Talk:Nuclear reprocessing

From Wikipedia, the free encyclopedia

WikiProject Physics This article is within the scope of WikiProject Physics, which collaborates on articles related to physics.
??? This article has not yet received a rating on the assessment scale. [FAQ]
??? This article has not yet received an importance rating within physics.

Help with this template Please rate this article, and then leave comments to explain the ratings and/or to identify its strengths and weaknesses.

Contents

[edit] Revert

I reverted 169.253.4.21's deletion because I believe the sentence to be correct and he/she gave no reason for the delete. I left a message on his/her Talk page. Simesa 18:07, 27 September 2005 (UTC)

[edit] Merging Nuclear reprocessing with Nuclear fuel cycle

I generally am not in favor of merging the two. If anything, the reprocessing article should be expanded. Here in the US, of course, reprocessing is a non-issue. Simesa 18:37, 30 September 2005 (UTC)

If the article is expanded, I'd say it should remain as it's own article. The reason why I proposed a merge is because the article in its current form is short enough to be a section in the larger Nuclear_fuel_cycle article. In fact, that article already has a section on nuclear reprocessing that pretty much says the same thing as this article (minus a few details). Solarusdude 19:00, 30 September 2005 (UTC)
    • I have expanded the article and will be adding more detail shortly. I have removed the redirect flag. DV8 2XL 08:36, 8 October 2005 (UTC)

[edit] 86.2.102.238

You are doing some good work here. Have you considered getting an account? We could do with some good editors like you. DV8 2XL 15:45, 23 October 2005 (UTC)

[edit] Reprocessing in the U.S.

Actually, the U.S. will have a functioning MOX fuel fabrication facility in the next few years. A consortium called Duke Cogema Stone & Webster (DCS) was awarded a contract from the DOE in 1999, so the project has been underway since 1999. Site preparation at the Savannah River Site (South Carolina) began in October. See www.dcsmox.com for more information. Talula 15:20, 16 November 2005 (UTC)

Thanks, I've made the addition. DV8 2XL 18:08, 16 November 2005 (UTC)
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 20:46, 9 February 2006 (UTC)
Done as per request. --DV8 2XL 20:54, 9 February 2006 (UTC)

[edit] Old processes

I have added a few sections on processes which have been replaced.Cadmium 20:51, 7 January 2006 (UTC)

[edit] Weapons grade

This process can be used to recover weapon-grade materials from spent nuclear reactor fuel, and as such, its component chemicals are monitored. - The first statement is not in general true. The process (like any chemical reprocessing) can't alter the isotopic balance of the uranium or plutonium. So there would be few if any cases in which spent reactor fuel could provide weapons grade materials simply by reprocessing.

When Magnox reactors are used to produce weapons grade plutonium, the fuel elements each spend only a few days (or sometimes hours for very high grades) in the reactor. What is reprocessed is hardly spent fuel. The longer the fuel spends in the reactor, the more of the Pu-239 captures more neutrons and becomes Pu-240, Pu-241 and Pu-242, all of them undesirable for weapons and unremovable. That's why online refueling capability is always used for weapons grade plutonium production, and why PWRs and BWRs can't be used to make bombs. Carter's famous non-weapons grade test was British plute from a Magnox, the actual isotope ration has never been released. Andrewa 06:32, 10 January 2006 (UTC)

What you say about spent vs irradiated fuel is technically true however the issue is somewhat moot since an opperator could remove fuel from a reactor at any time and use this reproccesing technology to recover weapon grade material.
Its not a moot point in most reactors, as a refueling outage takes many days and the loss of 1000MWe plus from a countries grid every 14 to 30 days tends to be noticed. Also both India and Pakistan had operational CANDU reactors (which has an online fueling capcity) when they started their weapons programs. But both choose not to employ them in this task, doesn’t that give a very strong hint that there are much easier ways to get bomb grade material than spent reactor fuel.
FYI - There are chemical processes that exploit the very slight difference in an isotopes propensity to change valency in oxidation/reduction, relitive to their sisters utilising immiscible aqueous and organic phases.
Those are enrichment processes and mainly developed to separate U-235 from U-238. To my knowledge similar processes do not exist to separate Pu-239 from Pu-240, and regardless it would be much easier to use low-burnup thermal reactors that don't produce large amounts of Pu-240 in the first place. Reactor grade plutonium isn't really much of a proliferation concern since any nation technologically advanced enough to produce reactor grade plutonium for weapons would without doubt be able to produce weapons grade Pu-239, which is significantly easier to make a weapons from. As mentioned above, the main proliferation risk with PUREX is if it is used in conjunction with reactors capable of refuelling on-load. Also, please add four ~ characters to the end of your contributions at the talk page, as that will automatically append the date you posted, which makes it easier to determine what discussions are still active. 137.205.192.27 17:17, 12 September 2006 (UTC)

[edit] Missing a Reprocessing Plant

I'm going to have an article for the reprocessing plant in Rokkasho, Aomori soon. It's not fully operational yet, but we need to include it and comparisons to the French plant. You can check back later, after I've finished that article and it should be easier. -Theanphibian (talk • contribs) 17:32, 14 July 2007 (UTC)

[edit] Inconsistency between article and source

"... though it still takes over a thousand years for the level of radioactivity to approach that of natural uranium [19]." Yet the link provided says: "The radioactivity of high level wastes decays to the level of an equivalent amount of original mined uranium ore in between 1000 and 10,000 years." Natural uranium and uranium ore are NOT the same. Uranium ore is the uranium as it comes out of the ground, and contains quite a bit of other elements. Natural uranium refers to ore that has been processed into pure uranium, but has the same isotopic breakdown as found in nature. The two are not interchangeable, as they are not the same. I suggest replacing "natural uranium" in the quoted section of the article with "uranium ore", or finding a source for the time required to decay to the level of radioactivity of natural uranium.192.235.29.95 13:18, 30 October 2007 (UTC)

