just 1.6 tonnes of thorium metal would be enough to produce 8kg of uranium-233 which is the minimum amount required for a nuclear weapon.
”Small-scale chemical reprocessing of irradiated thorium can create an isotope of uranium – uranium-233 – that could be used in nuclear weapons. If nothing else, this raises a serious proliferation concern.”
Thorium: Proliferation warnings on nuclear ‘wonder-fuel’ , Phys Org, December 5, 2012Thorium is being touted as an ideal fuel for a new generation of nuclear power plants, but in a piece in this week’s Nature, researchers suggest it may not be as benign as portrayed.
The element thorium, which many regard as a potential nuclear “wonder-fuel”, could be a greater proliferation threat than previously thought, scientists have warned. Writing in a Comment piece in the new issue of the journal, Nature, nuclear energy specialists from four British universities suggest that, although thorium has been promoted as a superior fuel for future nuclear energy generation, it should not be regarded as inherently proliferation resistant.
The piece highlights ways in which small quantities of uranium-233, a material useable in nuclear weapons, could be produced covertly from thorium, by chemically separating another isotope, protactinium-233, during its formation. The chemical processes that are needed for protactinium separation could possibly be undertaken using standard lab equipment, potentially allowing it to happen in secret, and beyond the oversight of organisations such as the International Atomic Energy Agency (IAEA), the paper says.
The authors note that, from previous experiments to separate protactinium-233, it is feasible that just 1.6 tonnes of thorium metal would be enough to produce 8kg of uranium-233 which is the minimum amount required for a nuclear weapon. Using the process identified in their paper, they add that this could be done “in less than a year.”….. Dr Steve Ashley, from the Department of Engineering at the University of Cambridge and the paper’s lead author, said. “Small-scale chemical reprocessing of irradiated thorium can create an isotope of uranium – uranium-233 – that could be used in nuclear weapons. If nothing else, this raises a serious proliferation concern.”
Thorium Nuclear Bombs (Shorter version) Kevin Meyerson, kevinmeyerson.wordpress.com 9 Oct 12, Thorium bred Uranium-233 can be used to make atomic bombs, despite what proponents may claim.
You don’t have to trust me on this, see what the experts at various institutions have to say below:
Appendix A starts on page 181 of the Appendices PDF file. The relevant statement from MIT is:
- Proliferation And Security Groundrules:
Irradiating thorium produces weapons-useable material. Policy decisions on appropriate ground rules are required before devoting significant resources toward such fuel cycles. U-233 can be treated two ways.
- Analogous to U-235. If the U-235 content of uranium is less than 20% U-235 or less than 13% U-233 with the remainder being U-238, the uranium mixture is non-weapons material. However, isotopic dilution in U-238 can significantly compromise many of the benefits.
- Analogous to plutonium. Plutonium can not be degraded thus enhanced safeguards are used. The same strategy can be used with U-233. A complicating factor (see below) is that U-233 is always contaminated with U-232 that has decay products that give off high energy gamma radiation which requires additional measures to protect worker health and safety. There has been no consensus on the safeguards / nonproliferation benefits of this radiation field.
The point being made here is that thorium can be used to make Uranium-233, which in turn can be used to make bombs. The complicating U-232 contamination mentioned above is what many of the thorium proponents refer to as making thorium resistant to proliferation. MIT has more to say about this proliferation protection in their summary:
On one hand, high radiation dose [from U-232 decay] provides self protection to separated fissile material against diversion and misuse. On the other hand, it makes the U-233 recycling more complex and costly.
The point here is that the U-233 is in fact subject to ‘diversion and misuse’ (like atomic bombs) if it can be separated out from the highly radioactive U-232 contaminants. If the U-232 is not somehow processed out, however, there is no way to operate the reactor for peaceful purposes, or otherwise.
