.
- HPsquared 1mo ago
  We should know by then, at least.
- ViewTrick1002 1mo ago
  It just stupidly expensive if it is completed on time and budget. To make the figure at least palatable for public funding the project assumes enormous learning effects for subsequent reactors.
- agarwaen163 1mo ago
  Except Valar already did it earlier this year.
  - hvb2 1mo ago
    Not sure what you're referring to but in June they achieved criticality in a demo. While a good milestone that's not at all a functioning reactor connected to the grid. Let alone anything like a repeatable consistent production of said reactor.
soco 1mo ago
With solar and batteries getting cheaper and cheaper, is this still a topic? Or at least for the time being until that "cheaper" gets cheaper enough?
- petcat 1mo ago
  > In March 2025, the US Department of Energy (DoE) announced US $900 million in grants to support the deployment of SMRs. One year later, the European Commission said it would invest up to €200 million (US $228 million) in the construction of SMRs. Yes, it does seem to still be a topic.
  - jauntywundrkind 1mo ago
    And the US is spending vastly more to make sure renewables and solar don't get built. https://www.washingtonpost.com/business/2026/08/27/how-wind-projects-got-replaced-by-900-million-payday-trump-donors-firm/ https://www.washingtonpost.com/business/2026/08/27/how-wind-...
    - pfdietz 1mo ago
      > making sure If this is the goal, they're failing spectacularly.
- RivieraKid 1mo ago
  Solar + battery is very land inefficient, that's basically the main argument. Edit: Per ChatGPT's calculation, nuclear is significantly cheaper than solar + battery in my country (Czech Republic) if we're talking about adding new reactors to existing power plants.
  - actionfromafar 1mo ago
    But batteries can be very distributed and stabilize and prop up the grid in ways a huge plant can't without building out distribution. (Situation dependent of course.)
  - pfdietz 1mo ago
    Land is cheap. Even in Europe, the cost of land onto which renewables are put is small compared to the cost of the renewable energy equipment itself. Here in the US, it's common for the land to be just a few percent of the project cost.
hn_submit 1mo ago
Although generally safe these reactors aren't totally safe. I'm concerned lax physical security will allow miscreants to blow them up and spread nuclear materials over a wide area. The ensuing panic would totally destroy any goodwill nuclear power has gained over the last 20 years or so. I'm also concerned these things will mostly be used by Big Tech for their A.I. data-centers playing the Good Samaritan with their claims of "Carbon Neutral Environmentally Friendly A.I."
- bogzz 1mo ago
  "Miscreants" conjures in my mind an image of little British boys with dirty feet in Industrial Revolution era attire.
  - simonh 1mo ago
    Those cheeky chappies from Vodkaland with their Polonium water and Novichok perfume don't half get up to some jolly old japes!
- unglaublich 1mo ago
  Well, gas and oil plants are actively emitting pollutants that kill thousands. And nuclear still is the safest energy sort available.
  - testing22321 1mo ago
    > And nuclear still is the safest energy sort available. Surely solar is orders of magnitude safer.
    - georgefrowny 1mo ago
      Solar and nuclear are comparable: 0.02 vs 0.03 deaths/TWh (https://ourworldindata.org/grapher/death-rates-from-energy-production-per-twh https://ourworldindata.org/grapher/death-rates-from-energy-p...) Depending on what kind of solar, it can have quite a high death/TWh ratio because people fall off roofs while installing them. As a ratio is far better now that so much new solar is ground level solar farms and not installed by amateurs or professionals who have a van, a ladder and watched a YouTube video that one time. Some older estimates based, I think, on generic roofing accident rates, were up to 0.44 deaths/TWh. Wind is more dangerous than nuclear (0.04), I guess also from falls and accidents during construction and maintenance. Edit: All are incredibly safe compared to the next worst, hydro (1.3, or 30 times worse than wind).
jauntywundrkind 1mo ago
They're all ridiculously fuel inefficient and we're going to have to figure out how to dispose of thousands or tens of thousands of these reactors. Aside from that one that starts pre buried, where the plan is to just leave a spent nuclear reactor buried in a hole. A cost that will almost certainly be externalized to the taxpayers. The promise here is the rich fleecing the average citizen. Getting downvoted wicked hard super fast. But how else are we supposed to see this? How else do we citizens of the world interpret this? The fuel efficiency is a fact. The nuclear clean up has been a problem every single time.
- wing-_-nuts 1mo ago
  'Fuel efficiency' is not the bottle neck to getting more clean energy on the grid, scale is. Waste? grind it up, vitrify it, bury it in an abandoned coal mine or something. People get more radioactivity from a coal power plant than they will ever get from properly handled nuclear waste.
  - pfdietz 1mo ago
    It sure is. If the world were nuclear powered (all energy, not just grid) with burner reactors, estimates of uranium resources (not reserves) at up to 3x the current price would last about five years. A fully nuclear world needs to use nuclear fuel efficiently, which means breeder reactors.
    - wing-_-nuts 1mo ago
      ...and that's not a scenario that anyone is talking about employing with nuclear. We need enough for baseline load. Being able to build small modular reactors would give us scale that would help cut through the regulatory cost. By the time this crop of current reactors need to be decommissioned, we'd probably have dirt cheap grid storage figured out and could move away from them, but in the mean time, we need all the zero carbon energy we can get.
      - pfdietz 1mo ago
beardyw 1mo ago
"a supplement produced with financial support from Oklo Inc" "Oklo Corp. Logo Oklo is designing and deploying advanced fission power plants to provide clean, reliable, affordable energy"
ck2 1mo ago
there is just one problem like everything else with the current US administration they deregulated nuclear safety * https://www.npr.org/2026/01/28/nx-s1-5677187/nuclear-safety-rules-rewritten-trump https://www.npr.org/2026/01/28/nx-s1-5677187/nuclear-safety-... * https://www.npr.org/2026/08/27/nx-s1-5920368/nrc-nuclear-radiation-safety-rules-alara-update https://www.npr.org/2026/08/27/nx-s1-5920368/nrc-nuclear-rad... any other administration even Republican I'd be willing to listen to why this administration will happily kill thousands or give them cancer if it means another million dollars in their pockets there is only one kind of nuclear reactor that should be built anymore and that is Thorium reactors, they "fail safe" (or at least safer) * https://www.youtube.com/watch?v=ElulEJruhRQ https://www.youtube.com/watch?v=ElulEJruhRQ
- DanTheManPR 1mo ago
