Talk:Nuclear fusion

message: With billions being spent on the effort, there should be a separate section about the ongoing research in that area. The article does mention this, but only embedded in sections on pure science. 
Sean7phil (talk) 19:55, 29 November 2009 (UTC)
thread_title: Needs Section on Development for Commercial Use

message: I've read the article about Nuclear fusion (shouldn't that be either "nuclear fusion" or "Nuclear Fusion") and have faied utterly to understand where the energy actually comes from. 
Perhaps a few sentences that make it more explicit would be helpful for those of us who aren't physics experts. 
Also, as was mentioned elsewhere in this discussion, much of this is about how to generate power from nuclear fusion when it sould be about how fusion itself works. 
Thanks
Dave
Davemenc 04:01, 27 November 2005 (UTC)
replies: text: Matter can be organized in different ways. Some of those ways are more stable than others. Unstable states are unstable because they have a lot of potential energy. If you take some matter and reorganize it into a more stable state, that potential energy is released. In fusion, deuterium (hydrogen-2) and tritium (hydrogen-3) are not as stable as helium and a neutron, so the reaction D + T -> He + n releases energy (the products come out of the reaction  moving much faster than the reactants went in). We capture that energy as heat and use it to generate electricity. Canonymous 18:04, 15 September 2006 (UTC)
replies: text: Isn't the plain English explanation just that a small part of the reactant mass ceases to exist as matter? It's converted into energy. It's a small portion, to be sure, as opposed to antimatter, where 100% of reactants are converted into some form of energy or neutrinos, with no quarks left to tell the tale. Sacxpert 10:48, 17 November 2006 (UTC)
replies: text: This does happen, but isn't the reason. Consider someone asking how a flashlight battery works. As with all cases, as the stored energy decreases, the mass decreases, but that doesn't explain the chemical reactions that cause the mass change. In both the battery and fusion reaction, the products have a lower (free) energy, making energy available for our use. Gah4 (talk) 09:04, 5 September 2017 (UTC)

text: Fission products have lower potential (nuclear) energy than the input U235. They normally have more neutrons than the more stable nuclide with that number of nucleons. Some neutrons are released in fission, but not enough for the products to be most stable. Gah4 (talk) 09:04, 5 September 2017 (UTC)
replies: text:  The absorption of a neutron places some nuclei into an "invalid" quantum state; the nucleus reacts to this illegal rearrangement by "vibrating" itself into valid smaller nuclei, after throwing away various items, including x-ray photons and more neutrons. Which nuclei? Big ones, where the outer nucleons are "far" from the center of the nucleus, and at these vast distances, the outermost nucleons feel a weaker nuclear force- recall, the nuclear force works only at short distances. -Dawn McGatney 69.139.231.9 (talk) 13:04, 1 April 2008 (UTC)

text: A large part of the "mass" of a proton already "is" energy from the beginning: The sum of the masses of the three quarks of which the proton consists only make up about 10% of the total mass of a proton, the rest is "field energy" from the strong force's field. So you have a large pool of energy to draw from in fusions. It's similar to an asteroid falling on Earth, which also produces lots of energy without destroying any particles from either the asteroid or the Earth: there the energy comes from the loss of gravitational energy of the asteroid in Earth's gravitational field. Hope this helps.--Roentgenium111 (talk) 16:25, 22 April 2009 (UTC)
replies: text: Similar to the stability of noble gases, with their full electron shells, the alpha particle (He4 nucleus) has full nuclear shells. The binding is especially strong for alpha. There can be two (opposite spin) protons in the first proton shell, and two neutrons in the first neutron shell. The best model for alpha decay of heavy nuclei is that alpha particles are moving around at high speed (the Fermi velocity) inside, and eventually tunnel out. They tunnel as a bound state, similar to Cooper pairs in superconductors tunneling through a Josephson junction. Gah4 (talk) 09:04, 5 September 2017 (UTC)

