Antares achieves criticality of Mark-0 reactor
antaresindustries.com
antaresindustries.com
And closely followed by Valar Atomics two weeks later: https://www.energy.gov/articles/department-energy-celebrates...
Great to see engineering deliver on time. I wonder if Rolls Royce will also have a smooth ride. It's a PWR.
I'm unsure where the H in HEU comes from, probably nasty sources, and probably nasty radiochemistry.
I wouldn't even be surprised if the achievements are like "Full-Self Driving", announced hastily with boasts and then slowly revealed to be full of Elon.
What do the other comments contribute? Do they solve inflation, wars, monopolization? Small-picture comments have small audience, like, how many people have access to nuclear materials and gear to make use of the information provided here? In other words "political rants" have their place and in many cases they are more valuable than the rest.
Are there any other examples of land-based militaries using nuclear power? Seems kind of like since they can't talk about the energy transition or w/e this has to be a military thing instead.
Instead of parking diesel generators up at Arctic radar stations (and other remote locations), we'd use a nuclear reactor, which is a logical choice.
The problems were:
1) one control rod could send the entire reactor prompt critical
2) rods could get stuck, requiring that they be "exercised" very carefully as to prevent them from making #1 happen
3) this maintenance was being done by a man in his early 20s who had been sleep deprived and received a phone call before his shift from his wife asking for a divorce
The result was the only immediately-fatal reactor accident in American history.
Glad to see that we're getting over this and moving forward with the concept. Only took us 60+ years...
Should we double down on renewable energy and solve its issues with lots of batteries or should we invest in next generation nuclear energy?
Both at the same time?
Does anyone know?
https://unece.org/sites/default/files/2022-04/LCA_3_FINAL%20...
I think a low carbon mix will result in the cheapest, most reliable and cleanest energy grid.
Do it all.
Nuclear really has to go big (supply most of the world's energy) or go home. But supplying most of the world's energy means burner reactors are inadequate -- there isn't enough cheap uranium. Burner microreactors have even worse neutron economy, so this argument applies even more so to them.
Renewables and batteries to keep your AC, workplace EV charger, stove, pool heater and (since recently) green ammonia producer going, nuclear to prevent e.g. aluminium smelters from seizing up.
Also the cheapest way to make renewables work 24/7 is to build HVDC lines - they cost as much as a highway per unit length and even undersea cables would deploy for less and faster than equivalent nuclear.
The total length of HVDC lines just in China is currently more than 40k km, so they've literally deployed enough of them to wrap around the globe.
https://ourworldindata.org/grapher/co-emissions-per-capita
Not saying they’re not also building renewables and nuclear, but it seems like the policy is more “build anything and everything to satisfy demand” than a focused effort.
BTW: if you look at US emissions, the data center bubble hasn’t had much if any effect. They are still trending down. There’s reasons to dislike that industry but I’m sick of the mindless echo chamber doom on that issue. They’re not that significant in the grand scheme of things.
An additional data point to support that is that emissions intensity per GDP is clearly falling fast for China [3].
[1] https://ember-energy.org/data/electricity-data-explorer/?ent...
[2] https://ember-energy.org/data/electricity-data-explorer/?ent...
[3] Chart 75 from here: https://robbieandrew.github.io/GCB2025/
Personally I doubt that, as US emissions have been going up due to data centers:
https://www.reuters.com/business/energy/us-leads-global-co2-...
And while China, like you said, doesn't seem to have a focused goal, it so happens that renewables are the path of least resistance for just having more energy as fast and cheap as possible.
They also passed everyone as top emitter of produced goods, which almost everyone else has outsourced to there. So what?
Buy less? Buy American? European? More expensive? Reshore?
If you don't: stick to renewables.
And it also depends on what you mean by "we". As a Dane, I don't think us Danish taxpayers should invest in nuclear energy, but I'm perfectly happy that private Danish investors invest in Seaborg/Saltfoss and Copenhagen Atomics.
The empirical evidence has nuclear being uncompetitively expensive. The current focus on variant reactor designs appears to be something of a Hail Mary attempt to get around this sad state of affairs.
You sometimes see them making an argument about energy density, which goes back to Vaclav Smil. But Smil used this argument to massively mispredict how solar would be go in the market. We don't hear him much anymore.
Nuclear advocates increasingly resort to conspiracy theoretic reasoning to explain away the failure of their technology to compete. This should be a red flag.
France nuclearized 75% of its grid in the 1980s while the solar folks were faffing around. It's not a cost issue, it's that anti-nuclear folks have choked out the industry.
We need to take the boot off the neck of nuclear. Wind and solar aren't an avenue to moving up the tech tree of civilization, which will involve using vastly more power.
What we do know is their attempt to build more NPPs now has gone spectacularly tits up, with costs completely out of control. This should make one view their earlier efforts with great suspicion. Have they become much worse, or were earlier problems concealed?
Or, maybe, it really is complicated and needs regulation to keep it sufficiently safe in a world where corners are always cut.
Life isn't Civ 6, there is no tech tree to climb.
Extending an abstraction beyond its expressive capabilities is an error IMO.
