6 ms·
Oklo, the Earth's Two-billion-year-old only Known Natural Nuclear Reactor (2018)
- wjnc 1y agoThis article could be so much better: How large are the estimated stores of ore that underwent natural fission? How much energy did it release and over how much time? When? Would this be noticable (and to whom)? So many questions, so little information. I only know (or knew) high school physics, and when entering this in Claude I get an answer but am unable to verify the answer. Claude says 680 kWh gained per 0.03 grams of U-235 lost due to fission. I am left wondering into what the U-235 fizzed into (sorry, pun) and if I should take that into account. Edit: There we go with modernity. I went to Claude instead of Wikipedia. Wikipedia at least has the answers. Thanks u/b800h. 100kW of heat on average. I can start filling in the blanks now.
- danielbln 1y agoWikipedia is the best first point of entry, but if you do use Claude, just tell it to do web search for you: https://claude.ai/share/73e67582-3e03-454b-aa12-e8906bd7b3fd https://claude.ai/share/73e67582-3e03-454b-aa12-e8906bd7b3fd
- croes 1y agoWhy not just do a web search?
- geocrasher 1y agoI can't speak for users of Claude, but as a user of Perplexity, having an LLM do a web search has uncovered sources I'd never have considered. The only time I use Google anymore is when I know exactly what I'm looking for. When I'm in research/discovery mode, I use Perplexity. Its search/analysis is a lot slower than a Google search, but saves me time overall and generally gives me solutions that I'd have to spend time sorting through a Google search to find, in less time than it takes to do so.
- wjnc 1y agoClaude gave a great answer at the link, at least for me. There might be a plus in learning as well since the answer is well structured with a recognizable style. Say, the scientific article above, has a distinct style and really was not high school physics level.
- the_arun 1y agoI wonder why Claude’s answers aren’t equal or better than Wikipedia - assuming Wikipedia is one of the training datasets. Is the temperature causing it to be probabilistic & other sources are carrying more weight?
- lazide 1y agoYou can think of a LLM as a type of lossy compression of knowledge. With that in mind, is it really surprising that you don’t get the ‘right’ answer out? Any more than if you compress an image with JPEG, a given pixel isn’t the ‘right’ color anymore either? They’re both close (kinda) at least, which is the point. If you wanted the exact right answer, don’t use lossy compression - it’ll be expensive in other ways though.
- ksenzee 1y agoWhat a great metaphor. I’m adopting that immediately, thank you.
- pfdietz 1y agoUranium was very enriched back at the formation of the Earth, so for a given geometry it would have been much more reactive. However, uranium ores are often formed due to redox processes, since U(VI) is much more soluble than U(IV). So maybe concentrations wouldn't have been as common back before the Great Oxygenation Event about 2.4 Gya. Still, that leaves ~600 Mya between that point and this reactor, which would be not quite one half life of U235.
- adev_ 1y agoThe 'natural reactor' in Oklo has been discovered by some french researcher from the CEA in the 70s. There is an entire scientific publication on the topic if it interests you: https://www.sciencedirect.com/science/article/abs/pii/S0016703796002451?via%3Dihub https://www.sciencedirect.com/science/article/abs/pii/S00167...
- b800h 1y agoThe Oklo region has now-exhausted Uranium deposits. From Wikipedia: "Some of the mined uranium was found to have a lower concentration of uranium-235 than expected, as if it had already been in a nuclear reactor. When geologists investigated they also found products typical of a reactor. They concluded that the deposit had been in a reactor: a natural nuclear fission reactor, around 1.8 to 1.7 billion years BP – in the Paleoproterozoic Era during Precambrian times, during the Statherian period – and continued for a few hundred thousand years, probably averaging less than 100 kW of thermal power during that time. At that time the natural uranium had a concentration of about 3% 235U and could have reached criticality with natural water as neutron moderator allowed by the special geometry of the deposit."
- jvanderbot 1y ago100 kW for a few hundred thousand years is basically the best sales pitch for nuclear power I've ever heard. Even of "just" heat output.
- Alupis 1y agoIts impressive the amount of clean, cheap energy that's been locked away because of fearmongering tales from well before many were even alive.
- cdaringe 1y agoIt is natural and reasonable to be of two minds on the matter. Surely that’s not controversial.
- jvanderbot 1y agoAll power generation has tradeoffs. I like nuclear because it can be small, tucked away, generate _lots_ of power, and has few day to day environmental risks. Spent fuel is an issue, but there's very likely a virtuous cycle that will evolve if we start ramping up nukes again. Dry cask storage is no big deal IMHO, and something will likely evolve that either can use spent fuel or can deal with it better.
- HelloUsername 1y ago(2018) https://news.ycombinator.com/item?id=17736262 https://news.ycombinator.com/item?id=17736262
- saltserv 1y ago[dead]
- Aardwolf 1y ago> All natural uranium today contains 0.720% of U-235. That's related to the material of our solar system all coming from the same supernova explosion or similar, right? Does this apply to our entire milky way or just the solar system? What if parts collided with material of _other_ origins and some of that is on Earth, then there could be different mixes, right?
