A Silly Way To Boil Water 94


As regular readers know, I have been involved with a company installing gas turbines in Ghana. Our next plan is to collect the exhaust heat, generate steam from it, and feed that into a steam turbine to generate more electricity for no added fuel cost.

That is a sensible way to boil water. It can go wrong – any large machine operating with high forces can do damage. But even the worst disaster would be localised and over in an instant.

All nuclear power stations do is to boil water to make steam for a steam turbine. Given the massively disproportionate potential forces at play, the capacity for a Chernobyl style disaster killing thousands, and the long term dangers from nuclear waste, that really is a very very silly – and enormously expensive – way to boil water. You have to be slightly deranged to see nuclear power as sensible.

Those massively disproportionate potential forces in play lead to nuclear power always bringing in its train government lies, secrecy, restrictions on liberty and increase in state power. For those reasons politicians find it attractive. As it involves massive capital cost, there is a big industry lobby that backs it. As many of the full costs are met by the state, the corruption possibilities are good too. That is why the lobby for this crazed option is so strong.

Here is another better way to boil water:

Within 6 hours deserts receive more energy from the sun than humankind consumes within a year. An area of around the size of a living room, covered by mirrors for concentrating solar thermal power plants, would suffice to cover the electricity need of one person day and night – carbon free.

Thanks to Ingo for the desertec link.


94 thoughts on “A Silly Way To Boil Water

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  • Anon

    http://www.ornl.gov/info/ornlreview/rev25-34/chapter4.shtml

    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.

  • Anon

    http://energyfromthorium.com/msrp/ornl4191/ (bit ironic that source)
    .
    ORNL-4191: Aug 1967 Progress Report
    .
    MOLTEN-SALT REACTOR PROGRAM
    SEMIANNUAL PROGRESS REPORT
    For Period Ending August 31, 1967
    .
    …SEPARATION OF FISSION PRODUCTS AND OF PROTACTINIUM FROM MOLTEN FLUORIDES
    .
    12.1 Extraction of Protactinium from Molten Fluorides into Molten Metals

  • Anon

    I had better add, my interest is in ZERO PROLIFERATION (or as near to it as possible). U233 is horrible stuff. If I had the slightest interest in anything bad, this would be one of the very last blogs I would post on!

  • Clark

    So it looks like MSRs were passed over for being too good for export, and now there’s a misdirection about just how good they are? That would virtually guarantee that secret MSRs exist, I’d say. It is looking like an extremely versatile integrated nuclear/chemical reaction environment.

  • Clark

    Yes, I know energyfromthorium.com. It’s Kirk Sorenson’s site; he’s trying to set up a company, Flibe Energy, to produce small MSRs, and yes, his non-proliferation claim is that U-233 would “inevitably” be contaminated with U-232.
    .
    He also has a huge trove of documents concerning ONRL’s Molten Salt Reactor Experiment. Have you looked through them?
    .
    From your excerpt above (sgs09kang.pdf), it seems that an MSR could easily produce weapons grade U-233 for whoever had control of the reactor, but that it would be difficult for another party to steal or divert the material.

  • Anon

    I’m sure India is trustworthy. Never shown any desire to develop clandestine weapons after all.
    .
    No production MSR design exists so it is impossible to say what a third part might, or might not do, with however it might work in reality.
    .
    Some, but not all, of the Thorium cycle proponents expect it will never exist in reality in great numbers – IMHO.
    .
    If fossil fuels are peaking and other choices are too dangerous, what will we do?

  • Anon

    Exercise for reader.

    Bombs approaching 1 megaton have been demonstrated with U-235. What sort of yield might be possible with a practical U-233 pure fission bomb?
    .
    Good Night.

  • Clark

    Anon, when you say “my interest is in ZERO PROLIFERATION”, do you mean weapons, power generation, medical, research, all of these, etc?
    .
    My own interest is finding out more. I need to do that before I can take a position. MSR technology first interested me because of claims that it could burn up the “spent fuel” stockpile into fission products. This is another claim that I wish to examine.

  • Anon

    Principally weapons. The possibility of burning waste in reactors is appealing but the software exists today to run fuel burn simulations . Once someone comes up with a proposed production design and fully simulated fuel cycle that meets all the claims, then we will have something to go on.
    .
    For now it is all jut hot air and perhaps always will be.

