Talk:Natural nuclear fission reactor

Merged talk
Moved from Oklo during merge

"since there is no physical reason why it should be exactly constant" is not well phrased. It is expected that the fine-structure constant is, exactly that - constant. Controversy arises from the fact that certain measurements described in the fine-structure constant article indicate it may have shifted over time. I have changed it to ", as new evidence suggests is possible". --JoeMeyerowitz 1/2/06


 * This is misleading for two reasons. First there is a long tradition of theoretical physics speculation about models where the so-called "fine structure constant", and/or other parameters, actually change very slowly with time. Theoretical models date back to Dirac in the 1930's. The original statement that there is no reason why it must be exactly constant is quite correct: these are parameters which a priori are continuously variable. Second, what has happened recently is the appearance of claimed signals of nonzero variation in astrophysical spectra, which is an experimental result. The new evidence does not "suggest that change is possible" since that was known all along; it suggests that change may actually have occurred. --Tdent 12:00, 20 September 2006 (UTC)

"A key to the creation was that at the time, the abundance of fissionable U-235 was about 3%, which is comparable to the amount used in today's reactors. Due to U-235's shorter half life than U-238, the current abundance of U-235 in natural uranium is about 0.7%. Therefore a natural nuclear reactor is no longer possible on Earth."

3% of what? I assume the 3% in the first sentence means 3% of natural uranium, as in the second sentence. This is ambiguous. --Jsnow 03:20, 22 August 2005 (UTC)

What about James Lovelock's claims that the Uranium was concentrated by bacteria? See his book The Ages of Gaia (1988).

I removed the "nuclear skullduggery" or whatever it was. If anyone knowledgeable can replace it with something comprehensible, it would be greatly appreciated.

I believe that the definition is wrong. A natural nuclear fission rector is a exactly that. Such a thing could occur at any time or place. The definiton limits it to the past. That is logically wrong. —Preceding unsigned comment added by 124.197.15.138 (talk) 21:52, 4 December 2010 (UTC)

Question
Are there any other sites than Oklo? thx.
 * So far no other sites have been found --21:26, 28 March 2006 (UTC)
 * Then why not replace 'best known location' with 'only known location?' 'best known' implies that there are other, more obscure ones. 69.249.92.211 16:25, 30 June 2006 (UTC)
 * Pending any clarification from an expert, I'll make that edit myself. 69.249.92.211 14:50, 11 July 2006 (UTC)

From:jjf I have another reference: Scientific American, July 1976 p.36 George A Cowan A Natural Fission Reactor —Preceding unsigned comment added by Foxjj (talk • contribs) 13:04, 11 October 2007 (UTC)

Timing
At one point the article states that the reactions occurred 1.5 billion years ago, while at another point it says the reactions took place over 2 billion years ago. Can someone clarify and/or correct this? How long did the reactors operate? Paul D. Anderson 06:28, 1 September 2006 (UTC)

omg
This is incredible. 67.183.178.23 02:53, 8 June 2007 (UTC)
 * Well put! I look forward to this article growing over time, as it is a darn neat topic. Dxco (talk) 22:44, 27 February 2008 (UTC)

I believe I read somewhere, years ago, that mutations due to natural fission were considered a contributory factor to evolution. Is there any truth in that ... any citations? Delverie (talk) 17:00, 27 July 2009 (UTC)
 * There is a recent article in GSA oday suggesting that isolated oxygen producing photosyntheses-driven biological communities in the mostly reducing environment of the Archean contributed to the formation of natural nuclear reactors. However, as a negative feedback, this reactors may prevented the spread of oxidising life forms. See article: Did natural reactors form as a consequence of the emergence of oxygenic photosynthesis during the Archean?Geomartin (talk) 06:28, 16 October 2009 (UTC)
 * IIRC Isaac Asimov's Foundation series speculated that there was a relationship. I think it was in Edge of Foundation or Foundation and Earth, from the 1980s.  Given he was a biochemist, and almost got assigned to the Manhattan Project during WWII, it's not too wild to suppose this idea was kicked around among colleagues and friends.  He died in 1992.

