Talk:Chicago Pile-1

The first reactor?
How can CP-1 be the first reactor (first critical in later 1942), when the Leipzig Pile L-IV already had an criticality accident on June 23 1942? --46.5.104.58 (talk) 06:40, 30 September 2013 (UTC)
 * It wasn't a criticality accident. Per List of military nuclear accidents: "During the inspection, air leaked in, igniting the uranium powder inside. The burning uranium boiled the water jacket, generating enough steam pressure to blow the reactor apart. Burning uranium powder scattered throughout the lab causing a larger fire at the facility." Hawkeye7 (talk) 00:52, 3 December 2015 (UTC)

2 Type of control systems & the curious lunch call
According to this article that appeared in the new Scientist magazine, there were two primary control systems for the control rods, one electrically controlled with a knob/variable resistor from the balcony and the other titled "zip" (probably so named due to the sound wire makes when running over a pulley at an accelerating rate) under the watchful eye of the SCRAM man/axe man to cut the line/wire.

While for finer control of the neutron rate than the electrically operated dial or knob system may have provided, George Weil operated the last "rod" or more accurately a plank. Incrementally inching it out with Fermi overlooking his progress. So there were 3 human operated control "rods" in total.

Secondly, the call for lunch at 11:30 was not random as the article in its present state suggests, but occurred right after the automated control system dropped a control rod into the fail-safe postion, doing so because it was set on too fine a hair trigger/too sensitive to neutron rates. So you see, they were slowly ramping up the reactor to a self-sustaining point and then all of a sudden this safety system wipes out all their work! So it was time to take a break and start all over again! As it was, it appears they were 2nd time lucky. Who needs to wait for third anyway?

See the bottom of page 1 and the top of page 2.

http://www.waltpatterson.org/georgeweil.pdf New Scientist 30 November 1972

Moreover the paper "The first reactor" published on the 40th anniversary in 1982 also has similar info. Along with the galvanometer chart of neutron intensity, or in the authors poetic terms, the reactors "birth certificate".

185.51.75.43 (talk) 12:06, 24 March 2016 (UTC)


 * ✅ Added to the article. Hawkeye7 (talk) 01:06, 25 March 2016 (UTC)

Accuracy?
The documentation of the building and operation of the pile described bricks of (processed) Uranium Oxide (which the Oxygen in the Oxide would be similar in moderation capability as the graphite) and some Uranium. Phrase "neutron-producing uranium pellets" is scientifically inaccurate, doesn't appear in the documentation. Purified Uranium (with decay products found in ore removed) is essentially non-radioactive: the radiation counts for natural Uranium are masked by natural radioactivity from Cosmic Rays, Potassium-40, et al. U-238, 99.2752% natural abundance, radioactive half life is about the age of the Earth. Of the small number of Uranium atopms that do decay, most decay by alpha emmission and only less than .01% by spontaneous fission (which emits neutrons). A neutron source (Berylium/Polonium probably;Little Boy:"Polonium for the initiators") was introduced to initiate reaction, standard practice for all Uranium reactors. Plutonium on the other hand with a 24,000 yr half life and typically decays by spontaneous fission, is its own neutron source and does not need initiation. References: Shjacks45 (talk) 14:06, 4 November 2013 (UTC)
 * http://www.uchicago.edu/features/how_the_first_chain_reaction_changed_science/
 * http://www.osti.gov/accomplishments/documents/fullText/ACC0044.pdf includes "Fermi's own words" "initiator"


 * While that is the way I would do it, I cannot find a reference to the use of a polonium-berrylium (or polonium-radium) initiating source. The initiators used in Little Boy and Fat Man bombs were developed at los Alamos in 1944. I cannot find a reference to it in the sources you supply. Hawkeye7 (talk) 01:05, 25 March 2016 (UTC)

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Just a point of discussion. My father was part of, and possibly in charge of the navy detail at this reactor. Please Discuss the small navy security detail, and its report to the Pentagon. We have a family photo of him discussing the results with the Pentagon. He was a chief petty officer, later on the Bunker hill. Is this verifiable? His name was Louis F Haas. Till his dying day, he did not discuss this, but i know from his brother (who had security clearance in WW2) this was true. Thanks

daniel L Haas — Preceding unsigned comment added by 68.143.19.35 (talk) 18:00, 9 November 2017 (UTC)