text: BTW: I suppose you mean "fission" in your 2nd sentence? --Roentgenium111 (talk) 16:25, 22 April 2009 (UTC)

text: The title is a sentence (or something like one).  Nuclear fusion.  Midgley (talk) 16:54, 22 April 2009 (UTC)
replies: text: For quantum mechanical reason, the alpha particle (Helium nucleus) is especially stable, for similar reasons to the chemical stability (inertness) of Helium. Two protons (with opposite spin) and two neutrons (also with opposite spin) pack very tightly, minimizing the quantum exchange energy. They are so tightly bound, that larger nuclei can be considered as having alpha particles moving around (at the fermi velocity), and alpha decay occurs when one tunnels out of the nucleus. Fundamentally, it is the result of the quantum mechanical exchange interaction (sometimes called exchange force). There is no classical analog, and no easy way to explain it. It is related to indistinguishability, which also has no classical analog. Gah4 (talk) 23:35, 15 March 2019 (UTC)
thread_title:  But where does the energy come from? 

message: Sigh. The main image has been replaced by an animation. Though I know we are supposed to say "hooray" for anyone who takes the time to make an animation, can I state that:
#It takes 23 seconds to watch the whole animation to figure out what happens. A diagram can be understood basically instantly. (Consider that there are even ways to do this better by means of animation. This page has a DT reaction that basically takes 4 seconds and is just as easy to understand.)
#The animation does nothing other than showing two things coming together and a third thing coming out of it. Again, a diagram can do this much more efficiently.
#The animation portrays the "energy" released as a circular yellow beam. This is misleading. Most of the energy out of that particular reaction is in the kinetic force of the neutron that is being released and the kinetic force of the alpha particle. This makes it look like the "energy" is some sort of separate thing from the byproducts of the reaction, which it is not. In any case it leaves out a lot of the energy. The neutron goes off with 14.1 MeV, while the alpha particle, rather than staying still in the center, flies off with a kinetic energy of 3.5 MeV. 
I'm sure the image took a long time to make, but is it really the best means of expressing this particular reaction? There are some things that animations are indispensable for and much better than static diagrams (the Two-stroke engine page is a great example of this—complicated movement of materials that must be explained in many frames = great for using an animation!). I'm not sure that simple nuclear reactions are among them (seeing the two atoms tediously run into each other presents no additional information, takes a lot longer). I personally think a diagram (like this one) is a lot clearer. It gets the same information content across in a much more clear and concise manner. In this particular case, the animation is even misleading in terms of the mechanism and amount of energy released. --98.217.8.46 (talk) 02:01, 27 October 2008 (UTC)
thread_title: Image

message: It may be possible to reduce the temperature requirement for plasma formation by inducing temporary dipoles in the deuterium and tritium gas via microwave radiation.  This is the same theory behind the formation of ball lightning and can be easily replicated.  The modifications would be minimal, and plasma damage to the inner wall would be less extensive.  —Preceding unsigned comment added by 66.66.118.233 (talk) 18:45, 8 June 2009 (UTC)
thread_title:  possible fusion shortcut 