4.249.63.191 (talk) 21:45, 31 October 2011 (UTC)

I would love to see the original sources for the initial reactions once the 235U discrepancy was noticed! It would let us write such a cool article with a dramatic history section! (^_^) Double sharp (talk) 04:09, 22 June 2016 (UTC)
 * This Scientific American article is interesting – it talks about the Xe isotopic anomalies that resulted (case in point: the trapped Xe we have is not a direct fission product but the daughter of Te and I) – but we'll have to look for the original source for this. Double sharp (talk) 10:51, 5 February 2018 (UTC)

Iron
As the most stable nucleus, Iron very well may serve in critical background processes in both stellar and terrestrial nuclear formations. 74.195.28.79 (talk) 09:25, 30 September 2008 (UTC)

Impossibilty of natural reactors under current conditions
I undid the change regarding the possibility of natural reactors by ID 98.210.108.122. It is true that Magnox and CANDU reactors use natural uranium instead of enriched uranium, however the conditions in these reactors are so special that they are not compareable to nature. For instance, CANDU reactors use heavy water as moderator, which does not occur in nature in concentrated form. Therefore the statement in the article remains true that natural fission reactors are not possible anymore on earth.Geomartin (talk) 04:51, 16 November 2009 (UTC)

Mechanism of the reactors
This part sounded very suspicious: "After cooling of the mineral deposit, short-lived fission product poisons decayed" So I checked out the citation and found that it wasn't in there. In fact, this is what the paper says: "Interestingly enough, the 30 min pulses of natural nuclear reactor activity and 2:5 h dormant periods re- corded in the Oklo Al phosphate resemble a typical geyser operation. Similar time scales suggest similar processes. This similarity suggests that 0.5 h after the onset of the chain reaction, unbounded water was converted to steam, decreasing the thermal neutron flux and making the reactor subcritical. It took at least 2.5 h for the reactor to cool down until fission Xe began to retain. Then the water returned to the reactor zone, providing neutron moderation and once again establishing a self-sustaining chain." My guess? Some editor added "poisons" to describe the (biologically nasty) short-lived fission products for some reason, and another interpreted that as neutron poisons. So unless someone sources that statement, I'm removing it. Kolbasz (talk) 13:35, 29 October 2011 (UTC)
 * Done. Kolbasz (talk) 12:23, 1 November 2011 (UTC)


 * The word poison looks like it refers to neutron poisoning, not biological poisoning. However, at this point, every use of poison in the article is preceded by the word neutron, so the word is fine. —MiguelMunoz (talk) 02:27, 27 April 2024 (UTC)

would be nice
The diagram is nice; a map would be nice too. I don't read coordinates very well. 4.249.63.191 (talk) 21:36, 31 October 2011 (UTC)

Is 'reactor' correct terminology?
I admit I don't know much about school-level physics (& nothing at all about geology) beyond what any vaguely scientifically interested person might pick up in adulthood, but is it correct to describe it as a reactor anyway? Is it only a reactor if it's actually *doing* something with the reaction - such as generating electricity - rather than simply existing? Would a more accurate title be 'natural nuclear fission phenomenon' or something? Note that I'm asking to seek knowledge, rather than asking as a rhetorical device to make a point! Star-one (talk) 16:12, 13 April 2012 (UTC)
 * A nuclear reactor doesn't have to do anything, power-wise. For example, the Hanford production-reactors in the Manhattan project just sat there and generated heat (had to be cooled with water) but generated no electricity. Their job was to fission U-235 and make Pu-239 out of U-238 with the neutrons produced. The better question is whether the word "reactor" itself demands an artifact-- something made by humans. Most people writing about this have tended to take the view that if you qualify the word by writing "natural reactor" it's okay. Or rather is a permitted conceit, like writing of certain stalactites as natural chandeliers, and so on. S  B Harris 17:21, 13 April 2012 (UTC)