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SCRAM axe-man story
The story that SCRAM referred to a "safety control rod axe man" is apocryphal and has no sources whatsoever. There are numerous sources for this being nothing more than an urban legend, I would like to point to this one in particular, where a historian apparently spoke to several scientists who were present the day of the test: https://public-blog.nrc-gateway.gov/2011/05/17/putting-the-axe-to-the-scram-myth/

I am confused about why the article seems to refer to the axe-man story as fact and refers to it in several places, without any sources. Sopwerdna (talk) 03:01, 27 May 2017 (UTC)
 * I cannot express how tired I am of claims that articles are unsourced when there are footnotes. Hawkeye7 (talk) 03:42, 27 May 2017 (UTC)

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Date format
Is there a good reason this article uses DMY dates like "2 December 1942" rather than MDY dates like "December 2, 1942"? The latter is suggested by MOS:DATETIES. —BarrelProof (talk) 05:13, 2 December 2017 (UTC)
 * The former is suggested by WP:MILFORMAT though, which I think applies here. --John (talk) 14:32, 2 December 2017 (UTC)
 * While I might have chosen American, and I think I and others did early on, the editor who did the most work to bring it up to good and featured chose Mil format, which seems not unreasonable, and it has been stable at that. Alanscottwalker (talk) 15:28, 2 December 2017 (UTC)
 * Thanks for the replies. I hadn't noticed the remarks about special treatment for military topics. —BarrelProof (talk) 04:24, 3 December 2017 (UTC)

MOS:UNIT
On a scientific article, why are we using imperial units first? To most of our target audience, degrees Fahrenheit are as useful as ells. --John (talk) 13:43, 2 December 2017 (UTC)
 * It's from the source. Rhodes didn't identify where he got it from, so there is a lingering suspicion in my mind that it was originally Celsius. I've flipped the display order.  Hawkeye7   (discuss)  20:19, 2 December 2017 (UTC)

1942
The fact that it fired in 1942 is major, and so should be in top of the lead. -DePiep (talk) 00:49, 3 December 2017 (UTC)
 * When it reached criticality is in the very first paragraph of the lead - that's top enough. Alanscottwalker (talk) 00:54, 3 December 2017 (UTC)
 * Why ever would one mention "first" without the era specififcation? -DePiep (talk) 00:56, 3 December 2017 (UTC)
 * Era? It's a thing.  Perhaps you mean World War II era, but that is also mentioned in the lead paragraph. Alanscottwalker (talk) 00:59, 3 December 2017 (UTC)
 * 1942 is major. Dec 2 is irrelevant (to lead). Really, dec 2 should not be in there. Time of X also relevant? No. -DePiep (talk) 01:03, 3 December 2017 (UTC)
 * 1942 is there in the lead, December 2 to be encyclopedic and give correct information (which is actually a date that every source states) is important. It is not the first reactor of 1942, it's not the first reactor of any one year, it's the first reactor of all the years, succinctly, it's the first reactor. Alanscottwalker (talk) 01:10, 3 December 2017 (UTC)

1942 only appears in sentence FOUR. How is that bring "first"? DePiep (talk) 01:10, 3 December 2017 (UTC)
 * Because we already said it was first in the same paragaph. Alanscottwalker (talk) 01:15, 3 December 2017 (UTC)


 * Hi. "1942" should be in the first sentence. Thank you. -DePiep (talk) 01:35, 3 December 2017 (UTC)

Incorrect equation in Design section
I'm fairly sure the equation for critical radius in the Design section is incorrect. The units don't even work. It's got length on the left and area on the right hand side. I can't seem to find the reference online, or I'd fix it myself. Could someone check this? Fcrary (talk) 21:35, 6 December 2017 (UTC)
 * I have the book here. The formula is correct; it is the next line that is in error. M is the average distance that a neutron travels before it is absorbed. I have corrected the article.   Hawkeye7   (discuss)  23:52, 6 December 2017 (UTC)