message: The following (Overview, end of paragraph 3) is not a sentence, but fragment lacking a verb: "However, the creation of workable designs for a reactor which will deliver ten times more fusion energy than the amount needed to heat up plasma to required temperatures (see ITER which is scheduled to be operational in 2018)." --RDK
In the "Nuclear fusion in stars" section, the sentence "The net result is the fusion of four protons into one alpha particle, with the release of two positrons, two neutrinos (which changes two of the protons into neutrons), and energy" should have its parenthetical clause moved to follow "positrons" rather than "neutrinos", in order to avoid giving a mistaken impression.  Revised version "The net result is the fusion of four protons into one alpha particle, with the release of two positrons (which changes two of the protons into neutrons), two neutrinos, and energy" would more appropriately signal that it is the release of charged positrons, not neutral neutrinos, which is associated with the proton-to-neutron changes. 69.95.141.252 (talk) 02:24, 14 September 2015 (UTC)
replies: text: There is no need to do that, because the emission of the positrons and neutrinos is exactly simultaneous, and certainly it is not one emission over the other than accomplishes the conversion of up-quark to a down-quark. Technically, it is the emission of a virtual W+ boson that changes proton to neutron. Then the W+ boson decays into a positron and electron neutrino.  By the way, the sentence as written vaguely implies that the Sun generates positrons by this process. Of course it does not. The two positrons annihilate with two electrons in the ionized core, and are converted to gamma rays. Charge is conserved in all of this, so that 4p+ and 4e- (neutral) are converted to 4He + 2e- (neutral). If not for the ionization it would be (net reaction) that 4 hydrogen atoms are converted to one helium plus gamma rays and two neutrinos. Forget the positrons. SBHarris 04:49, 14 September 2015 (UTC)
replies: text:  Thank you. Richard B. Woods (talk) 05:28, 14 September 2015 (UTC)
thread_title:  editing required 

message: Muon catalyzed fusion is mentionned as a confinement method. This is strictly spoken not correct. Muon catalyzed fusion can occur always, irrespective of the confinement method.
(I don't feel qualified to attempt to edit.) -- AvdH.
:Well, it does get specific nuclei together, so small scale confinement. Gah4 (talk) 03:01, 31 January 2017 (UTC)
thread_title:  muon catalyzed fusion 

message: A better way to teach this subject is from the stand point of Chemistry & the Periodic Table. The reason being that the system of filling electron orbital bears a direct relationship with the nucleus. Using the understanding of chemical bonding extends the creation of intermediate steps or bond formations, etc. Which extend into the nuclear aspect of the bonding orbitals (S, P, D & F)& how great role they play in nuclear chemistry. Basic electron in its orbital form implies the nucleus aspect that form is an required to be 'stable' element.  —Preceding unsigned comment added by 72.184.40.168 (talk) 08:48, 14 August 2009 (UTC)
thread_title:  Trail Offer: Chemistry & the Periodic Table. 

message: I recommended to add more data on that table, such as the temperature in kelvin (K) relative to the electron volt (ev), and the data for Lithium 6 Deuterium (Li6D) reaction as well.  —Preceding unsigned comment added by 203.59.13.178 (talk) 01:24, 18 October 2009 (UTC)
replies: text: After reading Richard Rhodes' book "The making of the Atomic Bomb" We can say that "we have done that". And  in Kaplan,s "Nuclear Physics" book tells us that we did lithium7 plus proton fusion prior to 1933. But we seem to be stuck on fast neutron generation technology.WFPM (talk) 18:48, 13 March 2010 (UTC)
thread_title:  More Data at Table: Temperature, Lithium 6 Deuterium ?