  Nuclear regulation could genuinely do with a lot of reforms that would streamline the process without appreciably impacting safety. Everyone would benefit. And that's the huge problem with the administration's breaking of trust and naked corruption: we as a lay people, what should we think if they come out with a bunch of proposals eliminate a bunch of commercial licensing requirement and lowering radiation safety standards? Is that because the old rules are genuinely archaic and not serving their purpose... or because Trump's family and donors are personally financially invested in the very companies mentioned in this article.
testing22321 1mo ago
I wish the article had more details on the cost to build these reactors, the cost to operate, refuel, dispose of fuel and then decommission. Details about how long they’re expected to operate, and how much power they will generate in their lifetime. Then we could get a projected cost per kWh for the power they will generate. I ask because the last reactors the US brought online took so long to build and cost so much they caused the cost of power to go up. This seems unworkable when solar is already causing power to be free (Australia), and gets cheaper by the day.
- zdragnar 1mo ago
  There's two reasons they take so long: large plants need to be redesigned as conditions on the site develop (soil type unexpectedly changes as excavation occurs) or regulations change during the process, and the second reason is that there's basically no nuclear construction industry. The benefit of an SMR is that it can theoretically be built largely off-site without the same risk that larger plants have wrt needing to customize everything. That allows construction companies to centralize and reuse talent and suppliers rather than needing to drag them all over the country or subcontracting to people more accustomed to building offices. In areas like where I live, there's weeks or more of time in winter where every day is overcast, short, and has little wind. To go completely renewable, we would need to pay southern regions to overproduce by triple digit percentages of their needs and then send the energy to us by HVDC that don't exist yet either. A bad ice storm or tornado could leave millions without any power at all at the most dangerous time of the year to not have electricity. It's doable, but we are a long way off and if SMR miraculously hits the right numbers, it'd be a better fit for us. Until then, we'll keep burning gas supplemented with solar.
hwillis 1mo ago
And a contrasting article from IEEE: https://spectrum.ieee.org/the-forgotten-history-of-small-nuclear-reactors https://spectrum.ieee.org/the-forgotten-history-of-small-nuc... > Samuel B. Morris, the general manager and chief engineer of Los Angeles’s Department of Water and Power, traveled all the way to Geneva in 1955 to attend the first International Conference on the Peaceful Uses of Atomic Energy. There, he made a case for small reactors, arguing that because the “number of small units…is many times the number of large units,” there could be “economy in development and repetitive manufacture” of the small units. > But nothing in the history of small nuclear reactors suggests that they would be more economical than full-size ones. In fact, the record is pretty clear: Without exception, small reactors cost too much for the little electricity they produced, the result of both their low output and their poor performance. For me, SMRs don't pass the smell test. Buying one big plot of land for a reactor, building one power interconnect, having a localized water impact is way easier and cheaper than many. Even if its cheaper to build small reactor vessels, MANY of the other costs become more expensive in larger numbers. Costs that you can ignore while you're just building a prototype. If it's so much cheaper to build multiple small reactors, just build one big plant with 24 small reactors. Thing is the nuclear reactor part is only 10-15% of the plants full cost: https://world-nuclear.org/information-library/economic-aspects/economics-of-nuclear-power https://world-nuclear.org/information-library/economic-aspec...
- tastyfreeze 1mo ago
  SMR proposals still use one plot of land. The plant is just built to house multiple reactors.
- arpinum 1mo ago
  SMR is driven by funding, insurance, and regulation. China doesn't have these issues and builds conventional at a great price. China is building 37 reactors, only 4-5 are SMR-type units, and are larger at 600MW. The rest are standard PWR, and the 40+ in planning are dominating by standard PWR. Regulatory risk is too high, building too infrequent to understand costs, funding for first-of-its-kind is too hard for nuclear in most countries. SMR makes it fundable. New designs give the hope that regulatory burdens can be lowered.
comrade1234 1mo ago
Seems like you'd end up with even more waste in the end. For example, the navy's nuclear reactor graveyard: https://interestingengineering.com/military/trench-94-the-eerie-final-resting-place-of-us-navys-nuclear-submarines https://interestingengineering.com/military/trench-94-the-ee... You could probably just sink it all in the ocean near a subduction zone.
- pfdietz 1mo ago
  I wish this subduction zone idea would just die. It's dumb. Things move so slowly it wouldn't help, and subduction zones have large amounts of volatiles coming back up via mud volcanoes and, later, actual molten rock volcanoes. If you want to dispose of waste deep in the sea floor do it far away from subduction zones. Or just store it cheaply in dry casks and minimize the net present value of the cost of dealing with the waste.
  - bell-cot 1mo ago
    Short-term, subduction zones are deep, maximizing the difficulty for malicious actors trying to get their hands on the waste. The subduction itself is more a marketing feature, for folks who oppose putting the waste anywhere on the surface of the Earth. Longer-term - it's mid-ocean ridges, not subduction zones, where you find all the volatiles and volcanoes. Yes, millions of years in the future, some micro-percentage of the subducted material will re-emerge, hundreds of miles away, via volcanoes. So will vastly more natural radioactivity, whether or not we dispose of nuclear waste in the subduction zone.
    - pfdietz 1mo ago
      > Longer-term - it's mid-ocean ridges, not subduction zones, where you find all the volatiles and volcanoes. That's simply not true. Yes, there are volcanoes at mid-ocean ridges, but subduction zones also have plenty of activity. https://en.wikipedia.org/wiki/Mud_volcano https://en.wikipedia.org/wiki/Mud_volcano "There are 10 active mud volcanoes in the Izu–Bonin–Mariana Arc which can be found along a north to south trend, parallel to the Mariana trench.[43] The material erupted at these mud volcanoes consists primarily of blue and green serpentinite mud which contains fresh and serpentinized peridotite material from the subduction channel. Fluid from the descending Pacific Plate is released by dehydration and alteration of rocks and sediment." https://en.wikipedia.org/wiki/Volcanic_arc https://en.wikipedia.org/wiki/Volcanic_arc (for description of how subduction zones create magmatic volcanoes) Subducted material is very wet, and as it descends the volatiles ascend to melt the rock above, creating magma (water reduces the melting point of rocks just like it reduces the melting point of sugar.)
DanTheManPR 1mo ago