Partially missing motivation
Having just finished a biography of Meitner by Rife, one observation I had about the introductory paragraphs/sections is that the basic motivation behind the pile was the wartime panic and the thought that the Nazis would get an atomic bomb. This was a serious driving force behind the quick developments, together with a healthy dose of early self-censorship to keep the basic facts of nuclear processes away from the Nazis. Most of the immigrant scientists were Jewish (or in the case of Fermi had Jewish family) and knew both the science and the situation in Europe. The article could use a bit of development to indicate this panic, the pressure to develop a weapon first, and the need for secrecy. The Curies were asked not to publish their results, but they published on the chain reaction anyways in 1939 - perhaps the last open publication on that subject until after the war. Their lab was subsequently shipped wholesale to Germany, I believe.

The Hahn-Meitner story and fission is complicated, of course. The collaboration was still in place in December 1938, however, with Hahn repeatedly asking Meitner for help with interpretation. The theoretical analysis on fission was done in December 1938 (on a walk in the Swedish woods), but for awkward reasons, the beans were spilled and the paper's publication was delayed. So you had the Columbia experiment going already in January 1939 before the Meitner-Frisch paper appears (because Bohr had an advance copy of their paper that he had brought across the Atlantic on a ship, etc.) - the instant excitement in the U.S. was due to the Meitner-Frisch physical explanation that had been leaked. In any case, I think we should strive to show that Meitner gets proper credit for the discovery, Nobel Prize oversight notwithstanding.

The article I've been working on is Discovery of the neutron, which may warrant a "See also" from this article. Bdushaw (talk) 10:53, 27 December 2017 (UTC)


 * Glad to see someone working on it. It's only worth a sentence here, but I was struggling to get the sentence right. I wanted to say that Meitner and Frisch explained the results in terms of fission. The actual mechanism, of fission was explained by Bohr and Wheeler.  Hawkeye7   (discuss)  11:42, 27 December 2017 (UTC)


 * I've been hesitant to dive into this article, but I may have some time now. I would like to rework the two initial sections, perhaps - but I'm still hesitant.  What I have in mind would reduce these sections to a construction zone for a time, and I would likely need assistance in writing and sorting out the details.  From what I understand, the origins/motivations as described in this article are not quite right.  I will hold up for now to wait for a bit of comment; I dislike disrupting a Featured Article.   I note that the biography I was reading (The Pope of Physics by Segre' and Hoerlin, 2016) called this reactor "Critical Pile 1"...I suspect that was the name Fermi gave it, revised later; practically all references I could find had "Chicago Pile", but nevertheless I think "Critical Pile" has merit.  This video on youtube on Fermi's life:
 * https://www.youtube.com/watch?v=g3SKBwzTtv0
 * has quite a bit of original material relating to CP-1; perhaps a link from this article?  So much of this reactor was all Fermi...and a remarkable set of coincidences to bring people, funds, and urgency together at one time and place to get it to happen (if Fermi had stayed in Rome, would this reactor have happened?  I have my doubts - this just to emphasize the importance of Fermi to the project).  The Szilard letter is often cited, but it seems the avenues for funding occurred elsewhere.  And a myriad of other "adjustments"...  Bdushaw (talk) 08:10, 4 June 2018 (UTC)