message: Just a minor point. The article states "208 nucleons, corresponding to a diameter of about 6 nucleons" in the 4th paragraph of the requirements section.
I may be completely on the wrong track here, but it seems to me that if a nucleus is roughly spherical (which I am pretty sure is true, and if not it's pointless to talk about its diameter) then you should be able to get an approximation of the total number of nucleons with 4π/3 * r^3.
If you have a diameter of 6 nucleons (thus r = 3), that gives roughly 38 nucleons total. Which seems to disagree with the article.
If you take the diameter as 7 nucleons (r = 3.5), then you end up with more like 180, which is significantly closer to 208
Might be splitting hairs, but it was just something I noticed.
BackStabbath (talk) 01:14, 3 February 2010 (UTC)
replies: text: If you want the ratio of the radii (or diameters) of two spheres, one of which is 208 times the volume of other, the ratio is 208^(1/3) = 5.92. The sphere with 208 times the volume will have almost 6 times the linear dimensions of the other. The constants in front drop out of these ratios. That factor is what you're adding, but shouldn't. SBHarris 01:56, 3 February 2010 (UT
If you furthermore want the ratio of diameters of a sphere packing process you have to increase the spherical volume size to accommodate the unfilled volume by about 35% and thus the spherical diameter by about 10% which in this case argues in favor of a 7 diameter multiple. But if you want to take into consideration the proposed volumetric independence of each sphere for spin compatibility purposes you also need to conceptualize a larger volume. Also, if you're willing to consider other accumulation configurations, such as cylindrical configurations as a means of accumulation consideration, you might consider the accumulation configurations shown in my nuclear model image in Talk:nuclear model. You might note that in his book "General Chemistry" Dr Linus Pauling showed images of spherical packing atomic models as "hypothetical models" with a degree of skepticism.WFPM (talk) 18:14, 13 March 2010 (UTC)
replies: text: No. It is usual to picture a nucleus as a ball of protons and neutrons packed together. Note that Pauli exclusion applies to protons and neutrons separately, such that two (opposite spin) protons and two (opposite spin) neutrons can pack as one. They are still quantum objects, and so somewhat fuzzy, but not as fuzzy as electrons in atomic shells. The actual requirement is to fill up shells satisfying Pauli exclusion, with additional nucleons having higher and higher Fermi energy, and so Fermi momentum, which, with Heisenberg uncertainty, determines the size. Consider also the sizes of atoms as atomic number increases. Gah4 (talk) 09:28, 5 September 2017 (UTC)

text: It is common to describe nuclei, not by diameter but by area, called cross section. If you shoot a neutron, for example, at a nucleus, the cross section is the area that describes the chance of hitting (interacting) with the nucleus, as it might for a neutron to go through a hole with that area. Because of the large de Broglie wavelength for slow neutrons, use the fast neutron cross section. The unit barn is commonly used for nuclei cross section. Gah4 (talk) 00:28, 16 March 2019 (UTC)
thread_title:  Nuclear diameter 

message: "Only direct conversion of mass into energy, such as that caused by the collision of matter and antimatter, is more energetic per unit of mass than nuclear fusion."
Aren't blackholes also more efficient at converting mass into energy? Malamockq (talk) 20:12, 23 April 2010 (UTC)
replies: text: Conversion of mass into energy is an erroneous phrasing/misconception/confusion, the mass does not convert into energy.--79.116.78.65 (talk) 20:10, 11 September 2010 (UTC)
replies: text:  That is correct. Matter can be converted to energy. Which is to say: particles considered matter can be converted to particles not considered matter (as when electrons and positrons are coverted to photons). But in this process, mass is conservered. Both matter and energy retain their mass, which cannot be created nor destroyed. SBHarris 01:26, 16 October 2010 (UTC)

text: Yes this is a relativity problem, and there are different ways to explain it. Potential energy has mass (that which you can measure on scales and balances) but not rest mass. One way to see it, is to slow down all reaction products (converting their kinetic energy to heat) and then measure the rest mass of the products. It is now usual in relativity to call what used to be rest mass as just mass.  Energy (kinetic or potential) is not mass, even though scales and balances will measure it. Gah4 (talk) 09:48, 5 September 2017 (UTC)
thread_title:  Efficiency?  

message: Fusion could take place at much lower temperatures due to Tunneling effect
--Hlfhjwlrdglsp (talk) 20:51, 11 September 2010 (UTC)
replies: text: Compared to what? —Keenan Pepper 00:36, 12 September 2010 (UTC)
replies: text: To what is considered in current models on nuclear fusion.--79.116.77.56 (talk) 20:55, 15 October 2010 (UTC)
replies: text: Current models include the effect of tunneling. Moreover, they are backstopped by actual measurements of rates, so the calculations are proven corrent.SBHarris 01:22, 16 October 2010 (UTC)
replies: text: What is the actual nuclear-nuclear distance for the condensed matter inside the Sun? I've never seen any "Current Models" take that into account for tunneling contribution; every model I've seen is based on free space interaction of nuclei that have been studied in beam accelerators. I really doubt that there is any significant mean free path inside Stars. Shjacks45 (talk) 17:56, 25 August 2011 (UTC)
thread_title:  Tunneling effect 

