Talk:Nuclear fuel

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Past merge[edit]

Sorry DV8 2XL, I didn't bother to look at the history page until I had added several things to this article, so I didn't see that it has been merged with Nuclear fuel cycle in the past. It makes sense, since I actually stole a paragraph from that article to explain the common nuclear fuel types. As is, I think it is adequate to have this page focus on fuel forms as I've tried to do since I haven't yet found anything else this specific about fuel forms on wikipedia (unless I've just never looked in the right place). Hopefully I'll be able to find pictoral examples of each, but I wouldn't hold my breath. Lcolson 22:29, 14 December 2005 (UTC)

Reordering/formating[edit]

Nice work Cadmium, you added order to my chaotic additions. I didn't even think of adding MOX and UOX (some of the many improvements). Lcolson 01:52, 16 January 2006 (UTC)

Nice page[edit]

I have forgotten what ever it is I said about this page - but it looks good now. I've made a few additions to it and some wikilinks, and I'm going to write a section on the fuels used in atomic battery applications shortly. --DV8 2XL 19:55, 31 January 2006 (UTC)

Global Nuclear Energy Partnership[edit]

In February, 2006, a new U.S. initiative, the Global Nuclear Energy Partnership was announced - it would be an international effort to reprocess fuel in a manner making proliferation infeasible, while making nuclear power available to developing countries. Would someone like to blend GNEP into this article? Simesa 20:57, 9 February 2006 (UTC)

Fuels in pellet graphs?[edit]

Should not fuel be component or substance there? Midgley 03:47, 4 April 2006 (UTC)

Using PCBs as Energy[edit]

Is it possible to generate and capture energy in the process of cleaning up PCB waste? Can that 'energy' be stored and used to power businesses or homes?

PCBs are not nuclear fuel, but a chemical byproduct from various industrial practices, so this is not the correct place to post this... but I'll humor you.
If I remember my chemistry right, PCB's are poly-chlorinated biphenols. I think it is a benzene ring on them that causes the problem (not sure... its been close to a decade since I learned about them). You probably could burn them for energy, but if the burning process wasn't complete you would probably get some polutants going out the stack and poluting the air and poisening people, which is why no-one has probably tried doing this.Lcolson 20:50, 17 May 2006 (UTC)

Article Restructuring[edit]

I don't know about the rest of you, but PIE isn't the first thing I think of when I hear the words "nuclear fuels". Also, I think spent fuel should be placed moved, as well as some other stuff. I've never done much editting on here before, so anyone feel free to give me some criticism or reverse anything I do.Ajnosek 00:30, 23 June 2006 (UTC).

I disagree with your edit to the section on chernobyl, the nature of the fuel can prevent a core damage accident from becoming a serious accident. The events at three mile island show that core damage does not always lead to a nasty accident with off site effects on the level 6 or 7 scale.Cadmium 20:45, 23 June 2006 (UTC)
I didn't mean to change the meaning of what I was editting, but I can see how I did make that more vague now. There was a misplaced modifier. But that doesn't matter now since I see you yanked that whole section. I was thinking about doing that myself, because I don't know how relavent it is to this page, but instead I just moved it to the bottom. Thanks for the help. Ajnosek 22:58, 23 June 2006 (UTC)

So I just did a bunch of work on the TRISO fuel part, but I forgot to sign in before I did. Is this a big deal? Ajnosek 19:11, 14 July 2006 (UTC)

I also reworked alot of the fuel behavior section, but I couldn't get the graphs to organize nicely. Does anyone know how to resize and move them around so they look better? I am also thinking about removing PIE from that subtitle (but keep it in the section of course) just because it's a small part of the section. Also, I believe (although I may be wrong) that the words "atomic battery" generally refer to RTGs as well, so I restructured that part more consistent with how they do on the atomic battery page. Ajnosek 22:32, 22 January 2007 (UTC)

New photo[edit]

I do not see the utility of the new diagram in the article lead. Looking at what it was derived from, it looks like an attempt to make nuclear fuel appear in a bad light. The nuclear symbol has been added in several spots with a dull red tinge around it, and two mushroom clouds and shells were also added the original photo is here.

Nuclear Fuel Process

Now compare it to the new one.