 * That's not permitted in a Featured Article, where bold changes are generally considered disruptive editing. Post proposed changes to the talk page. There's no evidence that it was ever called "Critical Pile 1". The reactor would have been achieved without Fermi. Remember that Eugene Wigner had already produced a design for the production reactors. What happened to Discovery of the neutron? Most of it is still unreferenced. It needs a lot of work.  Hawkeye7   (discuss)  10:37, 4 June 2018 (UTC)
 * Yes, please post proposals here first. It is not usual to reject multiple sources connections, for example of Slizard, to government funding, to building. Rejecting the usual name also has no basis. Alanscottwalker (talk) 10:54, 4 June 2018 (UTC)
 * Well, I am glad I posted the inquiry first. I have no agenda here - just sorting through what I know and learned, hoping to reach a consensus regarding the origins of the reactor.  (I would never make the argument that CP-1 would never have happened without Fermi; not relevant to the article; I did, however, want to emphasize the major, central role that Fermi played.)  Some of what is missing is described in the Discovery of the neutron article (a Good Article - "Most of it is unreferenced"?) - viz the discovery of isotopes and the recognition by Eddington that nuclear processes may power stars.   Early on, the magnitudes of energy were astonishing to people.  There is the famous quote from Rutherford to the effect that anyone expecting to get energy out of nuclear processes is "talking moonshine" (mid-1930s?).  Then the article does not mention the 200 MeV energy released by Uranium fission, a quite large, astonishing number determined by Meitner and Frisch (the former still collaborating with Hahn).  There is the anecdote, Feb. 1939?, of Fermi looking out over New York City and describing the effects of what the hypothetical bomb would do.  And as mentioned above, there was real panic among the people involved regarding the Nazis and the outbreak of war - creating pressure to build the bomb ASAP and pressure to keep things secret - the article makes no direct reference to this alarm.  A lot of these people were just arrived from Europe - Fermi had only arrived in New York at the end of 1938 after winning the Nobel Prize; things were happening literally fresh off the boat (the article reads like Fermi was a well established scientist at Columbia!).  "Critical Pile 1" does have a citation, which I gave it, a quite solid citation, though it is certainly not common - I wasn't suggesting to rename the article, just perhaps a "sometimes called..."; finding at least one other good citation to that name would be helpful.  Plutonium was conjectured also by Norman Feather and Egon Bretscher; one of those simultaneous discoveries, fortuitously the two groups had selected the same name for the element (Neptunium, Plutonium).  Szilard is a curious character - I am somewhat concerned about undue weight on him in the article. CP-1 was all about the bomb; the reactor was just a prerequisite to developing a bomb - there was no sense of nuclear energy for society or let's try this cool experiment to see if we can get a sustained reaction; it was necessary to get to bomb development.  Just a few of the...nuances...to sort through.
 * Perhaps I should copy the first two sections of the article, say, to a sub-page on this Talk page or someplace and work with you all on revising the sections? Bdushaw (talk) 18:04, 4 June 2018 (UTC)
 * Yes, the talk page would be best. Responding to your points:
 * The Discovery of the neutron is largely unreferenced, and therefore its Good Article status would not survive a Good Article review. Such articles must be fully referenced with inline citations. (fix it up.)
 * I am baffled and befuddled by this statement - the article is well referenced and has had a Good Article review, passing with flying colors. Bdushaw (talk) 03:45, 5 June 2018 (UTC)
 * Eddington theorised that stars were powered by nuclear processes. Carl Friedrich von Weizsäcker and Hans Bethe described the processes involved. This put everyone (especially Szilard and Fermi) on the wrong track, with the assumption that nuclear reactions were most likely with the light elements. Because it refers to fusion and not fission, this is omitted from the article. In the articles, we try to keep the background down to the minimum necessary to describe the subject of the article, and keep the article focused on the subject.
 * The general point was that people recognized early on there were huge amounts of energy lurking within nuclei. The article needs to make this point. The difference between energies from the chemical reactions people were familiar with, and nuclear reactions is a factor of about a million. The article is missing this point. Bdushaw (talk) 03:45, 5 June 2018 (UTC)
 * Yes, Rutherford famously rejected the possibility of nuclear energy; but this was before even the discovery of the neutron.
 * 1933, I think, after the discovery. The point being, that although Szilard was taking patents, etc., most of the physicists did not think that energy from nuclei was possible anytime soon. This general view set the stage for the shock of the discovery of fission. Bdushaw (talk) 03:45, 5 June 2018 (UTC)
 * You're quite right. Rutherford still has his defenders though. Meitner and Frisch calculated that a fission produced about 200 MeV. It wasn't useful though unless a chain reaction was possible.  Hawkeye7   (discuss)  08:05, 5 June 2018 (UTC)
 * Alarm was mostly evident among scientists who were refugees from fascism and nazism, but most scientists did not believe that a bomb was practical.
 * I was going to add words to this effect, but my problem was this: does Szilard count as a refugee scientist?  Hawkeye7   (discuss)  08:05, 5 June 2018 (UTC)
 * Fermi was one of them at the time. The idea of using the reactor to produce plutonium came from Berkeley and, independently, from Cambridge. At the time, Fermi did not believe that Bohr and Wheeler were correct.  Hawkeye7   (discuss)  08:05, 5 June 2018 (UTC)
 * Contemplating plutonium, the question crossed my mind as to the relevance of plutonium to the CP-1. Was the one aim of the reactor to create plutonium?  The question was whether it may make sense to remove the plutonium discussion altogether as not directly related to CP-1? Bdushaw (talk) 03:45, 5 June 2018 (UTC)
 * The CP-1 reactor was a proof of concept. It was followed by the X-10 reactor, a pilot plutonium production reactor, and it in turn by the production reactors at Hanford. It was important though. Without the impetus to produce plutonium for bombs, there would have been no Manhattan Project interest in reactors. Without its AAA priority, Fermi and Szilard would not have been able to obtain the scarce materials they needed, to say nothing of permission to build a reactor in downtown Chicago.  Hawkeye7   (discuss)  08:05, 5 June 2018 (UTC)
 * Thinking about some changes to address your points.  Hawkeye7   (discuss)  21:47, 4 June 2018 (UTC)