message: Why "fussion" (with two "s") redirects here? I'm not a native speaker of english and wasn't sure of the correct spelling, tried with two "s" and was redirected to this page. But the spelling "fussion" doesn't appear even once in the entire article. It's a correct spelling? 188.86.65.35 (talk) 12:57, 11 November 2010 (UTC)
replies: text: Incorrect spelling, a common mistake. Binksternet (talk) 14:41, 11 November 2010 (UTC)
replies: text: Indeed, fusion is the correst spelling. It doesn't help that u and i are next to each other on most if not all keyboards, and the opposite process to nuclear fusion is nuclear fission. 62.252.178.158 (talk) 12:23, 20 February 2011 (UTC)
replies: text: There's a Mackie loudspeaker product line called Fussion, but it does not merit an article—not so notable on its own. The redirect is properly aimed here. Binksternet (talk) 15:58, 20 February 2011 (UTC)
thread_title: Why "Fussion" redirects here?

message: After reading through the page on nuclear fusion, i was really impressed by the quality and detail shown and thus i recommend that the article receive a featured article stamp.
I don't. Too many mistakes. Also, the caption for the diagram on the left mahes no sense.  — Preceding unsigned comment added by 184.147.123.113 (talk) 22:04, 30 December 2012 (UTC)
thread_title:  Quality 

message: The link to The FusionWiki has been reverted a couple of times, but seems legitimate and valuable.  The Laboratorio Nacional de Fusión that hosts it has been around for decades, and the Wiki is a couple of years old.  The list of articles is extensive, and many seem substantive, though technical.  It is largely in English.  Can we keep it unless there is consensus (and clear and specific evidence) that it is inappropriate?  Thanks, Wwheaton (talk) 17:18, 21 March 2011 (UTC)
thread_title:  Laboratorio Nacional de Fusión FusionWiki link 

message: 1. Several non-science people seem confused by the explanation at the beginning of this article, as illustrated by the picture included of D+He3. The term was coined to describe the macroscopic astrological phenomenon of the stepwise H+H+H+H=He or miraculous 4H=He. Reactions like 2H + 6Li = 2 4He  or  1H + 11B = 3 4He (in Aneutronic fusion) to the layman appear to be Fission reactions. 
2. The reference to Quantum tunneling should reference Muon-catalyzed fusion or include references of its own. One concept in tunneling that is not realistically described in this article (and would be apparent if contributors read references) is that tunneling probability has a time variable. This is truly catalysis because the Muons induce several hundred fusions before being expended (decay). The contact time as described by the thermal temperature, hence the speed of even low temp particles, in Plasma is around 6 orders of magnitude shorter than Muon induction. This makes it extremely unlikely that "quantum tunneling" is responsible for the low energy plasma reactions. As Deuterium Molecules greatly outnumber Helium atoms produced it would be unlikely for Muon to find one; and the 4-14 MeV (product 3H or  3He or 4He) energy of reaction effectively separates the Muon for the next reaction. See http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/25/048/25048388.pdf.  Shjacks45 (talk) 05:33, 7 August 2011 (UTC)
replies: text: As I recently noted above:  Fission is related to the liquid drop model, and the balance of electrostatic and nuclear forces. That occurs in heavier nuclei. Fusion is mostly related to the especially stable alpha particle (He4 nucleus), and so is the reason the B11 reaction is a fusion reaction. Gah4 (talk) 22:34, 1 March 2019 (UTC)
thread_title:  Con-fusion 

