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Post by anonposter on May 18, 2012 8:48:07 GMT 9.5
Yet no one even tried to see if just how reliable or unreliable it would be. That alone is pretty telling.
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Post by Janne M. Korhonen on May 18, 2012 16:41:39 GMT 9.5
Yet no one even tried to see if just how reliable or unreliable it would be. That alone is pretty telling. That may be so, but we don't really know. It does seem likely that the published tests that may have used below weapons grade Pu (the 1962 U.S. test and 1953 British "Totem" tests) did not use what we would call reactor-grade Pu. (In fact, a 1994 analysis of Totem fallout's Pu/Am ratios suggested the shots used WGPu, and the Brits later acknowledged that fuel-grade Pu was planned but was not available at the time.) But full-scale nuclear tests are not the only way to find out. What we know is that something freaked out the U.S. government sufficiently in the late 1970s that they technically speaking broke their own laws and the NPT treaty and sent weapons scientists to give classified presentations in countries operating or planning nuclear power. As far as I know, the essence of these presentations was that any Pu can be used in nuclear weapons, and that separated Pu should be guarded as diligently as nuclear weapons. I don't believe this was due to machinations of fossil fuel industry. Yet as I stated, I don't believe spent fuel is a major proliferation concern either, especially now when centrifuges make uranium enrichment so much easier than it was in the 1970s. But I do think the majority opinion among those informed with the subject definitely precludes statements such as "reactor-grade Pu cannot be used in bombs." |
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Post by davidm on Jul 10, 2012 5:37:58 GMT 9.5
The French in the past have been the big nuclear power folks and they have the experience with the Superphenix breeder reactor. So with all its history and experience why aren't they leading the charge on this source of "safe" energy that is self-perpetuating and so falling-off-the-log the obvious solution to our energy problems? This fairly recent paper on the Superphenix may give us some clue into the matter. MODERATOR
The paper referred to is an essay by a student in a Stanford Physics 241 Course and not a peer review paper.
Please supply a link to the quote you gave and re-submit. As per the Citation Policy please do not cut and paste large
slabs of text without your own analysis. |
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Post by grlcowan on Jul 10, 2012 6:08:22 GMT 9.5
... It does seem likely that the published tests that may have used below weapons grade Pu (the 1962 U.S. test and 1953 British "Totem" tests) did not use what we would call reactor-grade Pu. (In fact, a 1994 analysis of Totem fallout's Pu/Am ratios suggested the shots used WGPu, and the Brits later acknowledged that fuel-grade Pu was planned but was not available at the time.) Emphasis mine. Source? ... What we know is that something freaked out the U.S. government sufficiently in the late 1970s that they technically speaking broke their own laws and the NPT treaty and sent weapons scientists to give classified presentations in countries operating or planning nuclear power. As far as I know, the essence of these presentations was that any Pu can be used in nuclear weapons, and that separated Pu should be guarded as diligently as nuclear weapons. I don't believe this was due to machinations of fossil fuel industry ... As always, interests, not industries, are the things to look at when following money. Late 70s? I thought weapon proliferation as a thing to hobble nuclear energy proliferation began with President Ford being persuaded that the two could sensibly be linked. |
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Post by anonposter on Jul 10, 2012 10:57:00 GMT 9.5
Superphenix was shut down because the French anti-nuclear movement focused basically all of their attention on getting it shut down (and the Greens who held the balance of power at the time demanded it be shut down) as they realised that they had no hope of getting rid of all the reactors.
On the issue of Pu from breeders, France already has the bomb so what does it matter if they can make more bomb grade material? Dealing with proliferation is best done not by hampering the nuclear industry but by removing the need for countries to get the bomb (though complete nuclear disarmament should be opposed, zero is the second worst number of countries to have nuclear weapons).