Comment

 * Quote: "Oklo is the only known location for this in the world". I thought Morro do Ferro? (thorium deposit), Poços de Caldas, Minas Gerais, Brasil had a natural nuclear fission reactor as well.
 * I hope it's the right reference: Natural analogues for the transuranic actinide elements: An investigation in Minas Gerais, Brazil (1984), Environmental Geology and Water Sciences, Springer, Volume 6, Issue 1, pp 1-9.
 * Proc. Technical Committee Meeting on Natural Fission Reactors (1978), IAEA Tech. Rep., STI/PUB/475, IAEA, Vienna, Austria.
 * or Gancarz, A. J. (1977). Technical Committee Meeting on Natural Fission Reactors, December 19-21, 1977 Paris, France.
 * W. Miller, R. Alexander, N. Chapman, John C McKinley, J.A.T. Smellie (2000) Geological Disposal of Radioactive Wastes and Natural Analogues, Elsevier, pp. 328
 * Chapman, N.A., McKinley, I.G. Shea, M.E. and Smellie, J.A. (1990): The Poços de Caldas Project: Summary and Implications for Radioactive Waste Management, SKB Tech. Rep., TR 84-16, SKB, Stockholm, Sweden.
 * But I can't confirm that it was a natural fission reactor. Regards --Chris.urs-o (talk) 10:19, 12 January 2013 (UTC)


 * The criticality event at Tokaimura operated the same way: http://www.world-nuclear.org/info/inf37.html by voids being created and briefly stopping the reaction until it cooled sufficiently to restart. And transmutation of elements via accelerated deuterium from cloud top accelerators means accululation is possible.  www.execonn.co,/cropcircles/isotopes.html--68.188.203.251 (talk) 14:11, 14 February 2013 (UTC)

ksisco

Mars speculation
I think the part of this article related to Mars is totally bogus and relies on non-peer reviewed speculations from a non-geologist. If you read the linked Space Daily reference, the GRS principal investigator is quoted as saying pretty much the same thing. Suggest that this whole section should be removed. — Preceding unsigned comment added by 138.110.75.55 (talk) 15:55, 27 February 2013 (UTC)


 * I agree this theory is wild and as it hasn't been published under peer-reviewed skipping the Mars part of the article seems reasonable. --Danapit (talk) 17:23, 27 February 2013 (UTC)


 * Just removed the edit about "explosive end to Martian natural reactor". I did it without announcing to the author of the contribution, because he/she was not logged in when editing the article. The reason of deleting is that (as mentioned above) it is a speculation. Not sure about removing the whole section, hope to get more contributions to this discussion. --Danapit (talk) 11:06, 8 March 2013 (UTC)

Assessment comment
Substituted at 00:57, 30 April 2016 (UTC)

Reference to the Origin of the moon hypothesis
Going through the paper of Westrenen et al. cited in that section of main page, it is clear that an Oklo-type natural reactor is not involved in their origin of the moon hypothesis. Discrepancies in timing (moon formation vs Oklo-type reactions) and location (mining depths vs core-mantle boundary) suggested that the referencing might be improper. I suggest that the section be deleted or rather, moved to the Moon page. Nrlsouza (talk) 01:36, 23 November 2016 (UTC)

Oklo: critical or non-critical?
The "Mechanism of the reactors" section states that Oklo (at least, I think it's referring to Oklo) went critical. However the article on Oklo itselfs implies that it did not go critical, only that it could have done if conditions had been different. So which is right? — Preceding unsigned comment added by 195.226.136.112 (talk) 12:59, 21 December 2016 (UTC)
 * Yes, Oklo was critical when operating as a natural reactor. I do not see anything in Oklo that implies otherwise. VQuakr (talk) 01:11, 3 March 2017 (UTC)

wrong lemma
Far as i know Nuclear chain reactions can occure on planets but nuclear fission is an entirely different physical process that can only happen in a sun, at pressures and temperatures which are impossible for planets. I read about "natural" chain reaction geological scenarios and some of thouse may even have been on our planet so the article seems ok but the lemma is wrong as its not about nuclear fission but nuclear chain reaction. --Kharon (talk) 00:22, 3 March 2017 (UTC)
 * You are confusing nuclear fusion and nuclear fission, both of which can be involved in nuclear chain reactions. VQuakr (talk) 00:54, 3 March 2017 (UTC)
 * Damn :p. Thanks for correction! --Kharon (talk) 11:32, 4 March 2017 (UTC)