Nuclear Fuel Process

The original image had none of these. Plus, I do not think that a specific diagram about a type of nuclear fuel cycle should be at the front of an article about nuclear fuel. I think the binding energy diuagram is much better as the lead diagram since it is much more general and fits with the article better. 69.129.195.170

I think that there should definitely be something like the diagrams at the right somewhere on this page (showing the full fuel cycle) but I agree that the new one is inadequate for a few reasons, among them: misspelling of "depleted", the inclusion of radiological symbols even for things which are weakly radioactive (i.e. DU). I'm less concerned with the shells and the clouds, though -- they are pretty standard symbols and it is fairly incontrovertible that the fuel cycle can be put to weapons purposes. I think the original one fails when it doesn't indicate that this has often been the result of certain ends of the fuel cycle. But I think the military/civilian uses should be differentiated, somehow. --Fastfission 04:23, 7 February 2007 (UTC)
I agree. A nuclear fuel diagram could compliment the article well, but the current one (the bottom picture) doesn't do it justice. The top one is much better, but could still use some work. Most of the spent fuel can be recycled, so that arrow should be larger and the waste smaller. Also, can't MOX fuel be reprocessed too? Maybe a simple arrow from "MOX fuel" to "power reactors" would be more appropriate than one going behind "power reactors". Also, is there liquid waste (other than low level waste)? Otherwise it is redundant. Ajnosek 05:03, 10 February 2007 (UTC)

This diagram is graphically beautiful but I think it is in some ways incorrect or at least misleading and therefore requires revising. The main problem is that although according to the title it describes the production and use of nuclear fuel, it nevertheless concentrates on military uses of nuclear technology. This should not be the case if the aim is to accurately describe fabrication and use of nuclear fuel.

Fact is that no nation is known to use nuclear power plant fuel in nuclear weapons production and therefore their inclusion, at least so prominently, is questionable if not outright biased. Interestingly nowadays the reduction of nuclear weapon stockpiles through the use of MOX fuel is by far more commonplace than the fabrication of new weapons materials. Nevertheless the arrow towards nuclear weapons is much larger and thicker than the one away from weapons stockpiles. This gives a completely biased picture of the matter since a theoretical, non-existent use of nuclear fuel is shown more prominently than actual, important uses.

Also the DU used in conventional munitions comes from military stockpiles and should not be included when describing the use of nuclear fuel. For some reasons the more relevant civilian uses of DU are not mentioned at all. One also wonders why, if miltary use of nuclear materials from non-power-plant reactors is mentioned, the beneficial use of similarly produced isotopes in medical purposes and fire alarms are not mentioned at all. These uses save thousands of lives every year and are thus very important uses of uranium derived materials.

Stamping a "radioactive" sign on everything also seems unnecessary, especially considering that DU, which has been given one, is less radioactive than natural uranium. Because of these reasons I think that Wikipedia should return to use the original graphics on this page. This is important for keeping the artcle unbiased and neutral. Tungsten 11:31, 1 March 2007 (UTC)

  • I think that the newer diagram covered with threatening looking radiation symbols and mushroom clouds/bullets is very POV. Think that we must use a NPOV diagram to show the nuclear fuel cycle, I dislike the current diagram in terms of style (I think it looks rather childlike and overcoloured) but it is better than the proposed replacement.
  • I think that we must avoid a doom and gloom diagram (such as one which greenpeace might supply) and also we should avoid using a 1950s style selling the joys of atomic power diagram which would have lots of happy looking nuclear workers (overjoyed at the prospect of making/using/reporcessing fuel). (I do not know if either of these diagrams exist but the stereotypes represent two equally wrong POV diagrams which might be used).Cadmium

Power densities[edit]

The diagrams show graphs for an alleged power density of 1000W per m^3 , claiming the oxide fuel is destroyed under such conditions. However, many oxide fueled reactors produce more than 500MW. Wouldn't this imply that these reactors would have to contain millions of tonnes of uranium? Where am I going wrong here? 90.149.55.128 (talk) 23:22, 4 January 2008 (UTC)