edits to lead
I've made some edits to the lead. The previous version had a lot of information that was not particularly relevant (e.g., weights of materials given in multiple units of measure), and lacked a lot of information that was needed in order to put the project in perspective and explain its significance. For example, it had lacked any mention of the fact that the uranium was not enriched.--76.169.116.244 (talk) 05:02, 25 January 2019 (UTC)

Natural
If we need a note to the lead make a note about what occurred billions of years ago make a note, but not that undue digression for this article. Alanscottwalker (talk) 22:29, 9 August 2019 (UTC)


 * What's the problem with the earlier suggestion, simply stating that the Chicago Pile was the first "artificial" reactor? A reactor is simply defined by an enhanced fission rate caused by the neutrons from other fissions. That can, or could a long time ago, happen naturally. So the Chicago Pile was not the first nuclear reactor. Adding the one word, "artificial", would address that without any digression. But for some reason, you seem to strongly object to that. I don't understand why. Fcrary (talk) 22:44, 9 August 2019 (UTC)
 * This article links to nuclear reactor: "A nuclear reactor, formerly known as an atomic pile, is a device used to initiate and control a self-sustained nuclear chain reaction.
 * A "reaction" is what you describe, a nuclear reactor is what they made in the 40s and then theorized in the 50s, that because it used a scarce natural element, in a past time when that element was abundant a similar process to what happened in a nuclear reactor could occur, later found.to have occured billions of years ago.
 * But, although it makes the sentence a bit bizarre, in effect saying it's an artificial artificial device, I will grudgingly not stand in the way. Alanscottwalker (talk) 22:56, 9 August 2019 (UTC)
 * But, although it makes the sentence a bit bizarre, in effect saying it's an artificial artificial device, I will grudgingly not stand in the way. Alanscottwalker (talk) 22:56, 9 August 2019 (UTC)
 * But, although it makes the sentence a bit bizarre, in effect saying it's an artificial artificial device, I will grudgingly not stand in the way. Alanscottwalker (talk) 22:56, 9 August 2019 (UTC)


 * I agree that the claim that CP-1 was the first nuclear reactor is inaccurate and needs a caveat. See what you think of my edit (made before I saw this discussion). NPguy (talk) 02:45, 10 August 2019 (UTC)


 * Given the definition of a reactor as a device used to initiate and control a self-sustained nuclear chain reaction, the natural reactions that occurred millions of years ago are not considered reactors.  Hawkeye7   (discuss)  03:28, 10 August 2019 (UTC)


 * And yet the Nuclear reactor article has a section on and a link to Natural nuclear fission reactor. Seems like there may be a problem in the definition in the lede of the nuclear reactor article. 17:01, 10 August 2019 (UTC)
 * Not in the least, it only takes a modicum of ordinary intelligence to understand that when nuclear reactors are discussed they are the devices created and used by humans, which is fundamentally a different endevour then billions of years ago a natural event in the earth's crust occurred that has similarity to what occurs in the things that were already created by humans, when that natural event was theorized about and then confirmed. Alanscottwalker (talk) 17:24, 10 August 2019 (UTC)