Filtering contaminants out of thorium bred U-233 to make weapons grade fissile material is not rocket science. Oak Ridge National Laboratory (ORNL) created a process to do this. They kindly wrote about it in a history included in the ORNL Review publication (search the long page for the words “THOREX” or “Uranium-233″):
By 1954, the Laboratory’s chemical technologists had completed a pilot plant demonstrating the ability of the THOREX process to separate thorium, protactinium, and uranium-233 from fission products and from each other. This process could isolate uranium-233 for weapons development and also for use as fuel in the proposed thorium breeder reactors.
There are no technical issues for separating out Uranium-233 for weapons development.
The United Kingdom’s National Nuclear Laboratory (NNL) prepared a position paper on the thorium nuclear fuel cycle. It is pretty straightforward:
Contrary to that which many proponents of thorium claim, U-233 should be regarded as posing a definite proliferation risk.For a thorium fuel cycle which falls short of a breeding cycle, uranium fuel would always be needed to supplement the fissile material and there will always be significant (though reduced) plutonium production.
NNL believes that U-233 should be regarded as posing a comparable level of proliferation risk to High Enriched Uranium (HEU) and comparable with the U-Pu fuel cycle at best; this view is consistent with the IAEA, who under the Convention on the Physical Protection of Nuclear Materials, categorise U-233 on the same basis as plutonium. Attempts to lower the fissile content of uranium by adding U-238 are considered to offer only weak protection, as the U-233 could be separated in a centrifuge cascade in the same way that U-235 is separated from U-238 in the standard uranium fuel cycle.
The argument that the high U-232 content would be self- protecting are considered to be over-stated. NNL’s view is that thorium systems are no more proliferation resistant than U-Pu systems though they may offer limited benefits in some circumstances.
Here are some comments from other resources:
Oak Ridge National Labs U-233 Disposition Project Update (PDF, see page 3)
- U-233 has nuclear properties similar to weapons-grade plutonium, but the chemistry of uranium
- High specific alpha activity (inhalation hazard)
- Weapons-usable fissile nuclear material requiring strict safeguards, tight security, and criticality control……… http://kevinmeyerson.wordpress.com/2012/05/07/thorium-nuclear-bombs-short-version/
One reason reprocessing thorium fuel cycles haven’t been successful is that uranium-232 (U-232) is created along with uranium-233. U-232, which has a half-life of about 70 years, is extremely radioactive and is therefore very dangerous in small quantities:
Thorium Fuel: No Panacea for Nuclear Power, http://ieer.org/wp/wp-content/uploads/2012/04/thorium2009factsheet.pdf By Arjun Makhijani and Michele Boyd A Fact Sheet Produced by the Institute for Energy and Environmental Research and Physicians for Social Responsibility
Thorium “fuel” has been proposed as an alternative to uranium fuel in nuclear reactors. There are not “thorium reactors,” but rather proposals to use thorium as a “fuel” in different types of reactors, including existing light-water reactors and various fast breeder Read more »
Thinking About Thorium by Gordon Edwards, Ph.D., President of CCNR, September 16 2012 On CBC’s “Quirks and Quarks” radio program aired on Saturday, September 15, 2012, there was an enthusiastic endorsement of “thorium reactors” as a nearly miraculous form of nuclear energy that will avoid all of the major problems now associated with uranium-based nuclear power.
I have been asked by several people to give my own personal opinion of this prospect, and accordingly have written the following:
When nuclear power was first presented to a credulous public, fully conditioned to respect science and admire scientists, people were quick to believe that nuclear power was safe, clean, cheap and inexhaustible — just because scientists said so. It was also said that “peaceful” nuclear power had nothing whatsoever to do with atomic bombs and the proliferation of nuclear weapons. It took decades for people to realize that these are all lies.
I can’t believe that people are now so eager to swallow the hype about thorium with all its over-the-top claims of being safe, clean, cheap, inexhaustible, unrelated to nuclear weapons, and even a miraculous way of solving the nuclear waste problems created by the previous generation of — what? — safe, clean, cheap, inexhaustible, unrelated to nuclear weapons, nuclear reactors.
