Other than "not light-water", what type of reactor is it?
Antares achieves criticality of Mark-0 reactor
81–90 of 122 posts
Re: Antares achieves criticality of Mark-0 reactor
#82Is anyone working in the US on a waste solution that isn’t a big hole with a straight out of cyberpunk sci-fi warning plaque? 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,…
Fast neutron reactors can also "burn" waste from other reactors, the "ashes" are radioactive for only 300 years, there is no need for special storage after that. Untreated waste has to be kept in storage for around 100K years before it reaches safe levels of radioactivity.
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.
Re: Antares achieves criticality of Mark-0 reactor
#83Earlier quoted context omitted.
I think the onus is on you to explain why costs would drop by >3 orders of magnitude (>4 accounting for the 10x launch armor). It’s something like $1500/lb on a fully loaded Falcon Heavy and all indications are that SpaceX isn’t making money at that price. 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 unti…
Falcon Heavy is more expensive per kg than F9, because it throws away more things. SpaceX flies it for certain military missions but you will note they launch their own stuff on F9. 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…
> A full launch on F9 (with recovered S1) is estimated to cost $15M
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.
Re: Antares achieves criticality of Mark-0 reactor
#84Other than "not light-water", what type of reactor is it?
Graphite-moderated core, passively cooled with sodium filled heat pipes:
https://antaresindustries.com/
It also uses a Brayton cycle generator with nitrogen instead of steam.
(See 03, 04, 06 in their schematic outline.)
Re: Antares achieves criticality of Mark-0 reactor
#85Earlier quoted context omitted.
I’m not saying it’s literally a tree. My point is that we need vastly more power to upgrade to the next level of civilization.
Right but “upgrading to the next level” is exactly the type of cognitive error that I’m against, it’s forward-looking Whig history. There is no “levels” of civilization, there’s only the arrangements we have now and the ones that will occur in the future. Maybe those arrangements will have different pros and cons than we have now, maybe they’ll have more sophisticated engineering practices, but there’s no objective “…
It's an abstraction, not an error. Naturally you might or might not agree with any individual's underlying metrics, and them with yours.
Re: Antares achieves criticality of Mark-0 reactor
#86Earlier quoted context omitted.
Right but “upgrading to the next level” is exactly the type of cognitive error that I’m against, it’s forward-looking Whig history. There is no “levels” of civilization, there’s only the arrangements we have now and the ones that will occur in the future. Maybe those arrangements will have different pros and cons than we have now, maybe they’ll have more sophisticated engineering practices, but there’s no objective “…
It's an abstraction, not an error. Naturally you might or might not agree with any individual's underlying metrics, and them with yours.
> It's an abstraction, not an error.
Extending an abstraction beyond its expressive capabilities is an error IMO.
Re: Antares achieves criticality of Mark-0 reactor
#87Is anyone working in the US on a waste solution that isn’t a big hole with a straight out of cyberpunk sci-fi warning plaque? 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,…
Europe has about 60,000 tons of nuclear waste storage[1], so lets say the global nuclear waste quantity is 2-3x or 120,000 to 180,000 tons. That sounds like a lot, however it's less than 2 weeks of coal deliveries to a coal plant (at 1 train of 115 cars each with 116 tons of coal = 13,340 tons delivered per day[2]). To take another approach, the average landfill size is 600 acres[3]. The "eh, just bury it" approach i…
I thought something like 30 tons per Gwatt capacity per year was the ballpark for high level waste without reprocessing? How are you arriving at a 120,000 ton estimate?
Re: Antares achieves criticality of Mark-0 reactor
#88Earlier quoted context omitted.
I don't think that's the case, if launch costs are low enough. The options you describe there are quite expensive. Reprocessing costs somewhere in the neighborhood of $1000/kg. Even fast reactor have trouble disposing of the seven very long lived fission products. A fully reusable launcher might get costs down to $10/kg to LEO. Even if one had to wrap the waste in 10x its mass in launch armor this could be much cheap…
Why would launch costs be low? $10/kg is fantasy land. UPS won’t ship a kilogram across the country for $10. 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.
> UPS won’t ship a kilogram across the country for $10.
I can purchase produce grown on a different continent for less than that at the grocery store so something isn't right here.
Re: Antares achieves criticality of Mark-0 reactor
#89Earlier quoted context omitted.
Falcon Heavy is more expensive per kg than F9, because it throws away more things. SpaceX flies it for certain military missions but you will note they launch their own stuff on F9. 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…
> A full launch on F9 (with recovered S1) is estimated to cost $15M 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 th…
SpaceX charges what the market will bear, and because they have no good competitor their profit margins can be very large.
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).
Re: Antares achieves criticality of Mark-0 reactor
#90Earlier quoted context omitted.
Why would launch costs be low? $10/kg is fantasy land. UPS won’t ship a kilogram across the country for $10. 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.
> UPS won’t ship a kilogram across the country for $10. I can purchase produce grown on a different continent for less than that at the grocery store so something isn't right here.
It was a metaphor for how absurd the statement was. But if you try to ship a 1kg package across the country it will likely cost way more than $10.
Freight cost is certainly way lower.