 * Your claim is essentially linguistic rather than substantive. Given the widespread use of the term natural nuclear reactor, you seem to have lost the argument. NPguy (talk) 17:27, 10 August 2019 (UTC)
 * Not widespread in the least. A very small niche in perhaps some fanboyism or lack of imagination or lazyness, has gone to elide what was always meant to be, 'like/similar to a nuclear reactor',  departing from common meaning and English dictionaries.  Alanscottwalker (talk) 13:26, 11 August 2019 (UTC)


 * It's probably moot at this point, but I think that's correct. If you look at the references in natural nuclear fission reactor, they use the term "reactor" to the exclusion of any other term. And those are papers, both research and review, published in places like Scientific American, Physical Review Letters, Physical Reviews C, etc. All widely considered to be reliable sources. I wouldn't call their editors "fanboys" or "lazy." Now, it's quite possible the original discoverers intentionally introduced an odd term, either as branding or to attract attention. That wouldn't be the first time a scientist did that. Or, since the discoverer was French, "réacteur" may not have exactly same connotations as "reactor" does in English. Again, scientific terminology is full of oddities from glitchy translation. But, regardless of the origins, "natural reactor" seems to be the accepted term in the literature, so we're stuck with it. Fcrary (talk) 18:32, 11 August 2019 (UTC)
 * But what you say does not actually contradict the concept it being just the eliding of 'like/similar to a nuclear reactor.' So, natural reactor, because common English encyclopedia/dictionary for 'nuclear reactor' is a machine or device, designed and used     So if you are going to say something is like a nuclear reactor but not the common understanding (that people invent, design and use), it needs a modifier, 'natural'. Just like if one is talking about a clock, but not the common meaning of clock and what is really being expressed is 'in ways like a clock', one says 'biological clock'  -- Alanscottwalker (talk) 14:57, 12 August 2019 (UTC)


 * Nuclear reactions can be many things, including a spontaneous decay releasing a beta particle. "Reactor" specifies a particular type of reaction. I don't see "artificial reactor" as redundant, any more than "natural reactor" is a contradiction in terms. "Artificial" may sound like poor wording to some, but to others it is an important qualification to "first." However, a discussion of Oklo does not belong in the lead of an article on the Chicago Pile. I've put a link in under "Also see." Fcrary (talk) 17:48, 10 August 2019 (UTC)
 * Thanks for removing the irrelevant, wholly undue note on Oklo, and I said I would accept the artificial word, although it's still odd, and we don't have to discuss the rest, which is plain meaning. (Also, perhaps I needed to be clearer in my first reply or just spelled it out longer: 'A type of "reaction" is what you describe') -- Alanscottwalker (talk) 19:09, 10 August 2019 (UTC)

So "fanboy" is a gratuitous insult, and reflects a parochial view that the only real reactors are those designed by nuclear engineers. In the scientific community (physics, geology), Oklo is well known as a natural reactor. I'm open to compromise on how to explain the qualification that CP-1 was the first artificial reactor, but the "see also" link is clearly insufficient because it is disconnected from the use of the term and its presence is unexplained. NPguy (talk) 03:09, 14 August 2019 (UTC)
 * Your putting this note in the lead has been rejected by multiple editors as undue, Oklo had absolutely nothing whatsoever to do with CP-1. There is nothing parochial about common and encyclopedic English,    that's what makes it common, not parochial at all, it's broad. It's your argument that is arguing for the parochial niche. And your insistence on digression is terrible writing and irrelevant. To the extent anyone wants information on reactor that's why link is provided in the first sentence but the purpose of this article is not that purpose, this article is not reactor.  If you wish to take the other link out of the 'see also', since that was also part of the editorial compromise, don't, it's against consensus.-- Alanscottwalker (talk) 11:41, 14 August 2019 (UTC)

Some explanation is needed. If you don't want it in a footnote to the lede (where is't not really that that prominent or distracting) and "see also" is insufficient, maybe you can suggest another place for it. NPguy (talk) 02:14, 16 August 2019 (UTC)
 * No, the next sentence ("the first human-made self-sustaining nuclear chain reaction was initiated in CP-1") explains it fine, enough. Alanscottwalker (talk) 02:22, 16 August 2019 (UTC)
 * It doesn't explain it. It just repeats it.  It doesn't explain that there's another kind.  Since this links to the nuclear reactor article I placed a cross-reference at the top of that article, where it is a better fit. NPguy (talk) 02:31, 16 August 2019 (UTC)

University of California vs. University of California, Berkeley
I recently made an edit to the page changing "University of California" to "University of California, Berkeley", because UC Berkeley is no longer referred to as the "University of California", which only refers to the university system. This edit was reverted by {u|EEng}.