message: The models described are from particle beam reactions in accelerators. Or low density high temperature plasma experiments. Under Neutron source (Neutron generator) the fusion reactions that generate neutrons are from nuclei accelerated to as little as 5,000 volts.
Solar fusion conditions are quite different. The condensed matter (tons per CC) inside the Sun has a internuclear distance and short free path that favors tunneling. As atoms have been broken down the electrons in Solar plasma are closer than atomic orbital electrons. Although endothermic in 10E7 temperature environment, electron capture by a proton to form a neutron, or electron capture by the two proton 2He seems feasible. Gammas at solar temperatures can spontaneously form electron-positron pairs. Need to consider Deuterium "decay" due to solar thermal environment exceeds binding energy. Helium burning is discounted however Tritium and 3He "burn" at Hydrogen fusion temps. (Biggest problem of fusion is excess energy causes fission of products; intra-Solar conditions favors endothermic reactions e.g. proton-proton fusion with emission of positron to remove excess energy?)
The Deuterium reactions show a drop off above 1.5 MeV; Deuterium binding energy is 2.2 MeV, splitting of Deuterium by Gammas is used in Neutron sources. Tritium fissions at lower energy.
Shjacks45 (talk) 05:23, 26 August 2011 (UTC)
thread_title:  Unrealistic Fusion Model 

message: Re: "This is due to a greater disintegration rate for 62Ni in the interior of stars driven by photon absorption." Any chance that Proton absorption is the real culprit? ϢereSpielChequers 18:55, 31 August 2011 (UTC)
thread_title: photon absorption

message: As of Sept 25, 2012 NIF is certain to miss its Sept 30 deadline to achieve break-even.  By law the facility has 60 days to prepare a report on the remaining barriers and way forward.  The likely outcome (Science 9/21/2012 pg 1444) is that confinement by indirect laser inertial confinement will be abandoned as an approach to fusion energy.  The NIF will continue to be used to model fusion in support of the US nuclear weapons stockpile.  To date model calculations have failed to predict the observed physics.  — Preceding unsigned comment added by 216.96.79.86 (talk) 17:50, 28 September 2012 (UTC)
thread_title:  National Ignition Facility 

message: I have just been lookng at the Encyclopaedic Dictionary of Astrophysics, by S.K. Basu on Google Books. It appears that much of this Wikipedia article is a straight plagiarism/copy-and-paste from this book. 
For example, if you read from "Important Reactions" on page 264 of Basu's book, you will see that it is word-for-word identical to the "Important Reactions" section on this Wikipedia page.
Could somebody please inform me what the Wikipedia policy on this is? The entire text is not available on Google Books so I am assuming that the work is still in copyright and that the plagiarism on this site may well be illegal.  — Preceding unsigned comment added by 92.237.144.193 (talk) 18:45, 24 December 2012 (UTC)
replies: text: It appears that the book may have copied Wikipedia.  This version of the article from 2006 predates the 2007 copyright date of the book.  I would also ask if content from Wikipedia may be used in a copyrighted text; I believe our license allows unlimited re-use.  This may still require further inspection.  Wikipedia talk:Copyright problems appears to be active enough to solicit for opinion. Tiderolls 19:10, 24 December 2012 (UTC)
thread_title:  plagiarism 

message: This needs the cross sections for more reactions.  This includes those listed, but also other reactions.  Does anyone know the details around the reactions that generate helium?  — Preceding unsigned comment added by 69.205.70.3 (talk) 00:11, 17 January 2014 (UTC)
thread_title:  reaction cross sections 

message: Looks like that researchers managed to generated more energy than put into it using a beam-target fusion.  --PLNR (talk) 13:39, 13 February 2014 (UTC)
thread_title:  Nuclear fusion hits energy milestone 

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message: I'm thinking here about the bonding between positive nuclei. Obviously protons/nuclei overcome the electrostatic force and come into proximity, at which point fusion may occur due to the strong interaction. But exactly how this happens is represented differently in some lay sources, and I'd like to check we get it right.
Some sources represent this process of being able to overcome electromagnetic forces as being mediated by random quantum tunneling. Other sources state it's an effect of sufficient kinetic energy. While fusion itself is primarily an effect of the strong interaction, it's not entirely clear whether some fusion processes also involve effects due to the weak interaction as well (eg if a non-nucleon particle is ejected during the fusion such as an electron/positron/neutrino).
Are we being sufficiently clear (especially in the introduction which is simpler text) which interactions/effects permit fusion / are involved in it? FT2 (Talk | email) 06:31, 5 September 2017 (UTC)
thread_title:  Are we correctly representing the basic roles of the strong interaction, tunneling effects, and KE? 