- BurningFrog 1y agoGrok says: At Earth's formation ~4.5 billion years ago, natural uranium contained approximately 23.2% U-235 These numbers are probably only for the local corner of the galaxy. It depends on when the supernova(s) that created the uranium exploded.
- _Algernon_ 1y agoWe all have access to Grok and other AI models, and we will ask it if we want it's bullshit hallucinations. There is no point polluting HN with this trash.
- deleted 1y ago[deleted]
- BurningFrog 1y agoAnyone can look it up, yet I was the only one who did.
- _Algernon_ 1y agoYou didn't look anything up. You prompted a stochastic parrot.
- CamperBob2 1y agoIs it wrong?
- 1y ago
- kkwteh 1y agoMaybe it’s a remnant from a nuclear ancient civilization.
- julienchastang 1y agoA civilization (even perhaps extraterrestrial) that possessed nuclear energy? Unlikely, but still fun to think about! ;-)
- geocrasher 1y agoMaybe it's a sign of a future time travelling civilization with nuclear power but poor navigation, warped straight into the mantle Earth's crust :D
- Gregaros 1y agoI thought where you were going with his was "that realized the best way to dispose of their nuclear waste was to dump it in the deep past." I’d read that novel.
- geocrasher 1y agoOnly to mine it later and re-use it over and over again. The 5 billion year long recycling program.
- eabeezxjc 1y agoOr a remnant of a nuclear war in a riotous time
- airstrike 1y agohttps://en.wikipedia.org/wiki/Silurian_hypothesis https://en.wikipedia.org/wiki/Silurian_hypothesis
- deleted 1y ago[deleted]
- legitster 1y agoRichard Rhodes brought this up in an interview. He made it a point for critics who say nuclear waste can't be safely disposed of through burial. Well, we have pretty good natural evidence that nuclear fission products can remain buried and undisturbed for a pretty long time!
- mystified5016 1y agoIt was undisturbed until humans came around and specifically went looking for uranium and dug up the spent reactor fuel. Which is kind of a problem for future burials because humans exist now and want and know how to find uranium. The time between humans cracking the atom and the excavation of this nuclear waste is only a few decades. It took less than a hundred years for humans to find this nuclear waste in the ground. Your argument is not well-founded. Burying nuclear waste for it to be discovered and excavated in less than a century is not nearly long enough.
- krunck 1y agoThis is nonsense. Yep, after 2 billion years this thing is now safe to touch. But that had nothing to do with it's burial. We at least have pretty good evidence that nuclear fission products can be exposed to groundwater/hydrothermal fluids for a pretty long time.
- sliken 1y agoNot sure I'd call it safe to touch. Getting with 5cm for an hour gives you as much radiation as a 8 hour flight. I wouldn't want touch it, make jewelry from it, or any substantial near promity. Not to mention if it was "only" a billion years ago it would be MUCH MUCH worse.
- joe_the_user 1y agoI don't disagree that nuclear waste can be disposed of safely under good conditions[1]. But I think a fallacy to claim that natural phenomena should inherently be considered "environmentally safe" in human terms. There are coal seam fires that have been going on for centuries and the pollution of these is just as bad as the pollution generated by human created coal mine fires (and that's truly awful, a significant source of carbon pollution). [1] The problem with nuclear reactors isn't that their pollution couldn't disposed of with ideal methods but that when they run by for-profit corporations, you will always have the company skirting the edge of what's safe 'cause corporations just go bankrupt with catastrophic events and so their risk-reward behavior isn't the risk-reward optima for humanity.
- foobarian 1y ago> All natural uranium today contains 0.720% of U-235. If you were to extract it from the Earth’s crust, or from rocks from the moon or in meteorites, that’s what you would find. But that bit of rock from Oklo contained only 0.717%. Heh. The garbage web software developer me would have just called it good enough Would be really interesting to know what the error bars on those figures look like
- Analemma_ 1y agoI think it would've been good enough for the miners too, if not for the fact that nuclear arms control treaties require every gram of U-235 to be accounted for. When they were digging it out of the ground and found it was less enriched than it should've been, this needed to be explained. It has always fascinated me to think that this natural phenomenon could and probably would have remained unknown forever if not for these treaties and agreements.
- mannykannot 1y agoYou have me wondering about that as well. If the uranium was going to be enriched for use in a light-water reactor (I would guess it was), maybe the difference translates into needing more stages of enrichment to reach the required level?
- teuobk 1y agoPer NIST[1], the value is 0.7204% +/- 0.0006%, with the uncertainty representing one standard deviation. [1] https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=U https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl...
- curtisszmania 1y ago[dead]
- fnord77 1y ago> only known natural nuclear reactor um, stars?
- preisschild 1y agothe word "fission" is missing https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...
- eapriv 1y agoum, “Earth’s”?
- stmw 1y agoFun aside - Oklo is also the name of a successful YC company that makes a passively-safe nuclear reactor - https://www.oklo.com https://www.oklo.com
- keepamovin 1y agoThen they picked a very clever name.
- acidburnNSA 1y agoThey are certainly financially successful. But they haven't split an atom yet so jury is still out on whether their reactor products work well.