U-234 to mention or not to mention?
The Uranium then as now had a trace component of due to alpha decay of. I wished to add this fact in a relevant section. User:VQuakr is/was opposed and reverted me. So. How do we proceed? Hobbitschuster (talk) 01:23, 2 January 2022 (UTC)
 * The ubiquitous presence of trace 234-U isn't relevant to the paragraph, which is about how ancient natural uranium had a higher concentration of 235-U than today. VQuakr (talk) 01:26, 2 January 2022 (UTC)
 * We could argue with the same reasoning that U-238 isn't relevant when discussing the U-235 content. I think we should either only mention the isotope we particularly care about or all that are present. Hobbitschuster (talk) 14:50, 2 January 2022 (UTC)
 * Effectively there are two isotopes present, 235 and 238. The presence of 234 (along with 233 and 236, technically) is trivia. VQuakr (talk) 23:24, 2 January 2022 (UTC)

It probably depends on how much thorium is in the rocks around there and the neutron flux while the reactor was going. Thorium-232 can absorb a neutron to become Th-233 which in turn can absorb another neutron to become Protactinium-234 which decays into U-234. See the thorium cycle. Given the half life of those species, I wouldn't bet on it happening recently. There are about 6800 half lives of U-234 since the reactor was active. (2^6800 is an absurdly big number, so pretty unlikely any remaining U234 is from that) I'm really just pointing out there is possibly more than one place U233 and U234 might have come from historically.
 * where would the others be coming from? Hobbitschuster (talk) 00:00, 3 January 2022 (UTC)
 * Cosmic ray strikes I believe, but don't quote me on that. VQuakr (talk) 17:09, 6 January 2022 (UTC)

So, a discussion with two participants hasn't reached any conclusion. What are now my options if I am still in favor of the edit I made, but I wish to avoid an edit war? Hobbitschuster (talk) 16:02, 6 January 2022 (UTC)
 * Honestly this is silly, there's not way it's editorially favorable to include this proposed content. But for lightweight dispute resolution I suggest WP:3O. VQuakr (talk) 17:09, 6 January 2022 (UTC)
 * Hi, I'm not an expert on these topics and I don't want to cause any trouble here. My opinion is that I'd prefer to have a bit more information on the page (as long as it is reliably sourced), even if it might be considered trivial by many, than having less information. If it is related to the topic, that's why I come to Wikipedia: to learn more about it and its nuances. ACLNM (talk) 16:03, 9 January 2022 (UTC)
 * The issue is that it isn't related to the subject. If someone wanted to know more about the subject under discussion in this thread they could read isotopes of uranium. VQuakr (talk) 20:00, 9 January 2022 (UTC)
 * I'd prefer to have the deleted half-sentence back. I had never been to isotopes of uranium before, but I've visited natural nuclear fission reactor as a geology topic a few times. The mention of taught me that the distribution wasn't just purely the binary  (31000 ppm) and  (969000 ppm), but slightly less (than these concentrations), so to accommodate the traces (~55 ppm; from the isotopes article) of the third isotope . Instead of suggesting the removal the half-sentence, I question: what else could we had to the article to make it even more interesting and complete? ACLNM (talk) 22:25, 10 January 2022 (UTC)
 * Information for the sake of information isn't a good standard, as discussed here. We are editors. We take out what isn't relevant to a given subject. I did add a link to isotopes of uranium at a logical place in this edit, though, which I think is a step in the right direction. VQuakr (talk) 03:40, 11 January 2022 (UTC)
 * is one of many transitory radioactive isotopes that are produced by the decay of and . As transitory isotopes go, it does have an unusually long half-life, but it's still transitory. Only the  and  isotopes are left over from the creation of the Earth, which is why we mention them. The scientists who first analyzed this site looked at a lot of the trace (and mostly stable) decay products in their investigations, and they all had tales to tell, but don't really deserve mention in this article. I don't see why  deserves any special mention outside of a professional journal. But you're welcome to make the case here. I would like to see the edit in this section. —MiguelMunoz (talk) 01:19, 27 April 2024 (UTC)

Life on Earth in that Era
When I tell people about this discovery, they always ask how it affected the local plants and animals. They imagine animals getting too close and dying of radiation sickness. So I added a sentence clarifying that there were no land animals or plants at the time. MiguelMunoz (talk) 01:00, 27 April 2024 (UTC)