Historically, UC Berkeley was referred to as the University of California, but since its renaming in 1958 and the founding of the University of California (the school system), Berkeley is no longer referred to as the University of California. Doing so is ambiguous and incorrect. This is why I made this edit.

The passage in question refers specifically to UC Berkeley because, at the time, the University of California was UC Berkeley. Emilio Segrè and Glenn Seaborg were not scientists in the UC system, they were scientists at UC Berkeley.

I know anecdotal evidence isn't suitable for an encyclopedia, but after living in California for 18 years, doing research with some of the UCs, applying to UC Berkeley itself, I can say for certain that UC Berkeley is not called the University of California. All of this can be verified by reading the sources, or knowing anything about the way the university system in California works. 20:38, 9 November 2019 (UTC)
 * The problem with those edits is that, at the time of the events in question, the university was simply the "University of California." Those events predate the formation of the UC system.  So the edits are anachronistic.  Best to have the embedded link to UC Berkley but have the text refer simply to UC. NPguy (talk) 20:56, 9 November 2019 (UTC)
 * That's a fair point. I still think that it is ambiguous and should be referred to as UC Berkeley within the text of the article.   21:13, 9 November 2019 (UTC)
 * Well I grew up in Berkeley, attended Berkeley, and briefly taught at Berkeley; my mother graduated from Berkeley (twice) and worked for Berkeley; and my uncle was the budget director for the entire UC system. So I can assure you that you don't know what you're talking about, not least in your reference to its renaming in 1958 and the founding of the University of California (the school system). There is one president, one board of regents, and – though the phrase University system lends bureaucratically desirable ambiguity on the question of whether each campus is itself a "university" controlling its own affairs – one university. EEng 20:57, 9 November 2019 (UTC)
 * The problem with referring to it as the "University of California" is that it is ambiguous. Most readers will not understand that it is referring to Berkeley specifically. The research was done through UC Berkeley and not through the university system.   21:13, 9 November 2019 (UTC)
 * And most readers will not understand that "University of Chicago" refers to a football stadium. So what? EEng 21:21, 9 November 2019 (UTC)
 * I'd argue that you should specifically refer to the University of Chicago football stadium rather than just calling it the University of Chicago, since it is also ambiguous. Wikipedia is supposed to be an encyclopedia, and as such, it should be as unambiguous as possible.   21:24, 9 November 2019 (UTC)
 * Well, I don't intend to say all the ways I know Berkeley, but my editorial opinion for this article is 'University of California' is just fine for old Cal. Alanscottwalker (talk) 21:31, 9 November 2019 (UTC)
 * I think that's fine for normal conversation, but in an encyclopedia we should try to be unambiguous.   21:33, 9 November 2019 (UTC)
 * It is unambiguous enough already. -- Alanscottwalker (talk) 21:47, 9 November 2019 (UTC)
 * According to College and university article advice, under College and University Articles, point 5 states that "For universities that are part of a larger system, in general the university name is followed by a comma and the name of the city in which the institution is located. For example, University of California, Berkeley and University of California, San Diego." This makes it pretty clear that it should say University of California, Berkeley.   21:33, 9 November 2019 (UTC)
 * No. Although your link is wrong, that's an article title convention, we are not talking about article title, we are talking about running prose.  In running prose no need to stop the flow by adding this unneeded detail.  Alanscottwalker (talk) 21:40, 9 November 2019 (UTC)
 * Oh, that's a good point. I still think that it should be referred to as UC Berkeley in the text. I understand that many people will understand that it refers to Berkeley, but not everyone is from California and not everyone understands that the University of California is not the name of any university. Personally, I also think it gives off connotations that Berkeley is the UC and all others are inferior, but that might just be because I'm tired of Berkeley kids acting all high-and-mighty (not referring to you, EEng, just my personal experience). The UCs in other articles are referred to specifically using their campus, and it isn't exactly clear whether or not this article is referring to the UC system or the Berkeley campus.   21:47, 9 November 2019 (UTC)