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Post by Graham Palmer on Jul 10, 2012 11:07:57 GMT 9.5
Quote from Salahodeen Abdul-Kafi: In conclusion, it does not make sense for a country to pursue breeder technology like the Superphenix at this time, considering the relative ease of attaining uranium, as well as the uncertainty in both the technology and proliferation aspects of such a reactor. The link to the Superphenix provides an interesting discussion of the possible rationale of the French program. However, a large part of the discussion is based on a special edition of The Ecologist in 1986, "in conjunction with Friends of the Earth UK" exacteditions.theecologist.org/read/ecologist/vol-16-no-4-5-1986-6476/2/2/This doesn't invalidate the discussion but perhaps puts some context to it. Of interest is that the analysis of China's energy policy on world-nuclear.org states that: By around 2040, PWRs are expected to level off at 200 GWe and fast reactors progressively increase from 2020 to at least 200 GWe by 2050 and 1400 GWe by 2100.www.world-nuclear.org/info/inf63.htmland Russia: In February 2010 the government approved the federal target program designed to bring a new technology platform for the nuclear power industry based on fast reactors. Rosatom's long-term strategy up to 2050 involves moving to inherently safe nuclear plants using fast reactors with a closed fuel cycle. www.world-nuclear.org/info/inf45.htmlIt is clear that China and Russia's long-term motive for fast reactors is energy security before all else - so to some degree, a historical examination of the French program may provide some lessons but doesn't really capture the importance of fast-neutron reactors in coming decades since China and Russia have already worked out that LWR technology won't provide long-term energy security. |
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Post by QuarkingMad on Jul 10, 2012 11:11:05 GMT 9.5
Prof Brook on ABC radio (thanks for the heads-up tweet; link) yesterday discussed this very point on making weapons from spent fuel. What differed in arguments was from which source, military research reactor (no brainier) or civilian baseload plant (unlikely). Before jumping into the technicalities of yield and design, there is one crucial element that many gloss over. There is a saying on the internet that all women in chat rooms are men and all minors in chat rooms are FBI agents. The facilities that Sen. Ludlam noted in Russia that the Americans are helping to make secure are in those ghost cities that the Soviets used to have (existed, but not on a map) who made fuel assemblies and ran reactors for military purposes. To this day outsiders are still noted and pointed out. These people who live there still retain their suspicion of outsiders considering the isolation they lived with during the mid part of their lives. The main threat is not from terrorists gaining access (it's not a shed in the forest you can walk up to). It's from people who lived in these cities trying to make a quick buck on the black market. Back to that saying about the internet, the buyers for Plutonium and Uranium on the black market? Interpol. Not to mention that each border crossing out of Russia has a radiation meter located within. Or for that matter handling it safely. Sourcing radiation sources from medical equipment though...lets not forget what happened in Brazil and Mexico a decade ago. Caused more exposure to harmful levels of radiation than Fukushima ever will on the public. Back onto technical matters, dirty bombs are very easy to clean up as they are not in a widely distributed aerosol. Even the Aum Shinryko attack in Tokyo with chemical agents was ineffective. Chunks can be easily detected and cleaned up with tools, or powdered residue wiped off with a rag. What will get everyone is the misguided fear of the affects. What is more terrifying is not Nuclear terrorism, but bureaucratic mechanisms for state Nuclear weaponry. Came very very close in 1983 (Able Archer), and 1994 (Norwegian rocket) all because of bureaucratic failures. EDIT: Whoops, Anon you are right. Fixed |
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Post by anonposter on Jul 10, 2012 14:16:33 GMT 9.5
Aum used chemical weapons (namely Sarin nerve gas), not biological (not that they weren't working on biological weapons).
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Post by davidm on Jul 23, 2012 11:16:45 GMT 9.5
Going back to the first link I came across this paragraph which I had missed. If uranium is virtually unlimited at a useable price from seawater why is there such a concern for breeding new energy? I get burning the waste but why breeding new energy ie plutonium?
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Post by quokka on Jul 23, 2012 11:51:39 GMT 9.5
David M,
Fast reactors require a much higher level of fissile material in the fuel than do LWRs. I think it's something like 20% enrichment. To start a lot of fast reactors, you need a lot of fissile material to start with. Making it in breeders may well make a lot more sense, especially from an environmental and resource point of view, than mining shed loads of uranium and enriching it leaving simply vast amounts of DU for no good reason.
In a hypothetical world with lots of fast reactors and no need to rapidly expand their numbers, there would not be any reason to make a large excess of Pu.
It's the difference between lots of uranium mining (or sea water extraction) and not much uranium mining.
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Post by David B. Benson on Sept 25, 2012 9:55:26 GMT 9.5
Today's print edition of The New York Times has an article on the US DoE plan to dispose of unwanted U233. It seems that U233 can be used to make a bomb, so my question is can U233 also be used in a fast reactor?