message: I just wanted to thank the authors of the section on which fusion reactions are plausible candidates for a source of sustainable fusion power. That's the question that interests me, and your answer is clear, well-organized, precise, and comprehensive. Keep up the good work!
Invisible Flying Mangoes (talk) 02:35, 12 September 2017 (UTC)
thread_title: Great work on the list of plausibly exothermic terrestrial fusion reactions

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thread_title:  External links modified 

message: The graph at upper right is mislabeled and incorrectly described.  It is not a graph of binding energy; in reality, binding energy continues to increase going to the right of Fe-56 as the number of nucleons increases.  The correct y axis label "Average Binding Energy per Nucleon", is an important distinction.  Recommend using the terms and description used for the same graph located in the Wikipedia article entitled "Iron Peak".
The graph helps to explain, using a single curve, how fission and fusion are possible.  The y maximum at Fe-56 implies that Fe-56, with a relatively high average binding energy per nucleon, is held together tighter than nuclides on either side of Fe-56, where the average binding energy per nucleon decreases in either direction.  Energy is released, both when lighter nuclides fuse to form something heavier, and when heavier nuclides fission to form lighter ones.  In addition, energy must be added to initiate the reaction in either case, except when certain heavy nuclides fission spontaneously.
The current description in this article is nonsense: "The formation of nuclei with masses up to Iron-56 releases energy, while forming those that are heavier requires energy input. This is because the nuclei below Iron-56 have high binding energies, while the heavier ones have lower binding energies."  No.  That is not what this graph is saying at all.
Jthomason3 (talk) 02:15, 3 June 2018 (UTC)
replies: text: I suspect that this is the usual case of everyone knows it, and so doesn't bother to say it. How much longer is the article if you add per nucleon to each one?  How about if you say at the top that binding energies are always per nucleon?  As for spontaneous fission, is it the usual quantum tunneling?  I haven't thought about that for a while. Gah4 (talk) 03:09, 3 June 2018 (UTC)
thread_title:  "Nuclear Binding Energy Curve" Mislabeled 

message: Is it appropriate to mention Greenhouse Item in the opening?
It seems to me we should be discussing self-sustaining fusion there, and Greenhouse Item wasn't. It was the fusion of a few grams of D-T driven by several kilograms of fissile material, not self-sustaining fusion. Boosting isn't used to provide extra energy to a nuclear weapon, it's used to provide additional neutrons. I'm not sure it's appropriate to include it. Staged thermonuclear weapons? Sure, mention it because the secondary stages clearly output more energy than goes into them, but I'm not so sure about boosted weapons. Kylesenior (talk) 07:15, 28 May 2020 (UTC)
thread_title:  Greenhouse Item 

message: Why is the mention of the neutrinos produced almost entirely missing (except in the CNO cycle section) and neutrinos are missing from all reaction equations? --vuo (talk) 11:32, 3 August 2020 (UTC)
thread_title:  Neutrinos?? 