I have a solution, take the subsidies spent on "renewables" and put them into nuclear! Easy peasy!
If nuclear had shown good experience effects it too would have merited its subsidies. Unfortunately it hasn't done that.
We should be investing in all non carbon emitting sources and we should have been doing it since the 1970s when we figured out pretty conclusively that this would be a problem.
Instead we had right wing fossil fuel shills on one shoulder and unscientific woo woo greens on the other, the net effect being that we kept burning more carbon. We still have them, Trump with “beautiful coal” and greens now opposing even solar power and batteries, but climate change is no longer possible to ignore. Some still manage it but those people are nuts.
If we hadn’t stopped improving nuclear we’d probably have emitted half the CO2 we have. It would have become cheaper and safer and more scalable and then when China industrialized they would have copied that instead of burning so much coal.
France with its nearly zero carbon grid is the existence proof.
It wasn’t until the 2010s that solar and wind became grid scale in a big enough way to matter. That was too slow.
Whether someone is at least open to nuclear power is my litmus test for whether they take climate change seriously.
I do. If we hit 600, 800, 1000 ppm CO2, which is possible if the world keeps developing on the back of fossil fuels, we are entering existential risk territory. Earth has had those CO2 levels before, and higher, but our species was not alive then.
We already passed the FAFO threshold for ppm CO2 and now we will FO. But that’s not X-risk yet. I’m talking about the next threshold, which may start around 600 but really kicks in near 1000. This is where you actually start asphyxiating. You get lowered IQ and impaired judgement to a small degree, but across the globe at a time when we really don’t need it.
https://antaresindustries.com/
It also uses a Brayton cycle generator with nitrogen instead of steam.
(See 03, 04, 06 in their schematic outline.)
The French reprocess and recycle fissile material but that’s kind of a gnarly industrial process. Still they do it and it works.
The long term solution is to create a second kind of reactor that has a higher burn fraction which means a more fuel efficient fast reactor. Those would be, ideally, the big base load plants if we did this rationally.
And who wants spent nuclear fuel in low earth orbit? This is a far worse location for spent fuel than buried in a bunker. This is a worse location than Times Square.
Low earth orbit would just be where it's transferred to something to carry it farther out, for example using solar-electric engines.
For all this, remember it isn't done immediately, it's done in (say) 300 years when the short lived fission products are mostly gone.
Plus even if this were free, “shoot 180k tons of nuclear waste into space” seems like a terrible idea in general. It’s one of those ideas that make sense only until you think about the ramifications. What happens when inevitably one of the 3 thousand Falcon heavy rockets explodes and the armor fails and we spread nuclear waste over 3 states?
A full launch on F9 (with recovered S1) is estimated to cost $15M and can put up to 17,600 kg into LEO, or $850/kg.
> (>4 accounting for the 10x launch armor).
You're double counting there. 3x would be just fine even with 10x launch armor.
> seems like a terrible idea in general
And here's the problem: you started from an emotional reaction and are trying to rationalize that.
Estimated by who? SpaceX charges 74 million for this. Nothing credible I can find indicates that SpaceX is running an amazing 80% profit margin on Falcon 9 launches.
> And here's the problem: you started from an emotional reaction and are trying to rationalize that.
No, your premise is “just launch the trash into space” and you’re hand waving away the complexity, costs, and danger.
Anyway, the number is from fairly old Musk interviews. Costs have likely decreased since then.
https://www.nextbigfuture.com/2026/02/spacex-falcon-9-true-c...
> No, your premise is “just launch the trash into space” and you’re hand waving away the complexity, costs, and danger.
At least I didn't trot out a string of obvious errors like you did.
When people do that, it's a strong tell they're engaging in broken thinking. What you did, I think, is believe something, then try to rationalize it. When your thinking reached a justification you liked you just stopped thinking (because, after all, thinking more could break the pleasing argument you just constructed, and that would feel bad).
Is your premise that SpaceX will ship nuclear waste at or below cost? Because the 74 million is a publicly available price. And when SpaceX ships stuff for the government the prices go up, not down.
> Anyway, the number is from fairly old Musk interviews.
Yes, Musk is famously honest and accurate with his claims.
> At least I didn't trot out a string of obvious errors like you did.
What obvious errors are those? You don’t seem to like that I’m using publicly available pricing.
> When people do that, it's a strong tell they're engaging in broken thinking. What you did, I think, is believe something, then try to rationalize it. When your thinking reached a justification you liked you just stopped thinking
Pot, meet kettle. You are basing your entire premise on a speculative future that doesn’t exist. You should have just proposed sending it up the space elevator.
None of this idea makes sense from a financial, physical, or risk stand point. “This stuff is too dangerous to store in a hole, let’s launch it into space in 3000 rockets, and then we’ll push it away from earth with another thousand solar electric rockets, and then we’ll use solar energy to evaporate it all! What could go wrong?”
Honestly if you’re betting on a hypothetical future where all this is effectively free, why not just bet on a future where reprocessing uranium drops in price as well?
Orion (in its fission bomb form) is impractical and would be insane to launch from Earth, but it holds the title of being the only “torch ship” drive we know how to build. We could technically build it.