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Post by QuarkingMad on Sept 25, 2012 11:01:11 GMT 9.5
Today's print edition of The New York Times has an article on the US DoE plan to dispose of unwanted U233. It seems that U233 can be used to make a bomb, so my question is can U233 also be used in a fast reactor? is a result of Throium-232 neutron absorption. Technically it can be used in a fast reactor, such as the LFTR, as a result of neutron absorption of the Thorium fuel. U233 can be used to make a bomb, but not an efficient nuclear weapon. The test with U233 and Plutonium sphere was a fizzle (MET test). Not to mention that U233 will often occur with small amounts of U232 which is a strong gamma emitter. Extensive shielding and remote handling is required. It's not a nice isotope, but can be managed safely in the right concentrations. |
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Post by LancedDendrite on Sept 25, 2012 11:10:55 GMT 9.5
U-233 can be used in a fast reactor, but it is much more efficiently burnt up in a thermal-spectrum reactor, like U-235.
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Post by grlcowan on Sept 27, 2012 5:12:06 GMT 9.5
U233 can be used to make a bomb, but not an efficient nuclear weapon. The test with U233 and Plutonium sphere was a fizzle (MET test). Not to mention that U233 will often occur with small amounts of U232 which is a strong gamma emitter. Extensive shielding and remote handling is required. It's not a nice isotope, but can be managed safely in the right concentrations. The page linked with the word "fizzle" has this to say about an explosion of 233-U: The predicted yield was 33 kt. The actual 22 kt was 33% below this ... I don't think that's a fizzle. Also, I don't recall who said the LFTR is a fast reactor, but that's incorrect. It is moderated by fluorine, of course; by lithium and beryllium; and by carbon. |
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Post by QuarkingMad on Sept 27, 2012 10:52:44 GMT 9.5
U233 can be used to make a bomb, but not an efficient nuclear weapon. The test with U233 and Plutonium sphere was a fizzle (MET test). Not to mention that U233 will often occur with small amounts of U232 which is a strong gamma emitter. Extensive shielding and remote handling is required. It's not a nice isotope, but can be managed safely in the right concentrations. The page linked with the word "fizzle" has this to say about an explosion of 233-U: The predicted yield was 33 kt. The actual 22 kt was 33% below this ... I don't think that's a fizzle. Also, I don't recall who said the LFTR is a fast reactor, but that's incorrect. It is moderated by fluorine, of course; by lithium and beryllium; and by carbon. The full paragraph: The primary purpose was to evaluate the destructive effects of nuclear explosions for military purposes. For this reason, the DOD specified that a device must be used that had a yield calibrated to within +/- 10%, and the Buster Easy device design was selected (this test gave 31 kt and used a plutonium/U-235 core). LASL weapon designers however decided to conduct a weapon design experiment with this shot, and unbeknownst to the test effect personnel substituted the untried U-233 core. The predicted yield was 33 kt. The actual 22 kt was 33% below this, seriously compromising the data collectedA fizzle in nuclear testing is if the bomb does not reach the expected yield, this was short by 33%, thus a fizzle. Even considering the +/-10% error margin. This does not deny that it still was an explosion that did cause damage. Although the bomb was primarily a plutonium device, and other tests with Pu/U235 core worked as planned at the expected yields. Using U233 in a bomb is inefficient, and a deviation away from the methodology of processing of U235. Why deviate away from a tested and proven bomb material? |
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Post by Roger Clifton on Sept 28, 2012 17:37:07 GMT 9.5
U232 is a neutron emitter, as it does have a spontaneous fission mode of decay. I don't know whether there is enough neutron flux to disable the machinists before they have completed their metal work. However any neutrons emitted during the compression stage would make for an earlier detonation, reducing the yield.
There is a strong gamma emitted by its daughter Tl208, months later, but that just means you shouldn't play with old bombs. Heck, someone might get hurt.