 * Well, actually, Berkeley is unambiguously the elite among the UC campuses, like it or not. And don't worry about hurting my feelings -- my degree's from Harvard so I get my high-and-mighty that way. Anyway, why not always specifically say that work was done not just at UC, not just UC Berkeley, but specifically in the UC Berkeley Physics department? We don't want people thinking it was all of UC Berkeley when it was really just this or that department. EEng 22:13, 9 November 2019 (UTC)
 * The article does not need any of that detail. It's difficult to see anyone actually going, 'oh my god, it's Berkeley, I'm so confused' --nothing about the actual context requires such minutia of geography, nor organizational history.  Alanscottwalker (talk) 22:23, 9 November 2019 (UTC)
 * For my entire life, UC has referred to the university system, and not UC Berkeley specifically. Had I not known already that the research was done at Berkeley, I would have thought that the UC system itself did the research. We're also not getting into minutia here, that's quite a bit reductive. It's literally just the name of the campus.   23:11, 9 November 2019 (UTC)
 * The sentence is not talking about your life, it's talking about other peoples lives in 1940. This was the University of California in 1940, the organizational chart that developed since does not change that. It's wholly unreasonable to think that the University of California did not exist in 1940, and it's literally fine if you think the University's organization did the work, the university's organization did do the work. The University of California, however you in particular think about it, traces its history to 1868. -- Alanscottwalker (talk) 13:49, 10 November 2019 (UTC)
 * As others have noted, this is an historical article. The usual practice is to use the names which were used at the time of the events described. German nuclear research in 1930s and 40s was conducted at the Kaiser Wilhelm Institute. No one says it was done at one of the Max Planck Institutes, despite the fact that that's what KWI was renamed after the war. If we insisted on the current names, we'd probably have to say most of the work in question was done at Lawrence Berkeley National Laboratory (the Radiation Laboratory was up the hill where LBNL currently is, not on campus.) And, a contemporary event, I guess military historians would have to talk about the Battle of Volgograd. That would be seriously anachronistic. Fcrary (talk) 22:39, 9 November 2019 (UTC)
 * That's a fair point. Maybe we could change it to "University of California (now known as University of California, Berkeley)" as a decent middle ground, or LBNL as you suggest.   23:11, 9 November 2019 (UTC)
 * I wasn't suggesting we use LBNL. I was pointing out how anachronistic it would be. Ernest Lawrence never worked at a laboratory named after himself. His name didn't get attached to it until after his death. Implying otherwise would just be weird and confusing. I wouldn't complain too much about the parenthetical, but I think it's unnecessary. The link points to the article on UCB and this is an article on the Chicago pile. The word "California" only appears twice, so this level of specificity about UC campuses may be a bit much. Or perhaps call it the "University of California's Radiation Laboratory", since that's what it was called at the time and doesn't imply the whole UC system. Fcrary (talk) 00:33, 10 November 2019 (UTC)
 * University of California Radiation Laboratory is an existing redirect and is indeed the right thing to use. (And I see the COMMA BERKELEY forces have been at work there as well .) E<b style="color: blue;">Eng</b> 01:16, 10 November 2019 (UTC)

Neutron Count Doubt
Hallo!: If Neutrons are 'discrete' particles, meaning it exist in units, not in fractions of units: How can be said a Uranium atom emits in fission an average of 2.4 neutrons? You can indicate this type of figures as an average for a mass of several atoms, but from a single atom, simply, neutrons can not be fractioned, or exploded, or smashed or cut or broken. Could it? Blessings +
 * It's an average dude. Hawkeye7   (discuss)  11:22, 1 October 2021 (UTC)
 * To be more specific, a uranium atom can fission in several different ways and they don't produce the same number of neutrons. Any one of those reactions only produces an integral number of neutrons. But when you average over all the reactions, weighted by their probability, you get a non-integral number of neutrons. Fcrary (talk) 18:01, 1 October 2021 (UTC)