As the old saying goes, “once burned, twice shy”. Or more explicitly, “Fool me once, same on you. Fool me twice, shame on me.” Read more »
the fission products from a Thorium reactor are a worry, Technetium-99 has a half life of 220,000 years, uranium-232 produces thallium-208 (a nasty wee gamma emitter), Selenium-79 (another gamma emitter with a 327,000 year half-life), evenThorium-232 is a problem with its half life of 14 Billion years (and while the T-232 isn’t a major worry, all the time during this 14 Billion years it will be decaying and producing stuff that is!).
Thorium Cycle questions and problems http://daryanenergyblog.wordpress.com/ca/part-8-msr-lftr/8-3-thorium-lftr/ Questions have also been raised by some nuclear scientists about the Thorium cycle, in particular the proposed one that the LFTR would use. I’m not a nuclear physicist so I’ll merely forward you on to the relevant paper here , and a rebuttal here . The crux of the argument seems to be the proliferation risk (I’ll come back to that one later), the fact that a number of its spend fuel outputs (such as Technetium-99) are “nasty stuff” with a long half life and the fact we’ll still need supplies of Uranium to get Thorium reactors going again whenever we have to turn it off (which will happen at least once a year or so during its annual maintenance shutdown). They also highlight a number of technical issues, which I discussed in the chapter on HTGR’s.
Certainly the fission products from a Thorium reactor are a worry, Technetium-99 has a half life of 220,000 years, uranium-232 produces thallium-208 (a nasty wee gamma emitter), Selenium-79 (another gamma emitter with a 327,000 year half-life), evenThorium-232 is a problem with its half life of 14 Billion years (and while the T-232 isn’t a major worry, all the time during this 14 Billion years it will be decaying and producing stuff that is!).
The UK based NNL (National Nuclear Laboratories) also pour cold water on the idea of Thorium fuelled reactors (see here ). While the report is low on detail (they seem to be saying “trust us we’re scientists who work with nuke stuff… and we smoke pipes!”) they do highlight the major time delays it would take to establish and get working a Thorium fuel cycle (10-15 years with existing reactors, 30 with more advanced options), point out that under present market conditions its unlikely to be economically viable and will (as the points above raise) offer only a modest reduction in nuclear wastes.
MIT recently undertook a study of future nuclear fuel supplies. The Thorium cycle barely gets a mention, and even then its usually in relation to Fast Reactor programs (of which the US currently has none) and modifed LWR systems, rather than the MSR.
Obviously, once we exhaust the world’s U-235 stockpiles, LFTR’s and any other Thorium fuelled reactors will cease to function. Indeed long before then the spike in Uranium prices will have rendered MSR’s (and all other nuclear plants) uneconomically viable (of course there’s plenty who’d say that’s already the case!). The LFTR fans usually groan at this point and state that “all we need is a little plutonium”. Now while I’m quite sure that in the fantasy world which the LFTR fans inhabit Plutonium is available in any good hardware store but back in the real world, it’s a little harder to come by! As with the HTGR’s using Thorium (if its possible) would certainly help stretch things out….a bit! But not by nearly as much as the supporters of Thorium reactors would have you believe.
thorium is merely a way of deflecting attention and criticism from the dangers of the uranium fuel cycle and excusing the pumping of more money into the industry….. the nuclear industry itself is also sceptical
‘ these arereally U-233 reactors,’ This isotope is more hazardous than the U-235 used in conventional reactors, he adds, because it produces U-232 as a side effect (half life: 160,000 years), on top of familiar fission by-products
Don’t believe the spin on thorium being a ‘greener’ nuclear option Ecologist, Eifion Rees 23rd June, 2011 It produces less radioactive waste and more power than uranium but the UK would be making a mistake in looking to it as a ’greener’ fuel. The Ecologist reports….. nuclear radiologist Peter Karamoskos, of the International Campaign to Abolish Nuclear Weapons (ICAN), says the world shouldn’t hold its breath.