A lot of people are betting serious money that they will cheaper, more flexible, faster to build, and safer. Including me - I'm working in the industry, and I think they might very well be future backbone of energy production. But there's a real possibility when all this shakes out that SMR's only advantage will be their flexibility. And that might be enough. A major issue with gigawatt scale nuclear is that it's frankly too big for most markets. Only very large electric markets can can easily digest a new always-on 1000 megawatts of electricity, and you need to be building multiple plants at a time for this all to be economical. That's why the nuclear power rollout of the 60s through 80s worked, and why China and to a lesser extent India's nuclear industry is thriving presently. With an SMRs smaller scale, there are just way more available projects where nuclear is feasible, and so a more consistent workload can keep everyone employed and subcontractor's backlogs filled. The flexibility in scaling lets you reclaim the benefits of having an experienced workforce and that knows how to build nuclear power plants, something we lost in the west when we stopped building them.
- fulafel 1mo ago
  What % of global electricity production is in too small markets? Seems to be working well in EU at least, markets and grids being multinational. I'd guess many places in Africa could be potential markets that have underdeveloped grids but growing economies and populations. Hence the SMR industry in South Africa since the 90s I guess.
  - DanTheManPR 1mo ago
    We're looking specifically at new power plant builds. The majority of that is in Asia, with China and India being the bulk of it. But there is a lot of Asia outside of those two, and in particular Southeast Asia has a lot of potential. There is a lot of long distance transmission line connectivity already, and more planned, but you still want to product power close to where it's used so as to avoid losses in transmission. And the finances for a smaller country are just more straightforward if you're not spending multiple billions of dollars on one giant plant. The next big market is actually replacement plants in the USA and Europe. Electricity generation may have peaked there, but much of the generating capacity is decades old and needs replacement. There are a lot of smaller facilities that are not gigawatt-scale that need to shut down, and it's easier to plug that gap with SMRs. South and Central America are small markets, but they won't be ignored. There is a lot of complexity here with the inter-national hydro projects and broken up grids, so I'm sure some countries will look into SMRs. Africa unfortunately just doesn't factor in except as a long-term possibility for growth. It's only 3% of electricity generation now, and its share will probably fall as Asia electrifies. This is all worst-case scenario where SMRs are less financially competitive than current gigawatt-scale designs. If SMRs do actually succeed in being cheap assembly-line reactors, then all bets are off and the industry will experience explosive growth.
neuroelectron 1mo ago
This is a great temporary solution to continue developing AI up to a reliable state, then the ownership can be transferred to a particular state that is major global presence in cybersecurity, semiconductor design, and tech innovation, who is already well positioned with key stakeholders in most if not all American tech companies with strong grantees in government support. Major technology companies have signed strategic agreements for SMR development, but regulatory approvals and supply-chain scaling place widespread commercial deployment in the late 2020s through the 2030s. Now that we are in astronomical debt, it's our responsibility to turn our nation into a wasteland in order to provide this particular nation a scalable, full spectrum and robust AI defense solution that will allow them to achieve their geopolitical goals safely without fear of reprisal while they continue to expand their influence in tech and the global economy, hopefully culminating in extracting taxes on ships going through key trade canals near their borders and beyond.
ZeroGravitas 1mo ago
Donald Trump does a lot of stupid evil stuff to further fossil fuels but getting all the tech nerds excited about even more expensive nuclear power is actually evil genius.
- actionfromafar 1mo ago
  Yes. They are apparently scrubbing the truth but archive.org still has it. https://web.archive.org/web/20250507123042/https://docs.nrel.gov/docs/fy24osti/85879.pdf https://web.archive.org/web/20250507123042/https://docs.nrel...
  - wing-_-nuts 1mo ago
    I'm sorry, if you're gonna link to a 111 page pdf, please at least quote the area of interest?
bell-cot 1mo ago
Nuclear power's biggest problem is that it attracted, even back in the 1940's, a figurative army of techno-utopians - whose pie-in-the-sky promises of electric power too cheap meter, flying cars, and better-than-Santa's-sleigh safety were not quickly and loudly contradicted by people who knew better. Probably didn't help that many of those keeping quiet had obvious short-term interests in promoting "nuclear everything". Even as various accidents, leaking waste dumps, and regular warnings of deadly communist mushroom clouds made it damned obvious to the general public that they were being systematically lied to. Sadly, the pro-nuclear camp is still far too influenced by utopian and partisan considerations. Yes, it'd be nice to see competently-done SMR's in regular use, for the use cases where they make sense. But if I was a policy maker with finite political capital and resources, I'd probably be winding down nuclear power - both to show the public that I wasn't too gullible to trust, and to show advocates for other technologies that lies and delusions would be carry harsh penalties.
- DennisP 1mo ago
  Sure, and none of solar's advocates are utopian at all.
  - wing-_-nuts 1mo ago
    I don't think solar even needs advocates at this point. Battery backed solar should win on pure economics.
  - bell-cot 1mo ago
    The general public doesn't care about utopian-measuring contests between different groups of zealots. They want cheap electricity on demand, safety, and a sense of control. Solar does a pretty good job of offering that. Nuclear? Nope.
    - DennisP 1mo ago
      I agree that the utopian tendencies of various groups are irrelevant. So I'm not sure why you brought it up.
samizdis 1mo ago
Hmmmnnnn. I remember getting excited reading a Wired article "Let a thousand reactors bloom" [0] - but that was back in 2004. I'm still waiting for a "pizza-safe" pebble-bed reactor. [0] https://www.wired.com/2004/09/china-5/ https://www.wired.com/2004/09/china-5/
- roryirvine 1mo ago
  This Nature article dubs TRISO fuel as "accident-tolerant", which is just as well given the lamentable history of it in actual use. https://en.wikipedia.org/wiki/AVR_reactor https://en.wikipedia.org/wiki/AVR_reactor for instance, which suffered so many accidents that it was known as the "Shipwreck". It ended up with TRISO pebbles getting stuck in the reactor vessel, the primary circuit being hopelessly contaminated with fission products, and is now impossible to safely decommission using current technology. It seems to me working SMRs really would be valuable, particularly for off-grid applications or where process heat is needed alongside electricity generation. But as someone who was, like you, taken in by the pebble bed hype last time around, I've now learned to be much more sceptical about new nuclear technologies until they've actually been proven in practice.