[edit] Reprocessing vs. Recycling

What is the difference between "Nuclear Reprocessing" and "Nuclear Recycling"? Nuclear Recycling redirects to this article. They seem to be used interchangeably in articles like this one: Dr. Frank Settle. Nuclear Chemistry - Recycling Spent Reactor Fuel (English). Retrieved on 2008-04-17. and Tony Batt Stephens (2008-01-18). Porter looks at recycling nuclear fuel (English). Las Vegas Review-Journal. Retrieved on 2008-04-17. If they are indeed the same and recycling is just a reframe of reprocessing (like death tax is a reframe of estate tax or inheritance tax), then this should be clarified in the article.Kgrr (talk) 13:30, 17 April 2008 (UTC)

There are two answers to this question. One is that "recycling" is a public relations euphemism for reprocessing. People think "reprocessing" is bad but "recycling" sounds good. The other is that recycling involves the complete process of separating fissionable material from spent fuel, fabricating it into new fuel, and using it again in a reactor. Reprocessing by itself is not recycling - it's just the first step. NPguy (talk) 02:13, 18 April 2008 (UTC)
Also the vast majority output of reprocessing, a form of depleted uranium, is not recycled at all. It has some radioactive issues (U-232 mainly) compared to enrichment uranium tails, which needs shielding from if further processed, so generally has to be disposed of somehow. Also the U-236 content is a neutron absorber, so to reuese as fuel it needs extra enrichment. The UK has 27,000+ tonnes of it sitting around on storage sites in drums, awaiting a long delayed decision on what to do with it.[1][2] To be fair some of this reprocessed uranium, depending on burn-up, still has higher U-235 % than natural uranium, so could in principle be cheaper to re-enrich if enrichment and fuel fabrication plants were built with the U-232 etc problem in mind. Rwendland (talk) 13:33, 18 April 2008 (UTC)
Yes, there is a Reprocessed uranium article. --JWB (talk) 18:45, 18 April 2008 (UTC)
NPguy, You've provided two somewhat conflicting answers. Nuclear recycling redirects to this article. However, nothing in this article deals with the term recycling. If recycling indeed means "reprocessing" + "conversion"+ "fuel fabrication" then the article should say so. On the other hand, if recycling is merely a reframe (eupjhomism, or made to sound more politically correct...) of reprocessing, then this article should also explain that. Can you please provide a reference that will clarify this? I need to resolve this same issue in the Peak uranium article.
Rwendland and JWB, reprocessing is full of problems where the fuel gets ore and more "poisoned" by the transuranic isotopes. I think this issue seriously limits the number of times fuel can be reprocessed. I also don't understand if you can re-enrich reprocessed uranium. Won't the other isotopes of Uranium end up "poisoning" your enrichment facility? Kgrr (talk) 21:21, 18 April 2008 (UTC)
Not sure what you mean by poisoned by transuranic isotopes, or which product of reprocessing is getting poisoned. It is true that plutonium accumulates more even-mass isotopes as it is used in a thermal reactor and that these isotopes are less fissile; however both these and minor actinides are burnable in fast reactors, which can also breed more fuel from U-238 or Thorium-232.
Yes, you can reenrich reprocessed uranium, and yes, the enrichment equipment would become more radioactive from U-232, so it would likely be done in a separate facility from enrichment of fresh uranium. But keep in mind the stockpile of depleted uranium is far in excess of the amount of used uranium, so if the goal is simply U-238 for breeder reactors, it is easier to just use depleted uranium than reprocessed uranium.
If the goal is extracting U-235 from reprocessed uranium, and you really need to get rid of the U-236 and other less desirable isotopes, one option is enriching to nearly pure U-235, then downblending with U-238. This would take somewhat more energy than regular enrichment of fresh uranium, but probably less than twice as much, and anyway centrifuging uses far less energy than was used in gaseous diffusion enrichment plants. And, keep in mind the amount of U-235 in used uranium is only a third or so of the amount in the original fuel, and an even smaller fraction of the U-235 in the original fresh uranium before enrichment.
Regarding Peak uranium, it seems to me that much of the content duplicates existing articles, while the "peak uranium" idea itself is not very credible or notable. --JWB (talk) 21:57, 18 April 2008 (UTC)

I don't think there is any standard definition for nuclear recycling. I have heard it used both ways. The Department or Energy's fact sheet on recycling "Why recycle used nuclear fuel?" uses the term to mean separation, fabrication and reuse. On the other hand, its glossary defines recycling solely in terms of separation.

As far as how many times you can recycle, that depends in part on the type of reactor. Repeated recycling in a thermal neutron reactor builds up the heavier plutonium and other transuranic isotopes. In principle, it may be possible to recycle spent fuel indefinitely, but the buildup of non-fissile isotopes (those that do not undergo fission in a thermal neutron spectrum and may act as neutron poisons) requires an increasing concentration of plutonium to maintain reactivity in fuel. In a fast neutron reactor, most transuranics are fissionable and the higher isotopes therefore do not build up indefinitely.

Another result of recycling reprocessed uranium is the buildup of highly radioactive Pu-238. Neutron absorption by U-236 produces Np-237 and then Pu-238. This complicates further recycling of the plutonium from the spent fuel. NPguy (talk) 01:40, 19 April 2008 (UTC)

[edit] More Citations?

This article has a few citations, however, at least half of it has a alot of highly technical stuff which MUST have citations. Just a note. ~~PandaSaver —Preceding unsigned comment added by PandaSaver (talk • contribs) 01:50, 30 April 2008 (UTC)