message: This article seems to be duplicated by thermonuclear fusion, which should I think be merged into this one.
They seem to be exactly the same topic, and this article name is the more concise. 
Discuss here I think. I have placed a heads-up at Talk:Thermonuclear fusion#Possible merge and redirect. Andrewa (talk) 13:37, 1 May 2021 (UTC)
replies: text: i think that they should not as in the future they might have a breakthrough in technology might sepreate them both 82.113.249.177 (talk) 17:42, 26 January 2023 (UTC)

text: I agree with your point, but only if thermonuclear fusion becomes its own subsection, with other content that has already been mentioned in nuclear fusion being placed to appropriate sections. Nuclear fusion does not only figurate thermonuclear fusion, and other types of fusion, such as pycnonuclear, should be distinguished too (and merged too). The article also seems to disregard the various different types that authors have incorporated in their calculations of nuclear fusion rates - [1], [2] (thermonuclear w/ weak and strong screening, thermopycnonuclear, pycnonuclear), as examples, which further supports my point that distinction is still required. Mk0uQ (talk) 18:24, 9 August 2022 (UTC)

text: Klbrain (talk) 11:28, 2 April 2023 (UTC)
thread_title:  Possible merge and redirect 

message: This infamous falacy is at work in the following 2 sentences:
"At the temperatures and densities in stellar cores, the rates of fusion reactions are notoriously slow. For example, at solar core temperature (T ≈ 15 MK) and density (160 g/cm3), the energy release rate is only 276 μW/cm3—about a quarter of the volumetric rate at which a resting human body generates heat."
The number 276 μW/cm^3 results from dividing the total solar power output (~4*10^26 W) by the total volume of the sun (~4/3π*696,000,000 m^3) and is fairly irrelevant, yet fun to know. But in this case the message is really quite wrong because a point is made regarding the energy release rate at core-temperature (15 MK) and -density (150 t/m^3). So the total energy certainly needs to be divided by the volume in which fusion occurs at all, i.e. the core. Taking the number of 24% of the solar radius, found with a quick search on Wikipedia itself, one arrives at \frac{3.8*10^{26}W}{4/3\pi \cdot0.24\cdot696,000,000m^3}\approx19.4mW/cm^3(=19.4kW/m^3in SI units) which is about 70x the number currently stated.
Can I correct this number? This is obviously original research and I don't have a source for it, but since it is so simple to verify, is a source really necessary?
--Felix Tritschler (talk) 12:37, 8 March 2022 (UTC)
thread_title:  The "Human body produces more heat than the sun"-falacy 

message: Nuclear fusion#Requirements:
: The reaction rate (fusions per volume per time) is ⟨σv⟩ times the product of the reactant number densities
Unit is given, in the diagram, as m³/s for the reaction rate. This does not add up. number density is mol/m³, σ (cross section, area) is m² and v is velocity is m/s. In total we get: mol/m³ * mol/m³ * m² * m/s = mol²/(m³*s). We have mol² left over to get to m³/s, missing somewhere, potentially in the cross section?
But it does not end here, this paper states:
: The volumetric reaction rate, that is, the number of reactions per unit time and per unit volume
Per time per volume, that would be 1/(s*m³) for the reaction rate. Not m³/s as per wiki. It makes more sense this way, since we want to multiply this by some reactive plasma volume and some amount of time to get the conversion. The formula given is (ignoring the integers, since they have no units):
: R = n*n*⟨σv⟩
As we already established, that adds up to mol²/(m³*s), with factors on the right missing the mole(s) (or they need to be included on the left).
1. We have some missing units
2. Reaction rate has a different unit, either mol²/(m³*s) or 1/(m³*s), but not m³/s
I come from the chemical side of things, I am not going to edit this without feedback on how Physicists handle units and what they think is missing. Eheran (talk) 13:17, 17 May 2023 (UTC)
thread_title:  Reaction rate - Units do not add up 

message: In the table in the section "Neutronicity, confinement requirement, and power density" under the D+D reaction, it states that 66% of the released energy goes into the neutrons. This is not correct. D+D has two branches, but each overall is 3D -> He-4 + p + n. Combining the two branches, the total energy in the neutrons is 38.1%. Reference: page 36 of Morse (2018), Nuclear fusion, Springer. https://link.springer.com/book/10.1007/978-3-319-98171-0 176.199.209.120 (talk) 09:17, 20 May 2024 (UTC)
thread_title:  Error in energy in neutrons in the D+D reaction