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Post by Janne M. Korhonen on Sept 28, 2012 21:11:35 GMT 9.5
My apologies, I forgot to reply to this. ... It does seem likely that the published tests that may have used below weapons grade Pu (the 1962 U.S. test and 1953 British "Totem" tests) did not use what we would call reactor-grade Pu. (In fact, a 1994 analysis of Totem fallout's Pu/Am ratios suggested the shots used WGPu, and the Brits later acknowledged that fuel-grade Pu was planned but was not available at the time.) Emphasis mine. Source? The Pu/Am analysis is in P.A. Burns et al., Health Physics 67, 1994, pp.226-232. I found the info and a mention about the Brits acknowledging the non-use of fuel-grade Pu from www.foe.org.au/anti-nuclear/issues/nfc/power-weapons/rgpu/which I think may be considered credible source for this information, as it would benefit our dear FOE to pretend fuel-grade Pu was actually used. Of course, your mileage may vary. ... What we know is that something freaked out the U.S. government sufficiently in the late 1970s that they technically speaking broke their own laws and the NPT treaty and sent weapons scientists to give classified presentations in countries operating or planning nuclear power. As far as I know, the essence of these presentations was that any Pu can be used in nuclear weapons, and that separated Pu should be guarded as diligently as nuclear weapons. I don't believe this was due to machinations of fossil fuel industry ... As always, interests, not industries, are the things to look at when following money. Late 70s? I thought weapon proliferation as a thing to hobble nuclear energy proliferation began with President Ford being persuaded that the two could sensibly be linked. That's possible. My interpretation of the events is based on a reading of local (Finnish) sources and certain informal discussions; they suggest that the possibility of using Pu from civilian reactors in nuclear weapons was independently suggested by civilian research dating from about 1970, and hint that the reason why the U.S. weapon scientists were sent to brief nuclear energy regulators (as I said, in a technical breach of the U.S. Atomic Energy Act if I've understood things correctly) might be that there's something the U.S. weapons labs know but can't tell. Of course, this is not incompatible with certain special interests or just plain stupidity. But my interpretation is not much more than conjecture, and I unfortunately failed to note the sources for the above. Will try to look into the matter more in the future. |
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Post by Roger Clifton on Sept 29, 2012 15:50:27 GMT 9.5
The paper (above) on the Friends of Earth site reads as if an academically respectable work, drawing heavily on a paper by Carlson et al to condemn reactor grade plutonium as a proliferation risk. However, the link quoted for that paper, to an Australian government site, fails, and IAEA site cannot find the paper either. Instead a paper of that name and authors can be found at www.fas.org/nuke/intro/nuke/O_9705.htmon the site of the Federation of American Scientists, who state their mission as the prevention of nuclear war. www.fas.org/about/Although still quite respectable, it turns out the paper is actually about the greater hazard of accumulating low-burnup plutonium, and concludes with recommendations including "existing stocks of unirradiated low burn up plutonium would be diverted, or given priority for fuel fabrication, or permanently disposed of". We know that this could be achieved by diverting all such plutonium into fast reactor fuel. Once loaded in the core of a fast neutron reactor, plutonium is quickly irradiated, and continues to be irradiated until it is burnt up. Unlike plutonium in a store, the fuel in a fast reactor is under continuous scrutiny by a range of professionals throughout its shortened life. Once again, FoE is shouting "wha' abaht the waste!" and once again, the answer is "recycle the stuff!". |
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Post by amorylovins on Sept 30, 2012 16:01:30 GMT 9.5
It appears that most of the correspondents on this thread are unfamiliar with several decades of professional literature on the subject (and not only from my friends Dick Garwin and the late Carson Mark). The weapons labs, top weapons experts, and Department of Energy have published unambiguous official statements about the proliferation dangers of high-burnup Pu. The physical reasoning behind those statements is discreetly outlined in my *Nature* review paper of 28 Feb 1980, posted free at www.rmi.org/Knowledge-Center/Library/S80-01_NuclearWeaponsPowerReactorPlutonium. (Incidentally Dr. Mark was LANL's senior classification reviewer on that review paper.) Those who continue to assert that high-burnup Pu is of little or no military utility, and who post false arguments to this effect in places like Wikipedia to mislead a new generation of the credulous (often by impugning the integrity of the weapons scientists who have publicly refuted their claims), should be ashamed of themselves. --Amory B. Lovins, Chairman and Chief Scientist Rocky Mountain Institute |