  - pfdietz 1mo ago
    TRISO is also more expensive, both in fabrication and disposal. It looks to me like another case of nuclear mis-optimizing for the wrong metric (safety vs. cost).
deleted 1mo ago
[deleted]
CrzyLngPwd 1mo ago
Literaly, designed for datacenters
marcosdumay 1mo ago
Just worth remembering that the cost/W of steam generators decrease quickly (almost linearly) with size up to ~1GW. What in reverse also means it increases quickly with reduced size, down to the point you can order them 3D printed on the internet (what is around a couple of kW). And also that steam generators alone have a really hard time competing with solar nowadays.
arjie 1mo ago
It's really a pity that we missed the boat on large nuclear reactors. So much more power would enable so many use-cases and cheap electricity would have enabled us to have much less gas heating. Massive damage to the climate caused by misguided regulation. I tried to write to deregulation.gov on reducing the fund allocation required for fission reactor cleanup but c'est la vie. Death by a thousand cuts and then a few big rocks, I suppose. We lost half a century, but so it goes. Now we should be able to do large-scale solar and wind, and if it weren't for the Burning Man people we could have geothermal too, but we'll get there.
- unclad5968 1mo ago
  What does burning man have to do with geothermal?
  - arjie 1mo ago
    They blocked geothermal drilling in the desert. After multiple years of blocking it with use of environmental law they finally managed to preserve it as a conservation area for sustainable tourism: > Organizers of the Burning Man festival in northwest Nevada have reached a settlement with a geothermal energy developer that cancels an exploratory drilling project that some feared would ruin the ambiance of the counter-culture event. https://www.eenews.net/articles/burning-man-to-buy-back-geothermal-leases-drop-blm-lawsuit/ https://www.eenews.net/articles/burning-man-to-buy-back-geot...
    - consumer451 1mo ago
      That's so weird. I have never seen more fossil fuels and wood burned just for art, than at burning man. They should have had an artist work with them to make whatever the exploration gear was, look like a permanent installation. It might not have even required actual changes, just a label.
  - sojournerc 1mo ago
    In addition to the sibling comment, I'll say that environmentalists have opposed nuclear energy for half a century, despite it being far better than coal or ng in terms of emissions. I'd say that the venn diagram intersection of burners and opposition to nuclear is significant.
Animats 1mo ago
How are the fusion startups coming along? There are at least 21 of them.[1] The top 3, by funding. These all have more than a billion dollars. Commonwealth Fusion Systems. The MIT people. This is a tokamak with better magnets. The magnet insight is that if you put a superconductor and a regular conductor in parallel, all the current flows through the superconductor. So you can plate a superconducting material on stainless steel tape, using stainless steel as an insulator. Winding a magnet out of stainless steel tape works fine. They demoed that back in 2021. But no fusion yet. Well funded, big operation, around 1000 people. Helion Energy. This is a strange magneto-inertial fusion system. It's vaguely like a free-piston internal combustion engine generator, except that the piston is a plasma. After seven rounds of increasingly large prototypes, they can get D-T fusion, but it's not self-sustaining, nor do they get power out. Prototypes have thus far underperformed claims. Around 500 people. TAE. Recently merged with Trump Media. Really. There are quite a few others. Many are working on some kind of pulsed fusion, like the Livermore National Ignition Facility. This is known to create fusion, but is hard to turn into a useful power source. They can get to a non-useful fusion demo by pumping a lot of energy into a small space, so it looks like progress. On the continuous fusion front, several startups are trying to revive 1950s Stellarator technology. For a few years back then, fusion energy looked close. Anyone have expertise in this area? Are any of these going to work? Or is the product the stock? [1] https://www.energystartups.org/top/fusion-energy/USA/ https://www.energystartups.org/top/fusion-energy/USA/
- fpoling 1mo ago
  Helion most likely would not work. Even their own optimistic modeling gives very thin margins and even they completely ignore radiation damage to equipment. Commonwealth and other tokamak designs are too optimistic as well. We do not know how instability in plasma will behave in production volumes. Stellarator-based designs at least do not have big ifs, but they are way further and even they assume that radiation damage from neutrons will be manageable. And all of this is ignoring costs. Outside of niche applications it is very hard to sea how fusion even if it works can compete with solar plus storage.
emsign 1mo ago
The future will be solar. Especially in underdeveloped regions without a centralized power grid, solar makes the most sense. And even in developed countries having solar panels on your roof and a battery in your cellar is the most cost effective way of getting all your electricity needs.
thinkcontext 1mo ago
There are no working SMR's ready to be deployed in the West. The company (NuScale) that was furthest along had its flagship project die after cost estimates ballooned. Its other project was a crypto scam. Whether any of these companies work out and make it to serial production is very speculative.
- agarwaen163 1mo ago
  Are you forgetting Valar Atomics exists buddy? Or Aalo, or Antares or Radiant?
  - thinkcontext 1mo ago
    None of those are ready to deploy, they are in experimental testing. They have several phases of that still to go before they can get a license.
- p2detar 1mo ago
  The SMR in Darlington, Canada is already in construction. https://www.world-nuclear-news.org/articles/darlington-smr-nuclear-project-foundation-module-milestone https://www.world-nuclear-news.org/articles/darlington-smr-n...
odyssey7 1mo ago
> Hermes 1, by contrast, is fuelled by tristructural isotopic (TRISO) pebbles — poppy-seed-sized particles of uranium, encased in a carbon-ceramic shell. What writing
danra 1mo ago
I've always advocated for smaller atomic refactors. ...oh. Never mind.
coder0x 1mo ago
[flagged]
thelastgallon 1mo ago
Nuclear, while exorbitant, is necessary for security. See North Korea vs Iran/Venezuela. Nuclear scientists, supply chains, and a trained workforce takes decades to develop. Excess power production can be used to smelt aluminum. You can always have strategic excess supply of materials that can use flexible supply.
vrighter 1mo ago
large scale is cheaper more economical anywhere else. I don't believe making reactors smaller would work differently than anything else.