The graphs show several things. First, with a constant power generation, and assuming normal conditions (realistic heat transfer coefficients, radial fuel geometry, etc...), the maximum temperature of the fuel (i.e. in the center of the radial pellet) will increase as the radius of the pellet increases (from more volume heating, and a higher volume to surface area ratio which translates into less heat loss). Secondly, the graphs also show that for a constant pellet radius, the maximum temperature increases as the power density increases (kinda like turning a burner to a higher setting on an electric stove).Lcolson (talk) 23:45, 4 January 2008 (UTC)
Good catch 90.149.55.128. The numbers are probably per meter of length of the fuel rod, not cubic meters of fuel. I can't change it until I can verify this is the case. Paul Studier (talk) 23:54, 4 January 2008 (UTC)

I am sure that the maths is correct for the power density for the uranium fuels where the power is the heat generated per unit volume of the fuel material. I obtained the equation from a good nuclear chemistry text book which is a 4th edition so any silly errors should have be ironed out. I know that it is common for thermal power output to be expressed for a fuel pin in terms of W per meter of length but for this point I am sure that W per cubic meter is correct. I would sugest that if any one has any further worry that they should try dimensional anaylsis on the equation.Cadmium (talk) 15:31, 19 January 2008 (UTC)

I don't have your book. From [1] we find that used Candu fuel, after a year, gives off 100W/20kg or 5W/kg. A cubic meter of Candu fuel would probably weigh 10,000kg, so Candu fuel would give off 50,000W/m^3. This far exceeds the figures given for an active reactor. In addition, Candu fuel is not enriched so would be colder than LWR fuel. Paul Studier (talk) 19:16, 19 January 2008 (UTC)

Dear Paul,

The power density I selected was for fuel which was in use, and the power densty was for the UO2 (or what ever else such as UN or UC) is self rather than the whole fuel element (fuel + cladding and other hardware). This may have made by value rather higher looking than what you would expect for CANDU fuel. I took the idea of the graphs from a NASA document which was on the subject of small reactors for use in space. If I was designing a reactor for use in space I would try to increase the power density as far as possible, I can not recall the "normal" power density for a reactor such as a PWR or BWR in terms of kW(t) per cubic meter of uranium dioxide in the fuel. If you have the value per meter of a "fuel rod" and you know the pellet diamter and the number of pins which make up the "fuel rod" then I am sure that you could estimate the power density per cubic meter of the actinide fuel.

When I did the graphs I took a typical pellet diameter, and by mistake I doubled it. After I had made the graphs I looked at them and they mad such a good job of explaining the difference in T between the rim and the core of the pellet I never made the effort to correct them. What I was aiming to do was to get over the following points.

1. The core is hotter than the rim. 2. If the diamter increases the difference between the rin and the core becomes greater 3. If the power density is increased then the effect becomes stronger.

In real life one should be aware that the rate of fission in the rim is more then the core of a pellet, this is becuase the thermal neutron flux at the edge of a pellet is higher than the core. As a result the rim can have a much higher burnup then the core. I have not tried to correct for this effect in the graphs, to be blunt it would be a nightmare as the maths would be very hard.

If I was you and you do not have the book, I would try Dimensional analysis as a method of checking the equation. I have a great love of dimensional analysis and I think that it is the nearest thing that physics has to a cure all.Cadmium (talk) 20:19, 20 January 2008 (UTC)

I think you're missing the point to be honest. It seems like the units are wrong. A few hundred W per cubic meter would imply that the core of a large 1500MW reactor would be much larger than the quoted sizes in most designs. Think about it 1500 MW = 1500 000 000 W , so if the fuel's power density is only a few hudnred W , then the reactor would have to be several million cubic meters large, making it hundreds of meters each way. Obviously real power plants are not that large so the power density in the fuel must be much larger. Is it possible you got the units wrong ? I.e W rather than kW ? 85.224.219.135 (talk) 18:18, 21 January 2008 (UTC)