  • Clark

    OK, so what burnup simulations have been run, and which of those looks most promising? My thinking is that we already have large quantities of “spent” fuel, and it looks as though burning it in a reactor is the only way to get rid of it in any reasonable time scale. That will inevitably generate heat, which may as well be put to good use. Or is there some disposal method that you think is preferable?
    .
    What do think are the key points in non-proliferation? Is it possible to build secret reactors, or are they really difficult to hide?

  • Anon

    Clark,
    .
    In theory there is this. That’s if it doesn’t blow itself up.
    .
    http://www.utexas.edu/news/2009/01/27/nuclear_hybrid/
    .
    Nuclear Fusion-Fission Hybrid Could Destroy Nuclear Waste and Contribute to Carbon-Free Energy Future
    .

    .AUSTIN, Texas — Physicists at The University of Texas at Austin have designed a new system that, when fully developed, would use fusion to eliminate most of the transuranic waste produced by nuclear power plants.
    .
    “We have created a way to use fusion to relatively inexpensively destroy the waste from nuclear fission,” says Mike Kotschenreuther, senior research scientist with the Institute for Fusion Studies (IFS) and Department of Physics. “Our waste destruction system, we believe, will allow nuclear power—a low carbon source of energy—to take its place in helping us combat global warming.”
    .
    Toxic nuclear waste is stored at sites around the U.S. Debate surrounds the construction of a large-scale geological storage site at Yucca Mountain in Nevada, which many maintain is costly and dangerous. The storage capacity of Yucca Mountain, which is not expected to open until 2020, is set at 77,000 tons. The amount of nuclear waste generated by the U.S. will exceed this amount by 2010.
    .
    The physicists’ new invention could drastically decrease the need for any additional or expanded geological repositories.
    .
    Most people cite nuclear waste as the main reason they oppose nuclear fission as a source of power,” says Swadesh Mahajan, senior research scientist.
    .
    The scientists propose destroying the waste using a fusion-fission hybrid reactor, the centerpiece of which is a high power Compact Fusion Neutron Source (CFNS) made possible by a crucial invention.
    .
    The CFNS would provide abundant neutrons through fusion to a surrounding fission blanket that uses transuranic waste as nuclear fuel. The fusion-produced neutrons augment the fission reaction, imparting efficiency and stability to the waste incineration process.
    .
    Kotschenreuther, Mahajan and Prashant Valanju, of the IFS, and Erich Schneider of the Department of Mechanical Engineering report their new system for nuclear waste destruction in the journal Fusion Engineering and Design.
    .
    There are more than 100 fission reactors, called “light water reactors” (LWRs), producing power in the United States. The nuclear waste from these reactors is stored and not reprocessed. (Some other countries, such as France and Japan, do reprocess the waste.)
    .
    The scientists’ waste destruction system would work in two major steps.
    .
    First, 75 percent of the original reactor waste is destroyed in standard, relatively inexpensive LWRs. This step produces energy, but it does not destroy highly radiotoxic, transuranic, long-lived waste, what the scientists call “sludge.
    .
    In the second step, the sludge would be destroyed in a CFNS-based fusion-fission hybrid. The hybrid’s potential lies in its ability to burn this hazardous sludge, which cannot be stably burnt in conventional systems.
    .
    To burn this really hard to burn sludge, you really need to hit it with a sledgehammer, and that’s what we have invented here,” says Kotschenreuther.
    .
    One hybrid would be needed to destroy the waste produced by 10 to 15 LWRs.
    .
    The process would ultimately reduce the transuranic waste from the original fission reactors by up to 99 percent. Burning that waste also produces energy.
    .
    The CFNS is designed to be no larger than a small room, and much fewer of the devices would be needed compared to other schemes that are being investigated for similar processes. In combination with the substantial decrease in the need for geological storage, the CFNS-enabled waste-destruction system would be much cheaper and faster than other routes, say the scientists.
    .
    The CFNS is based on a tokamak, which is a machine with a “magnetic bottle” that is highly successful in confining high temperature (more than 100 million degrees Celsius) fusion plasmas for sufficiently long times.
    .
    The crucial invention that would pave the way for a CFNS is called the Super X Divertor. The Super X Divertor is designed to handle the enormous heat and particle fluxes peculiar to compact devices; it would enable the CFNS to safely produce large amounts of neutrons without destroying the system.
    .
    The intense heat generated in a nuclear fusion device can literally destroy the walls of the machine,” says research scientist Valanju, “and that is the thing that has been holding back a highly compact source of nuclear fusion.”
    .
    Valanju says a fusion-fission hybrid reactor has been an idea in the physics community for a long time.
    .
    “It’s always been known that fusion is good at producing neutrons and fission is good at making energy,” he says. “Now, we have shown that we can get fusion to produce a lot of neutrons in a small space.”
    .
    Producing an abundant and clean source of “pure fusion energy” continues to be a goal for fusion researchers. But the physicists say that harnessing the other product of fusion—neutrons—can be achieved in the near term.
    .
    In moving their hybrid from concept into production, the scientists hope to make nuclear energy a more viable alternative to coal and oil while waiting for renewables like solar and pure fusion to ramp up.
    .
    “The hybrid we designed should be viewed as a bridge technology,” says Mahajan. “Through the hybrid, we can bring fusion via neutrons to the service of the energy sector today. We can hopefully make a major contribution to the carbon-free mix dictated by the 2050 time scale set by global warming scientists.”
    .
    The scientists say their Super X Divertor invention has already gained acceptance in the fusion community. Several groups are considering implemented the Super X Divertor on their machines, including the MAST tokamak in the United Kingdom, and the DIIID (General Atomics) and NSTX (Princeton University) in the U.S. Next steps will include performing extended simulations, transforming the concept into an engineering project, and seeking funding for building a prototype.
    .
    For more information, contact: Lee Clippard, College of Natural Sciences, 512-232-0675; Dr. Mike Kotschenreuther, 512-471-1322; Dr. Swadesh Mahajan, 512-471-4376.