159 points by sohkamyung 1mo ago

hvb2 1mo ago

> but SMRs should be cheaper and easier to construct. The word should is doing some real heavy lifting there. Especially given the subject. I guess we'll know in 2030 when one should come online.

HPsquared 1mo ago
We should know by then, at least.
ViewTrick1002 1mo ago
It just stupidly expensive if it is completed on time and budget. To make the figure at least palatable for public funding the project assumes enormous learning effects for subsequent reactors.
agarwaen163 1mo ago
Except Valar already did it earlier this year.
- hvb2 1mo ago
  Not sure what you're referring to but in June they achieved criticality in a demo. While a good milestone that's not at all a functioning reactor connected to the grid. Let alone anything like a repeatable consistent production of said reactor.

soco 1mo ago

With solar and batteries getting cheaper and cheaper, is this still a topic? Or at least for the time being until that "cheaper" gets cheaper enough?

petcat 1mo ago
> In March 2025, the US Department of Energy (DoE) announced US $900 million in grants to support the deployment of SMRs. One year later, the European Commission said it would invest up to €200 million (US $228 million) in the construction of SMRs. Yes, it does seem to still be a topic.
- jauntywundrkind 1mo ago
  And the US is spending vastly more to make sure renewables and solar don't get built. https://www.washingtonpost.com/business/2026/08/27/how-wind-projects-got-replaced-by-900-million-payday-trump-donors-firm/ https://www.washingtonpost.com/business/2026/08/27/how-wind-...
  - pfdietz 1mo ago
    > making sure If this is the goal, they're failing spectacularly.
RivieraKid 1mo ago
Solar + battery is very land inefficient, that's basically the main argument. Edit: Per ChatGPT's calculation, nuclear is significantly cheaper than solar + battery in my country (Czech Republic) if we're talking about adding new reactors to existing power plants.
- actionfromafar 1mo ago
  But batteries can be very distributed and stabilize and prop up the grid in ways a huge plant can't without building out distribution. (Situation dependent of course.)
- pfdietz 1mo ago
  Land is cheap. Even in Europe, the cost of land onto which renewables are put is small compared to the cost of the renewable energy equipment itself. Here in the US, it's common for the land to be just a few percent of the project cost.

hn_submit 1mo ago

Although generally safe these reactors aren't totally safe. I'm concerned lax physical security will allow miscreants to blow them up and spread nuclear materials over a wide area. The ensuing panic would totally destroy any goodwill nuclear power has gained over the last 20 years or so. I'm also concerned these things will mostly be used by Big Tech for their A.I. data-centers playing the Good Samaritan with their claims of "Carbon Neutral Environmentally Friendly A.I."

bogzz 1mo ago
"Miscreants" conjures in my mind an image of little British boys with dirty feet in Industrial Revolution era attire.
- simonh 1mo ago
  Those cheeky chappies from Vodkaland with their Polonium water and Novichok perfume don't half get up to some jolly old japes!
unglaublich 1mo ago
Well, gas and oil plants are actively emitting pollutants that kill thousands. And nuclear still is the safest energy sort available.
- testing22321 1mo ago
  > And nuclear still is the safest energy sort available. Surely solar is orders of magnitude safer.
  - georgefrowny 1mo ago
    Solar and nuclear are comparable: 0.02 vs 0.03 deaths/TWh (https://ourworldindata.org/grapher/death-rates-from-energy-production-per-twh https://ourworldindata.org/grapher/death-rates-from-energy-p...) Depending on what kind of solar, it can have quite a high death/TWh ratio because people fall off roofs while installing them. As a ratio is far better now that so much new solar is ground level solar farms and not installed by amateurs or professionals who have a van, a ladder and watched a YouTube video that one time. Some older estimates based, I think, on generic roofing accident rates, were up to 0.44 deaths/TWh. Wind is more dangerous than nuclear (0.04), I guess also from falls and accidents during construction and maintenance. Edit: All are incredibly safe compared to the next worst, hydro (1.3, or 30 times worse than wind).

jauntywundrkind 1mo ago

They're all ridiculously fuel inefficient and we're going to have to figure out how to dispose of thousands or tens of thousands of these reactors. Aside from that one that starts pre buried, where the plan is to just leave a spent nuclear reactor buried in a hole. A cost that will almost certainly be externalized to the taxpayers. The promise here is the rich fleecing the average citizen. Getting downvoted wicked hard super fast. But how else are we supposed to see this? How else do we citizens of the world interpret this? The fuel efficiency is a fact. The nuclear clean up has been a problem every single time.

wing-_-nuts 1mo ago
'Fuel efficiency' is not the bottle neck to getting more clean energy on the grid, scale is. Waste? grind it up, vitrify it, bury it in an abandoned coal mine or something. People get more radioactivity from a coal power plant than they will ever get from properly handled nuclear waste.
- pfdietz 1mo ago
  It sure is. If the world were nuclear powered (all energy, not just grid) with burner reactors, estimates of uranium resources (not reserves) at up to 3x the current price would last about five years. A fully nuclear world needs to use nuclear fuel efficiently, which means breeder reactors.
  - wing-_-nuts 1mo ago
    ...and that's not a scenario that anyone is talking about employing with nuclear. We need enough for baseline load. Being able to build small modular reactors would give us scale that would help cut through the regulatory cost. By the time this crop of current reactors need to be decommissioned, we'd probably have dirt cheap grid storage figured out and could move away from them, but in the mean time, we need all the zero carbon energy we can get.
    - pfdietz 1mo ago

beardyw 1mo ago

"a supplement produced with financial support from Oklo Inc" "Oklo Corp. Logo Oklo is designing and deploying advanced fission power plants to provide clean, reliable, affordable energy"

ck2 1mo ago

there is just one problem like everything else with the current US administration they deregulated nuclear safety * https://www.npr.org/2026/01/28/nx-s1-5677187/nuclear-safety-rules-rewritten-trump https://www.npr.org/2026/01/28/nx-s1-5677187/nuclear-safety-... * https://www.npr.org/2026/08/27/nx-s1-5920368/nrc-nuclear-radiation-safety-rules-alara-update https://www.npr.org/2026/08/27/nx-s1-5920368/nrc-nuclear-rad... any other administration even Republican I'd be willing to listen to why this administration will happily kill thousands or give them cancer if it means another million dollars in their pockets there is only one kind of nuclear reactor that should be built anymore and that is Thorium reactors, they "fail safe" (or at least safer) * https://www.youtube.com/watch?v=ElulEJruhRQ https://www.youtube.com/watch?v=ElulEJruhRQ