First, in the equation, ρ is clearly the volume power density, like it says. (Does anybody need a derivation?) Second, the maximum temperature difference scales with the linear power density, ρ rpellet2. Since the maximum temperature increases in the series of the first three diagrams, clearly the volume power density is being held constant, as it says, and not the linear power density. The remaining question is whether W m-3 are the proper units. Uranium metal has a thermal conductivity of 27.5 W·m−1·K−1, the temperature difference for metal in the last picture is about 700 degrees, with a rim radius of 0.01 m. That works out to 770 MW/m³ ( = 700 K * 4 * 27.5 W/m/K / (0.01)² ), close enough to 1000, but the units must be MW instead of W. This also seems roughly consistent with the above arguments about the size of reactor cores. I'll make the change. --Art Carlson (talk) 11:10, 12 March 2008 (UTC)

I think those graphs are hard to make heads or tails of, and they are horribly done. Maybe we should just delete them. Ajnosek (talk) 02:10, 20 May 2008 (UTC)

It also sounds as if there's a tad of original research involved in the graphs. And one of the points to be delivered "The core is hotter than the rim." is apparently based upon the supposed design being considered; has a nuclear engineer stated that? The designers of reactors would know such characteristics and whether those are desirable; if not desirable the design of actual reactors might reduce the undesired heat (there are three obvious changes, one of which would not be apparent in the location of fuel rods or other reactor diagrams). -- SEWilco (talk) 04:43, 20 May 2008 (UTC)

Lightest possible reactor fuel?[edit]

What is the lightest possible reactor fuel - is there anything below thorium? Particularly, is it possible to develop a mixture of comparatively light metals (well above Fe, of course) that are fissionable or can produce fissionable products, which once irradiated by an external source, produce short-lived radioactive products that continue to produce the radiation to catalyze further transmutation and fission steps? If it is possible, does such an approach offer a way to avoid production of long-lived nuclear waste? Wnt (talk) 16:30, 30 June 2008 (UTC)

See https://en.wikipedia.org/wiki/File:Chart_of_Nuclides_-_Thermal_neutron_fission_cross_sections.png. In short, no.50.147.26.108 (talk) 19:09, 17 April 2014 (UTC)

Unwanted neutrons?[edit]

The section on second generation nuclear fuels says "Neutrons are an unwanted byproduct of fusion reactions in an energy generation context, because they are absorbed by the walls of a fusion chamber, making them radioactive." This is partially true, but for reactors using first generation fuels neutrons are an essential product, since they are used to generate tritium from Li-6 in blankets around the fusion chamber. I would think that the neutron economy of the D-T fuel cycle would require close to a one-to-one conversion of neutrons to tritium. NPguy (talk) 18:11, 30 January 2010 (UTC)

Fuel "assembly" or "bundle"?[edit]

Which should we use? We should be consistent. Ajnosek (talk) 19:55, 21 July 2010 (UTC)

- I vote for assembly. Until someone points out a good reason to pick one over the other, I think It's somewhat arbitrary. I just think assembly sounds more technical. Lcolson (talk) 22:56, 23 July 2010 (UTC)

Use either, as appropriate. A fuel assembly for a CANDU reactor is known as a fuel bundle. NPguy (talk) 17:06, 24 July 2010 (UTC)

Fuel Load[edit]

Hi all. Roughly what is the full load (kg) of fuel per reactor type? I can't find any information anywhere. Any info appreciated. Captain deathbeard (talk) 10:04, 22 October 2010 (UTC)

Separate Fission from Fusion[edit]

This article tries to discuss Fissile and Fusionable fuels together. I don't see much logic in this - although they're both 'nuclear' thay have little else in common.

I think it should be split - probably into three - a very short intro as 'Nuclear Fuel' then separate articles for 'Nuclear Fusion Reactor Fuels' and 'Nuclear Fission Reactor Fuels'

Any Thoughts ? —Preceding unsigned comment added by 207.245.198.135 (talk) 10:34, 17 January 2011 (UTC)

I think the two are already separated fairly cleanly and clearly. They are both referred to in the intro; the bulk of the discussion is on fission fuels, but there is a short section on fusion fuels at the end. NPguy (talk) 01:22, 18 January 2011 (UTC)

Thorium ?[edit]

In the intro, thorium isn't mentioned at all (although this material seems to become quite popular nowadays due to people as Kirk Sorenson. Also, thorium is only briefly discussed furtherup, but only using 1 type of reactor (molten salt reactor which uses a composite fuel, rather than just plain thorium). I'm not sure whether thorium can be used at all on itself, but I assume so, and their do seam to be different reactors types using thorium, ie SSTAR.