I can purchase produce grown on a different continent for less than that at the grocery store so something isn't right here.
Freight cost is certainly way lower.
The elements that are used in nuclear reactors (particularly Uranium and Plutonium) are pretty dense, and thus heavy.
> 50+ pounds of fuel
Just out of curiosity, how much do you think LOX/LNG propellant costs?
Metaphor. Allegory. Analogy. Parable.
The only downside is the “waste” is quite valuable. MSRs can also use it, and their waste is only dangerous for ~300 years.
The waste, likely packaged in torpedo shaped structures made of corrosion proof, high density, high strength materials, would arrive at somewhere around 150 MPH. Being extremely dense and heavy, they would penetrate deeply into the sea bottom, estimated at 35-55 meters deep. There’s no chance they’d somehow be forced back to the surface. Even if they were, being sealed they would be harmless.
Even if by some miracle one broke open at the sea floor, the nuclear material is dense and wouldn’t disperse. There’s very little life to affect down there regardless.
For a thorough analysis (which shows how useful the frontier models are getting at this kind of thing), see https://x.com/i/grok/share/276607c72b5e4f639527935cbc614fa0
The "eh, just bury it" approach is really not a bad one. Its not even that much stuff to bury
[1] https://worldnuclearwastereport.org/
[2] https://www.eia.gov/todayinenergy/detail.php?id=16651
[3] https://www.colorado.edu/ecenter/2021/04/15/hidden-damage-la...
What concerns me is that 250 years of fossil fuel energy continues to store its waste products in my lungs and the water I drink. That's the issue we need to solve with urgency.
Other than marketing propaganda, there isn't much real information about Mark-0. I'm assuming it's a sodium cooled, slow and hot pebble bed reactor. Hot pebble beds are well known but one with sodium cooling appears to be a first.
Why slow sodium? You get all the risks associated with sodium with none of the benefits of fast neutrons. There are operational, electricity producing, fast sodium reactors which do make some sense. I can't say the same for Mark-0.
> "The demonstration and the licensing pathway it establishes represent a key step toward deploying electricity-producing microreactors for U.S. military installations by September 30, 2028."
So which is it? Power to the people or power to the military? This microreactor concept doesn't seem very well suited for commercial use.
Rooftop solar is an example of small scale decentralized energy production, maximum efficiency is not the only relevant metric.
> And you probably don't want dozens of "microreactors" scattered across cities
Why not? If they're considered safe and pass all inspections, what's the problem?
Rooftop solar does not have these issues.
Secondly although generating large amounts of power is more efficient in terms of generation, generating power close to the point of use is significantly more efficient in terms of power loss on the grid as I understand it.
They have diseconomies of scale. Some of the costs of a nuclear power plant scale sublinearly with power. Neutron economy is improved in a larger core. Larger turbines are more efficient than smaller turbines. It doesn't take 1000x as many operators to operate a NPP with 1000x the power output.
You'd also probably find similar issues with diesel generators, but small diesel generators do roaring trade and have great commercial applications.
Diesel generators have the advantage of being very cheap -- an order of magnitude cheaper than NPPs per unit power output -- and of having much of their total cost being fuel cost, so they can operate at lower capacity factor. But even so, we don't see large power plants composed of arrays of diesel microgenerators.
(The solution for current higher capacity factor diesel users, like say remote operation at mines, would be to supplement them with renewables and storage to reduce fuel costs. This is already happening.)
A significant problem with any small power plant is fixed costs. A 1 MW(e) plant (Antares is said to be between 100 kW(e) and 1 MW(e)) making power at 90% capacity factor and selling at $0.05/kWh will gross about $400K/year. A single full time employee, like a security guard, will cost a good chunk of that.
Oh sorry, I thought you were talking about efficiency. Ok, what is the cost is for these plants?
> A single full time employee, like a security guard, will cost a good chunk of that.
I dunno, a 1MW nuclear plant could end up being pretty small. It might easily be economic to install them places that already have security guards.
All of these reactors were built in the early 1960's and the last (MH-1A) was retired in 1978. All of them were operated in places that had lots of soldiers around (though McMurdo and Camp Century relied more on being really difficult to get to than actual sentries) And they were never replaced. Because even having guards already paid for didn't help the economics of the situation. Maybe things are different now. But I've yet to see any evidence for it.
They were all buried in shielded caskets, several feet deeper than normal.
Crippling diseconomies of scale.
That distinction matters because nuclear.
Let that sink in for a moment.
Since you've adjusted this in the past, I'm sure you can do so again, and we'd appreciate it. We like that you're here, but need you to stay within the guidelines.
I never do flamebait and rarely do snark tho (usually only after several increasingly futile exchanges).
Flippant comments (like the autotune one) and/or sincerely held even if unpopular opinions, I'll stoop to, yes.
Unpopular opinions are fine in principle - we definitely want to hear minority views on HN. But it's super common for people to pre-emptively load their unpopular-opinion comments with sarcastic or aggressive language, no doubt as a defensive against the anticipated negative reacction from the majority (https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...). That never works well. But I'm just speaking generally - I don't know if it applies to your posts.