DanTheManPR 1mo ago
Nuclear regulation could genuinely do with a lot of reforms that would streamline the process without appreciably impacting safety. Everyone would benefit. And that's the huge problem with the administration's breaking of trust and naked corruption: we as a lay people, what should we think if they come out with a bunch of proposals eliminate a bunch of commercial licensing requirement and lowering radiation safety standards? Is that because the old rules are genuinely archaic and not serving their purpose... or because Trump's family and donors are personally financially invested in the very companies mentioned in this article.

testing22321 1mo ago

I wish the article had more details on the cost to build these reactors, the cost to operate, refuel, dispose of fuel and then decommission. Details about how long they’re expected to operate, and how much power they will generate in their lifetime. Then we could get a projected cost per kWh for the power they will generate. I ask because the last reactors the US brought online took so long to build and cost so much they caused the cost of power to go up. This seems unworkable when solar is already causing power to be free (Australia), and gets cheaper by the day.

zdragnar 1mo ago
There's two reasons they take so long: large plants need to be redesigned as conditions on the site develop (soil type unexpectedly changes as excavation occurs) or regulations change during the process, and the second reason is that there's basically no nuclear construction industry. The benefit of an SMR is that it can theoretically be built largely off-site without the same risk that larger plants have wrt needing to customize everything. That allows construction companies to centralize and reuse talent and suppliers rather than needing to drag them all over the country or subcontracting to people more accustomed to building offices. In areas like where I live, there's weeks or more of time in winter where every day is overcast, short, and has little wind. To go completely renewable, we would need to pay southern regions to overproduce by triple digit percentages of their needs and then send the energy to us by HVDC that don't exist yet either. A bad ice storm or tornado could leave millions without any power at all at the most dangerous time of the year to not have electricity. It's doable, but we are a long way off and if SMR miraculously hits the right numbers, it'd be a better fit for us. Until then, we'll keep burning gas supplemented with solar.

hwillis 1mo ago

And a contrasting article from IEEE: https://spectrum.ieee.org/the-forgotten-history-of-small-nuclear-reactors https://spectrum.ieee.org/the-forgotten-history-of-small-nuc... > Samuel B. Morris, the general manager and chief engineer of Los Angeles’s Department of Water and Power, traveled all the way to Geneva in 1955 to attend the first International Conference on the Peaceful Uses of Atomic Energy. There, he made a case for small reactors, arguing that because the “number of small units…is many times the number of large units,” there could be “economy in development and repetitive manufacture” of the small units. > But nothing in the history of small nuclear reactors suggests that they would be more economical than full-size ones. In fact, the record is pretty clear: Without exception, small reactors cost too much for the little electricity they produced, the result of both their low output and their poor performance. For me, SMRs don't pass the smell test. Buying one big plot of land for a reactor, building one power interconnect, having a localized water impact is way easier and cheaper than many. Even if its cheaper to build small reactor vessels, MANY of the other costs become more expensive in larger numbers. Costs that you can ignore while you're just building a prototype. If it's so much cheaper to build multiple small reactors, just build one big plant with 24 small reactors. Thing is the nuclear reactor part is only 10-15% of the plants full cost: https://world-nuclear.org/information-library/economic-aspects/economics-of-nuclear-power https://world-nuclear.org/information-library/economic-aspec...

tastyfreeze 1mo ago
SMR proposals still use one plot of land. The plant is just built to house multiple reactors.
arpinum 1mo ago
SMR is driven by funding, insurance, and regulation. China doesn't have these issues and builds conventional at a great price. China is building 37 reactors, only 4-5 are SMR-type units, and are larger at 600MW. The rest are standard PWR, and the 40+ in planning are dominating by standard PWR. Regulatory risk is too high, building too infrequent to understand costs, funding for first-of-its-kind is too hard for nuclear in most countries. SMR makes it fundable. New designs give the hope that regulatory burdens can be lowered.

comrade1234 1mo ago

Seems like you'd end up with even more waste in the end. For example, the navy's nuclear reactor graveyard: https://interestingengineering.com/military/trench-94-the-eerie-final-resting-place-of-us-navys-nuclear-submarines https://interestingengineering.com/military/trench-94-the-ee... You could probably just sink it all in the ocean near a subduction zone.

pfdietz 1mo ago
I wish this subduction zone idea would just die. It's dumb. Things move so slowly it wouldn't help, and subduction zones have large amounts of volatiles coming back up via mud volcanoes and, later, actual molten rock volcanoes. If you want to dispose of waste deep in the sea floor do it far away from subduction zones. Or just store it cheaply in dry casks and minimize the net present value of the cost of dealing with the waste.
- bell-cot 1mo ago
  Short-term, subduction zones are deep, maximizing the difficulty for malicious actors trying to get their hands on the waste. The subduction itself is more a marketing feature, for folks who oppose putting the waste anywhere on the surface of the Earth. Longer-term - it's mid-ocean ridges, not subduction zones, where you find all the volatiles and volcanoes. Yes, millions of years in the future, some micro-percentage of the subducted material will re-emerge, hundreds of miles away, via volcanoes. So will vastly more natural radioactivity, whether or not we dispose of nuclear waste in the subduction zone.
  - pfdietz 1mo ago
    > Longer-term - it's mid-ocean ridges, not subduction zones, where you find all the volatiles and volcanoes. That's simply not true. Yes, there are volcanoes at mid-ocean ridges, but subduction zones also have plenty of activity. https://en.wikipedia.org/wiki/Mud_volcano https://en.wikipedia.org/wiki/Mud_volcano "There are 10 active mud volcanoes in the Izu–Bonin–Mariana Arc which can be found along a north to south trend, parallel to the Mariana trench.[43] The material erupted at these mud volcanoes consists primarily of blue and green serpentinite mud which contains fresh and serpentinized peridotite material from the subduction channel. Fluid from the descending Pacific Plate is released by dehydration and alteration of rocks and sediment." https://en.wikipedia.org/wiki/Volcanic_arc https://en.wikipedia.org/wiki/Volcanic_arc (for description of how subduction zones create magmatic volcanoes) Subducted material is very wet, and as it descends the volatiles ascend to melt the rock above, creating magma (water reduces the melting point of rocks just like it reduces the melting point of sugar.)