    Tags: Research, alternative energy, climate change, Cockrell School of Engineering, College of Natural Sciences, Department of Mechanical Engineering, Department of Physics, Erich Schneider, fission, fusion, global warming, Institute for Fusion Studies, light water reactors, Mike Kotschenreuther, nuclear energy, nuclear waste, Prashant Valanju, renewable energy, Swadesh Mahajan, Yucca Mountain
    ==================================================
    .
    What could possibly go wrong? 🙂

  • Anon

    Secret reactors? Can’t see any reason why you couldn’t build them. It’s not as if the IAEA is going to stick its nose in unless you are one of a small select group of countries. As long as you didn’t get it horribly wrong and announce its presence to the world that way. These types of reactors don’t have to be at anything like Gigawatt thermal power levels after all as they are not powering a city.

  • Anon

    And talking of nuclear reactors in strange places…
    http://en.wikipedia.org/wiki/JASON_reactor
    ..
    JASON reactor
    .
    JASON was a nuclear reactor installed by the Ministry of Defence at the Royal Naval College in Greenwich, London.
    .
    It was an Argonaut series 10 kW research reactor designed by the US Argonne National Laboratory, and was used by the Royal Navy for experimental and training purposes. The actual reactor type used in the Royal Navy’s nuclear powered submarines is a pressurised water reactor (PWR) supplying tens of megawatts of power.
    .
    JASON was operational at the site from 1962 to 1996 (it had previously been operated by the Hawker Siddeley Nuclear Power Corporation from February 1959 at Langley, Slough), and fully dismantled by 1999. 270 tonnes of radioactive waste was removed.
    .
    JASON was one of very few reactors operating within a major population centre – and undoubtedly the only one installed in a 17th century building. The Royal Naval College building was the former Greenwich Hospital, built between 1696 and 1712 by Christopher Wren, where the reactor was located within the King William Building. The existence of a nuclear reactor so close to central London was largely unknown to the general public, even at the time that “Maritime Greenwich” was named a UNESCO World Heritage Site in 1997.
    .
    The European Commission brought a case (C-61/03 Commission v. United Kingdom) against the UK at the European Court of Justice, for failing to fulfil the Euratom treaty. The case was dismissed on 12 April 2005, the court confirming[1] that the treaty does not apply to uses of nuclear energy for military purposes.[2]