‘Without exception, [thorium reactors] have never been commercially viable, nor do any of the intended new designs even remotely seem to be viable. Like all nuclear power production they rely on extensive taxpayer subsidies; the only difference is that with thorium and other breeder reactors these are of an order of magnitude greater, which is why no government has ever continued their funding.’ Read more »
A pro-nuclear engineer let slip to me a while ago the real attiude of the nuke industry to Thorium. They see it as hedging their bets in case fusion proves to be harder than they thought and they don’t get commercial grade fusion plants up and running by the 2050′s. If that occurs, then that’s when Thorium (or LFTR’s) will figure. In other words, to them its a blue sky idea to sort out a future energy crisis, not the one facing us right now. This is why you see a vast gulf of a difference between pro-Thorium bloggers and the nuclear industry establishment.
Thorium: Not ‘green’, not ‘viable’, and not likely
Journalist, Oliver Tickell, author of the Kyoto2 climate initiative, (1) editor of the Nuclear Pledge website (2) and Green Party candidate for Oxford City Council in three elections, has published a new briefing on Thorium reactors.
A number of commentators have argued that most of the problems associated with nuclear power could be avoided by both, using thorium fuel in place of uranium or plutonium fuels and using ‘molten salt reactors’ (MSRs) in place of conventional solid fuel reactor designs. The combination of these two technologies is known as the Liquid Fluoride Thori um Reactor or LFTR, because the fuel is in form of a molten fluoride salt of thorium and other elements.
The briefing examines the validity of the optimistic claims made for thorium fuel, MSRs and the LFTR in particular, and finds that they do not stand up to critical scrutiny – these technologies have significant drawbacks including: very high costs; marginal benefits for a thorium fuel cycle over uranium; serious nuclear weapons proliferation hazards; the danger of both routine and accidental releases of radiation, mainly from continuous ‘live’ fuel reprocessing in MSRs and the very long lead time for significant deployment of LFTRs of perhaps 50 years – rendering it irrelevant in terms of addressing current or medium term energy supply needs.
The thorium-uranium fuel cycle has some advantages over the dominant uranium-plutonium cycle, in terms for example, of the reduced production of long-lived actinides and somewhat diminished radio -toxicity overall. However, it also creates new hazards of its own. As far as radioactive fission products are concerned, there is little to choose between the two.
Thorium reactors do not produce plutonium. But an LFTR could (by including 238U in the fuel) be adapted to produce plutonium of a high purity well above normal weapons-grade, presenting a major proliferation hazard. Beyond that, the main proliferation hazards arise from the need for fissile material (plutonium or uranium) to initiate the thorium fuel cycle, which could be diverted, and the production of fissile uranium 233U.
LFTRs are theoretically capable of a high fuel burn-up rate, but while this may indeed reduce the volume of waste, the waste is more radioactive due to the higher volume of radioactive fission products. The continuous fuel reprocessing that is characteristic of LFTRs will also produce hazardous chemical and radioactive waste streams, and releases to the environment will be unavoidable. Spent fuel from any LFTR will be intensely radioactive and constitute high level waste. The reactor itself, at the end of its lifetime, will constitute high level waste.
The UK’s National Nuclear Laboratory (NNL) believes that considerable research, development and testing lies ahead before thorium fuels will be ready for operational use. As the NNL states, “Thorium reprocessing and waste management are poorly understood. The thorium fuel cycle cannot be considered to be mature in any area.” It estimates that 10-15 years work is required before thorium fuels will be ready for use in current reactor designs, and that their use in new types of reactor is at least 40 years away. (3)
(3) Thorium: Not Green, Not Viable and Not Likely, Oliver Tickell, June 2012
- 1 NUCLEAR ISSUES
- civil liberties
- Depleted uranium
- global warming
- Opposition to nuclear
- safety and incidents
- secrets and lies
- NUCLEAR COMPANIES
- 1 NUCLEAR ISSUES