DanTheManPR 1mo ago

A lot of people are betting serious money that they will cheaper, more flexible, faster to build, and safer. Including me - I'm working in the industry, and I think they might very well be future backbone of energy production. But there's a real possibility when all this shakes out that SMR's only advantage will be their flexibility. And that might be enough. A major issue with gigawatt scale nuclear is that it's frankly too big for most markets. Only very large electric markets can can easily digest a new always-on 1000 megawatts of electricity, and you need to be building multiple plants at a time for this all to be economical. That's why the nuclear power rollout of the 60s through 80s worked, and why China and to a lesser extent India's nuclear industry is thriving presently. With an SMRs smaller scale, there are just way more available projects where nuclear is feasible, and so a more consistent workload can keep everyone employed and subcontractor's backlogs filled. The flexibility in scaling lets you reclaim the benefits of having an experienced workforce and that knows how to build nuclear power plants, something we lost in the west when we stopped building them.

fulafel 1mo ago
What % of global electricity production is in too small markets? Seems to be working well in EU at least, markets and grids being multinational. I'd guess many places in Africa could be potential markets that have underdeveloped grids but growing economies and populations. Hence the SMR industry in South Africa since the 90s I guess.
- DanTheManPR 1mo ago
  We're looking specifically at new power plant builds. The majority of that is in Asia, with China and India being the bulk of it. But there is a lot of Asia outside of those two, and in particular Southeast Asia has a lot of potential. There is a lot of long distance transmission line connectivity already, and more planned, but you still want to product power close to where it's used so as to avoid losses in transmission. And the finances for a smaller country are just more straightforward if you're not spending multiple billions of dollars on one giant plant. The next big market is actually replacement plants in the USA and Europe. Electricity generation may have peaked there, but much of the generating capacity is decades old and needs replacement. There are a lot of smaller facilities that are not gigawatt-scale that need to shut down, and it's easier to plug that gap with SMRs. South and Central America are small markets, but they won't be ignored. There is a lot of complexity here with the inter-national hydro projects and broken up grids, so I'm sure some countries will look into SMRs. Africa unfortunately just doesn't factor in except as a long-term possibility for growth. It's only 3% of electricity generation now, and its share will probably fall as Asia electrifies. This is all worst-case scenario where SMRs are less financially competitive than current gigawatt-scale designs. If SMRs do actually succeed in being cheap assembly-line reactors, then all bets are off and the industry will experience explosive growth.

neuroelectron 1mo ago

This is a great temporary solution to continue developing AI up to a reliable state, then the ownership can be transferred to a particular state that is major global presence in cybersecurity, semiconductor design, and tech innovation, who is already well positioned with key stakeholders in most if not all American tech companies with strong grantees in government support. Major technology companies have signed strategic agreements for SMR development, but regulatory approvals and supply-chain scaling place widespread commercial deployment in the late 2020s through the 2030s. Now that we are in astronomical debt, it's our responsibility to turn our nation into a wasteland in order to provide this particular nation a scalable, full spectrum and robust AI defense solution that will allow them to achieve their geopolitical goals safely without fear of reprisal while they continue to expand their influence in tech and the global economy, hopefully culminating in extracting taxes on ships going through key trade canals near their borders and beyond.

ZeroGravitas 1mo ago

Donald Trump does a lot of stupid evil stuff to further fossil fuels but getting all the tech nerds excited about even more expensive nuclear power is actually evil genius.

actionfromafar 1mo ago
Yes. They are apparently scrubbing the truth but archive.org still has it. https://web.archive.org/web/20250507123042/https://docs.nrel.gov/docs/fy24osti/85879.pdf https://web.archive.org/web/20250507123042/https://docs.nrel...
- wing-_-nuts 1mo ago
  I'm sorry, if you're gonna link to a 111 page pdf, please at least quote the area of interest?

bell-cot 1mo ago

Nuclear power's biggest problem is that it attracted, even back in the 1940's, a figurative army of techno-utopians - whose pie-in-the-sky promises of electric power too cheap meter, flying cars, and better-than-Santa's-sleigh safety were not quickly and loudly contradicted by people who knew better. Probably didn't help that many of those keeping quiet had obvious short-term interests in promoting "nuclear everything". Even as various accidents, leaking waste dumps, and regular warnings of deadly communist mushroom clouds made it damned obvious to the general public that they were being systematically lied to. Sadly, the pro-nuclear camp is still far too influenced by utopian and partisan considerations. Yes, it'd be nice to see competently-done SMR's in regular use, for the use cases where they make sense. But if I was a policy maker with finite political capital and resources, I'd probably be winding down nuclear power - both to show the public that I wasn't too gullible to trust, and to show advocates for other technologies that lies and delusions would be carry harsh penalties.

DennisP 1mo ago
Sure, and none of solar's advocates are utopian at all.
- wing-_-nuts 1mo ago
  I don't think solar even needs advocates at this point. Battery backed solar should win on pure economics.
- bell-cot 1mo ago
  The general public doesn't care about utopian-measuring contests between different groups of zealots. They want cheap electricity on demand, safety, and a sense of control. Solar does a pretty good job of offering that. Nuclear? Nope.
  - DennisP 1mo ago
    I agree that the utopian tendencies of various groups are irrelevant. So I'm not sure why you brought it up.

samizdis 1mo ago

Hmmmnnnn. I remember getting excited reading a Wired article "Let a thousand reactors bloom" [0] - but that was back in 2004. I'm still waiting for a "pizza-safe" pebble-bed reactor. [0] https://www.wired.com/2004/09/china-5/ https://www.wired.com/2004/09/china-5/

roryirvine 1mo ago
This Nature article dubs TRISO fuel as "accident-tolerant", which is just as well given the lamentable history of it in actual use. https://en.wikipedia.org/wiki/AVR_reactor https://en.wikipedia.org/wiki/AVR_reactor for instance, which suffered so many accidents that it was known as the "Shipwreck". It ended up with TRISO pebbles getting stuck in the reactor vessel, the primary circuit being hopelessly contaminated with fission products, and is now impossible to safely decommission using current technology. It seems to me working SMRs really would be valuable, particularly for off-grid applications or where process heat is needed alongside electricity generation. But as someone who was, like you, taken in by the pebble bed hype last time around, I've now learned to be much more sceptical about new nuclear technologies until they've actually been proven in practice.
- pfdietz 1mo ago
  TRISO is also more expensive, both in fabrication and disposal. It looks to me like another case of nuclear mis-optimizing for the wrong metric (safety vs. cost).