Finally, also mention that existing uranium reactors can be converted to run on thorium. 91.182.214.13 (talk) 13:43, 28 April 2011 (UTC)

  • I have heard/read that some countries such as USA, India, Russia, and China have investigated using thorium for their fuel cycles in the past, but the neutron economy just couldn't make it work in thermal neutron systems. The literature is littered with failed attempts at making thorium work in standard thermal fuel cycles. From what I understand, it has only had a reasonable chance in liquid systems (epithermal? not quite fast but faster than thermal?). Maybe I'm wrong as to the reasons thorium failed, but I seem to recall that this is what I'd found in the past from a survey of the empirical data out there.Lcolson (talk) 05:21, 29 April 2011 (UTC)
Thorium cannot run on it's own, as it's not fissile; it is fertile. You need a fuel to help thorium start making U-233. One concept is, once you have enough U-233 to remain critical, you can keep feeding the reactor more thorium to breed more fuel. I know there are difficulties implementing this, but I do not know what they are, and I speculate that most thorium reactor designs would probably use a mix of fuels to sustain the reaction. Ajnosek (talk) 04:24, 19 July 2011 (UTC)


Greetings, I am willing to help anyone edit this page to provide a bit more information on thorium, which is the fuel of choice for India (and probably China as well.) I will add a request on the Thorium page. Joel J. Rane (talk) 18:03, 8 March 2012 (UTC)
Here thorium is only mention a few times and a section on the thorium fuel cycle might be appropriate here.--Stone (talk) 19:41, 8 March 2012 (UTC)
This article does need a section on thorium fuel, but this need be no more than a summary of the main article on the thorium fuel cycle. NPguy (talk) 03:47, 10 March 2012 (UTC)

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Electro-Magnetic Field from nuclear fuel[edit]

I acknowledge that the basic fundamental of nuclear fuel is that it gives off heat, which is used to create steam to power turbines. But does nuclear fuel give off an electro-magnetic field? If yes, why create steam? Why not just use the electromagnetic field to power a motor? If no electro-magnetic field is created, then no further questions. Marc S. Dania Fl. 74.166.156.250 (talk) 01:18, 11 April 2012 (UTC)

anybody want to answer this???? marc s. 74.166.156.250 (talk) 21:00, 11 April 2012 (UTC)

new fuel rods vs spent fuel rods[edit]

I've heard (alas, not from a WP:RELIABLE source) that "New fuel rods are only very slightly radioactive, and are safe to handle without shielding."

This seems counter-intuitive, since other fuels -- petrol, natural gas, gunpowder, etc. -- are generally considered far more dangerous when new. After then energy has been extracted, the end product of such fuels -- carbon dioxide, water, etc. -- is generally inert and relatively harmless.

Can we add information to this article to either confirm or deny the above quote? Does the radioactivity of a fuel rod monotonically increase as it is being used, or monotonically decrease, or is there some more complicated behavior? --DavidCary (talk) 15:02, 11 April 2012 (UTC)

If this new fuel rod is only enriched uranium and no MOX fuel element, than it is radioactive similar to natural uranium in a hermetic metal tube. A fuel rod like that I would not consider a real danger if I do not have stay next to it for a few hours.--Stone (talk) 21:40, 11 April 2012 (UTC)
Does nuclear fuel give off an electro-magnetic charge? is it feasible for nuclear fuel to supply electric current instead of heat for steam power? Marc S. Dania Fl 74.166.156.250 (talk) 21:02, 14 April 2012 (UTC)

The radioactivity of a fuel element increases monotonically during burnup as fission products accumulate and supporting structures are activated by the neutron fluence. I don't think that any feasible reactor could reach equilibrium for this process?? Wikipedia already has images of technicians handling fresh nuclear fuel assemblies with little protective equipment, and exposure rates from new spent fuel can be >10^5 R/hr near the assembly. This exposure rate is sufficiently high that even running past the bundle would result in significant radiation sickness, with an LD50 accumulated in a few seconds. 50.147.26.108 (talk) 18:23, 17 April 2014 (UTC)