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Post by QuarkingMad on Sept 30, 2012 16:44:10 GMT 9.5
That is an interesting read. However your link is broken as there is a rouge period at the end of the link, the following should work: www.rmi.org/Knowledge-Center/Library/S80-01_NuclearWeaponsPowerReactorPlutoniumMy only critique is that will a nation such as Australia divert plutonium away from a civilian generating reactor to make a bomb, whether it be yield accurate or not. We have a medical isotope reactor that would be better suited to this task, but the government or the defence force has not done so. This was a key criticism of the Lucas Heights reactor that in theory (academia) could happen, but in reality it is highly unlikely. I feel as if it is an exercise in academia, rather than in reality. It is possible to do with technological fixes and knowledge (as noted in your report), but is there the desire to? These sort of arguments while valid are not applicable to a nation such as Australia mulling the Nuclear power option. Keeping in the back of mind, yes, but applying it to the debate on whether to pursue nuclear power for electricity generation in Australia, no. |
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Post by Roger Clifton on Sept 30, 2012 20:15:16 GMT 9.5
As AmoryLovins says, -- there is indeed a lot of literature talking about the "proliferation dangers of high-burn up plutonium", even some of them suggest that some tooled-up nuclear weapons state could actually manage to detonate one. However that hypothetical event would not change the conclusion that "high-burn up plutonium is of little or no military utility". Those of us who are concerned for the environment of our successors have something far more serious to worry about: carbon pollution from non-nuclear power sources.
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Post by David B. Benson on Oct 2, 2012 8:27:52 GMT 9.5
What is high burnup plutonium?
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Post by Roger Clifton on Oct 2, 2012 17:54:36 GMT 9.5
@david B Benson asks, "what is high burnup plutonium"?
It would perhaps be more accurate to say "plutonium from high-burnup fuel". Fresh fuel in a reactor firstly builds up plutonium 239, then with more exposure to the neutron flux, some of the plutonium 239 converts to plutonium 240. Other isotopes are being formed as well.
Whereas plutonium 239 can be handled with minimum protection (Queen Elizabeth was once presented with a ball of plutonium 239 to hold so she could feel its warmth), the plutonium 240 has a much higher neutron emission from its higher spontaneous fission rate that is said to deter theft.
High-and low-burnup are concepts applied to used fuel from slow neutron reactors . In a fast neutron reactor, the fuel is burnt much harder and can be (in principle) recycled to complete burnup.
Wikipedia entry on burnup will tell you more.
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Post by grlcowan on Oct 3, 2012 5:49:07 GMT 9.5
... plutonium 240 has a much higher neutron emission from its higher spontaneous fission rate that is said to deter theft Theft by bomb-seekers would not, I think, be discouraged by this. If they could be so easily discouraged, other radiations emitted by fission fragments would, to a much greater degree, discourage them from building their own small, secret reactors, as Syria is reputed recently to have done (but failed to keep secret from the Israelis). But if you want a Pu bomb, you presumably want to know it will almost certainly explode much more energetically than an equal volume of TNT, and the frequent creation of 240-Pu neutrons in a mass of plutonium that contains a lot of this isotope means that as you shrink it as fast as possible, a 240-Pu neutron is likely to start the chain reaction when the mass is only slightly prompt-supercritical. This raises the temperature to a few thousand K within a few microseconds, stopping and reversing the shrinkage (since the shrinkage is being driven by pressure from chemicals that, in exploding, have raised themselves to a few kilokelvins). This prematurely ends the supercriticality with the yield limited to an amount determined by the heat capacity of the bomb materials -- chemical and nuclear explosive both -- between room temperature and a few kilokelvins. But if the chemical explosion can continue driving the shrinkage, with the plutonium remaining inert, because no initiating neutrons turn up, until the volume reaches a minimum, and only then are neutrons deliberately added, the chain reaction can start when the mass is deeply prompt-supercritical. Many generations of neutrons, each maybe twice as numerous as the one before, can be created in less than one microsecond, and there can be enough of them to heat the mass much hotter than the sun's core before it can expand itself to subcriticality. That's as clear as I can make the tricky process that plutonium-240 bollixes. If my understanding and prose are adequate, maybe I've made it unsurprising that Nature produced fission reactors, but no fission explosions, and the use of high-burnup power reactor plutonium in bombs has remained theoretical. |
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