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Is 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
by api 3mo ago
Is 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, the big base load plants if we did this rationally.
- pfdietz 3mo agoIMO, the long term solution will be to simply launch the waste into space. With low enough launch costs the extra mass needed to armor the waste against accidents becomes tolerable.
- jampekka 3mo agoCan't wait for one of those launch rockets to explode in the atmosphere!
- api 3mo agoEconomically absurd, much more expensive than reprocessing or fast waste burning reactors.
- pfdietz 3mo agoI 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 cheaper than reprocessing.
- dpark 3mo agoWhy 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.
- pfdietz 3mo agoWhy wouldn't they be low? In the limit, if launch becomes operationally similar to air travel, costs will be a few times propellant cost. And propellant is very cheap. LOX is almost free (the second cheapest industrial liquid after water) and liquid methane isn't very expensive either. 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.
- dpark 3mo agoI 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 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?
- hgoel 3mo agoProbably not worthwhile. If you just leave it in orbit you're going to have to track it and worry about debris/micrometeoroid strikes. The ideal would be to stick it in some permanently shadowed crater on the Moon, it'd be a stable environment without wild temperature swings and much lower risk of somehow ending up where people are. But that's a long way to go and a lot more risk to take for now.
- dpark 3mo agoUnless you live in Sci Fi future where space travel is magically free, this is a pretty bad deal since sending a pound of spent nuclear fuel out of earth orbit takes 50+ pounds of fuel. Sending all the spent nuclear waste into space would be something like 10 million tons of fuel.
- pfdietz 3mo agoIt doesn't have to be free, it just has to have a low cost. And remember, we're talking not about the cost now, but the cost up to centuries in the future. The ultimate time limit is set by when spent fuel stops being self-protecting against amateur diversion of the plutonium, which is 300-500 years. > 50+ pounds of fuel Just out of curiosity, how much do you think LOX/LNG propellant costs?
- LargoLasskhyfv 3mo agoHaven't you seen https://en.wikipedia.org/wiki/Space:_1999 https://en.wikipedia.org/wiki/Space:_1999 ?
- pfdietz 3mo agoYes, it's a horrible pile of pseudoscientific TV crap. Why did you imagine it was relevant?
- LargoLasskhyfv 3mo agoIt isn't even pseudoscientific, just fiction, though their 'Eagles' don't need much suspension of disbelief ;-> Metaphor. Allegory. Analogy. Parable.
- pfdietz 3mo agoIt was intelligence-insulting crap.
- LargoLasskhyfv 3mo agoIt was https://en.wikipedia.org/wiki/Rudi_Gernreich https://en.wikipedia.org/wiki/Rudi_Gernreich !
- Recurecur 3mo agoA much better, safer, and cheaper idea is dropping suitably packaged waste on the subducting side of the Mid Pacific Subduction Zone. It’d be inert long before seeing daylight again… The only downside is the “waste” is quite valuable. MSRs can also use it, and their waste is only dangerous for ~300 years.
- pfdietz 3mo agoThat's a bad idea. Subduction zones move very slowly, and material would come back up in "mud volcanoes", especially with the added heat input of the waste.
- Recurecur 3mo agoNonsense. The sea floor in those areas is soft muck, 20,000 ft or more deep. 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 https://x.com/i/grok/share/276607c72b5e4f639527935cbc614fa0
- pfdietz 2mo agoIf you're going to put it 20,000 feet deep in the sea floor, do it somewhere far away from subduction zones.
- quirkot 3mo agoEurope 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 is really not a bad one. Its not even that much stuff to bury [1] https://worldnuclearwastereport.org/ https://worldnuclearwastereport.org/ [2] https://www.eia.gov/todayinenergy/detail.php?id=16651 https://www.eia.gov/todayinenergy/detail.php?id=16651 [3] https://www.colorado.edu/ecenter/2021/04/15/hidden-damage-landfills https://www.colorado.edu/ecenter/2021/04/15/hidden-damage-la...
- fc417fc802 3mo agoI 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?
- quirkot 3mo agoFootnote has the backup. 2-3x is guesstimate, but it doesn't really matter. The answer is there's just not much waste to store
- fc417fc802 3mo agoSure there isn't a prohibitive quantity either way but regardless I think the 120k number might be off by one or two orders of magnitude even before reprocessing reduces the amount by ~95%.
- quirkot 3mo agoyou'll have to take that up with the folks from worldnuclearwastereport.org
- yabones 3mo agoI don't see the issue with dry cask storage medium term, and deep geological storage long term. Spent fuel isn't really that dangerous once it's been cooled down and for a couple decades before putting it in the ground, to the point that there are far more dangerous natural things you can dig up. 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.
- bigbadfeline 3mo agoFast 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.