deleted 1mo ago

[deleted]

CrzyLngPwd 1mo ago

Literaly, designed for datacenters

marcosdumay 1mo ago

Just worth remembering that the cost/W of steam generators decrease quickly (almost linearly) with size up to ~1GW. What in reverse also means it increases quickly with reduced size, down to the point you can order them 3D printed on the internet (what is around a couple of kW). And also that steam generators alone have a really hard time competing with solar nowadays.

arjie 1mo ago

It's really a pity that we missed the boat on large nuclear reactors. So much more power would enable so many use-cases and cheap electricity would have enabled us to have much less gas heating. Massive damage to the climate caused by misguided regulation. I tried to write to deregulation.gov on reducing the fund allocation required for fission reactor cleanup but c'est la vie. Death by a thousand cuts and then a few big rocks, I suppose. We lost half a century, but so it goes. Now we should be able to do large-scale solar and wind, and if it weren't for the Burning Man people we could have geothermal too, but we'll get there.

unclad5968 1mo ago
What does burning man have to do with geothermal?
- arjie 1mo ago
  They blocked geothermal drilling in the desert. After multiple years of blocking it with use of environmental law they finally managed to preserve it as a conservation area for sustainable tourism: > Organizers of the Burning Man festival in northwest Nevada have reached a settlement with a geothermal energy developer that cancels an exploratory drilling project that some feared would ruin the ambiance of the counter-culture event. https://www.eenews.net/articles/burning-man-to-buy-back-geothermal-leases-drop-blm-lawsuit/ https://www.eenews.net/articles/burning-man-to-buy-back-geot...
  - consumer451 1mo ago
    That's so weird. I have never seen more fossil fuels and wood burned just for art, than at burning man. They should have had an artist work with them to make whatever the exploration gear was, look like a permanent installation. It might not have even required actual changes, just a label.
- sojournerc 1mo ago
  In addition to the sibling comment, I'll say that environmentalists have opposed nuclear energy for half a century, despite it being far better than coal or ng in terms of emissions. I'd say that the venn diagram intersection of burners and opposition to nuclear is significant.

Animats 1mo ago

How are the fusion startups coming along? There are at least 21 of them.[1] The top 3, by funding. These all have more than a billion dollars. Commonwealth Fusion Systems. The MIT people. This is a tokamak with better magnets. The magnet insight is that if you put a superconductor and a regular conductor in parallel, all the current flows through the superconductor. So you can plate a superconducting material on stainless steel tape, using stainless steel as an insulator. Winding a magnet out of stainless steel tape works fine. They demoed that back in 2021. But no fusion yet. Well funded, big operation, around 1000 people. Helion Energy. This is a strange magneto-inertial fusion system. It's vaguely like a free-piston internal combustion engine generator, except that the piston is a plasma. After seven rounds of increasingly large prototypes, they can get D-T fusion, but it's not self-sustaining, nor do they get power out. Prototypes have thus far underperformed claims. Around 500 people. TAE. Recently merged with Trump Media. Really. There are quite a few others. Many are working on some kind of pulsed fusion, like the Livermore National Ignition Facility. This is known to create fusion, but is hard to turn into a useful power source. They can get to a non-useful fusion demo by pumping a lot of energy into a small space, so it looks like progress. On the continuous fusion front, several startups are trying to revive 1950s Stellarator technology. For a few years back then, fusion energy looked close. Anyone have expertise in this area? Are any of these going to work? Or is the product the stock? [1] https://www.energystartups.org/top/fusion-energy/USA/ https://www.energystartups.org/top/fusion-energy/USA/

fpoling 1mo ago
Helion most likely would not work. Even their own optimistic modeling gives very thin margins and even they completely ignore radiation damage to equipment. Commonwealth and other tokamak designs are too optimistic as well. We do not know how instability in plasma will behave in production volumes. Stellarator-based designs at least do not have big ifs, but they are way further and even they assume that radiation damage from neutrons will be manageable. And all of this is ignoring costs. Outside of niche applications it is very hard to sea how fusion even if it works can compete with solar plus storage.

emsign 1mo ago

The future will be solar. Especially in underdeveloped regions without a centralized power grid, solar makes the most sense. And even in developed countries having solar panels on your roof and a battery in your cellar is the most cost effective way of getting all your electricity needs.

thinkcontext 1mo ago

There are no working SMR's ready to be deployed in the West. The company (NuScale) that was furthest along had its flagship project die after cost estimates ballooned. Its other project was a crypto scam. Whether any of these companies work out and make it to serial production is very speculative.

agarwaen163 1mo ago
Are you forgetting Valar Atomics exists buddy? Or Aalo, or Antares or Radiant?
- thinkcontext 1mo ago
  None of those are ready to deploy, they are in experimental testing. They have several phases of that still to go before they can get a license.
p2detar 1mo ago
The SMR in Darlington, Canada is already in construction. https://www.world-nuclear-news.org/articles/darlington-smr-nuclear-project-foundation-module-milestone https://www.world-nuclear-news.org/articles/darlington-smr-n...

odyssey7 1mo ago

> Hermes 1, by contrast, is fuelled by tristructural isotopic (TRISO) pebbles — poppy-seed-sized particles of uranium, encased in a carbon-ceramic shell. What writing

danra 1mo ago

I've always advocated for smaller atomic refactors. ...oh. Never mind.

coder0x 1mo ago

[flagged]

thelastgallon 1mo ago

Nuclear, while exorbitant, is necessary for security. See North Korea vs Iran/Venezuela. Nuclear scientists, supply chains, and a trained workforce takes decades to develop. Excess power production can be used to smelt aluminum. You can always have strategic excess supply of materials that can use flexible supply.

vrighter 1mo ago

large scale is cheaper more economical anywhere else. I don't believe making reactors smaller would work differently than anything else.