  • Clark

    Thanks for that. Here are some links you could find interesting. Sorenson states that fast-spectrum reactors would be needed to burn up transuranics:
    .
    Part 1: http://www.forbes.com/sites/kirksorensen/2011/07/27/waste-digester/
    Part 2: http://www.forbes.com/sites/kirksorensen/2011/07/29/waste-digester-2/
    .
    Or, if you would rather jump straight to the technical stuff:
    .
    http://www.osti.gov/bridge/servlets/purl/1018987-OjLVsA/1018987.pdf
    .
    I hope you took my point about MSRs being “good” in the spirit it was intended; that a system that makes a pure product is better than one that makes a contaminated product, regardless of the use that the product (U-233 in this case) is then put to.
    .
    Regarding reactors in “odd” places, and that “JASON was one of very few reactors operating within a major population centre”, did you know there was another, also in London?
    .
    http://en.wikipedia.org/wiki/Queen_Mary,_University_of_London#Nuclear_reactor
    .
    Funnily enough, I was doing physics at QMC in 1982, the year the reactor was decommissioned, though I don’t think I ever heard of it and I never visited the Stratford site.
    .
    The “Nuclear Hybrid” looks similar in principle to accelerator driven fission reactors, with a similar problem; the expense of the neutron source. Why would you expect it to blow up? The point of using a separate neutron source is that a well-below critical quantity of fissile material could be used. The problem with fusion has always been the exact opposite of fission. Fission requires the use of multiple cooling and safety systems to prevent positive feedback from catastrophically increasing the rate of reaction, whereas the problem with fusion is keeping the reaction going for more than a fraction of a second.
    .
    So, if reactors aren’t too difficult to hide, and MSRs are “a bomb-makers dream”, shouldn’t we expect that MSR technology has already been developed and that various MSRs are hidden in diverse locations? And what is the answer to your U-233 explosive yield exercise above?

  • Clark

    There’s something a bit odd about the way the “Nuclear Hybrid” is presented:

    “One hybrid would be needed to destroy the waste produced by 10 to 15 LWRs. […] Burning that waste also produces energy.”

    But as I understand it, the whole reason that nuclear waste is such a problem in the first place is that LWRs only extract about 2% of the energy from the fuel, leaving the other 98% to create a radiation hazard for tens of thousands of years.
    .
    So this “burn-up machine” should produce the same power as about 500 or more LWRs. But the article presents the hybrid almost as an accessory to keep LWRs viable. What do you make of this?

  • Derek

    Anon, you clearly have a good understanding on this subject so perhaps you can explain something I do not understand.
    .
    You have explained how anyone with an interest in creating a nuclear weapon could extract Pa233 from an MSR and wait for it to decay to U233.
    .
    However my understanding is that the U233 is necessary to sustain the reaction in an MSR and if it is extracted then the reactor will run out of fuel and stop and would need to have u233 added to get it to start again. ( Or Plutonium 239) Are there sufficient neutrons to create an excess of Pa233 to permit its extraction?

  • Derek

    This including the comments is very relevant to our discussion
    http://energyfromthorium.com/2010/10/02/lftr-discourages-weapons-proliferation/
    .
    In particular the comments from Roger Arnold
    .
    “The response by Drs. Hargrave and Moir strikes me as disingenuous. The flat statement that in a LFTR, “the neutrons that produce U233 also produce 0.13 percent contaminating U232″ has to be misleading, at best. No figure for the percentage of U232 can possibly be given without reference to the particulars of the design to which the figure applies. The actual figure, as I understand it, would be highly dependent on the average intensity of neutron flux in the breeding blanket.
    .
    Kirk (et. al.) have explained that U232 is produced when protactinium (bred from thorium) captures a neutron before it has time to decay to U233. The ratio of U232 to U233 can never be reduced to zero, but it can be made arbitrarily small by making the average neutron flux to which the bred protactinium is exposed arbitrarily small.
    .
    That could theoretically be done by continuous removal of protactinium from the breeding blanket. Kirk has said that that’s at best difficult and maybe infeasible, due to chemical process constraints. But there’s a simpler “brute force” alternative: a “flow through” breeding blanket. Molten ThF4 is exposed to the high neutron flux around the core only briefly, before exiting the breeding blanket and waiting in a holding area long enough for most of the protactinium to decay.
    .
    Nobody says that that would be an economical way to produce weapons-grade U233. The large inventory of thorium required, relative to the production rate of U233, would probably make it prohibitively expensive. The Los Alamos folks evidently concluded as much, when they opted for breeding plutonium from U238 for building bombs. But weapons-grade U233 *could* be produced in that manner.
    .
    The statement that I would rather have seen Hargraves and Moir make is that, in all LFTR designs that make any sense for commercial power production, the U232 contamination levels would be far too high to enable weapons use. And that production of weapons-grade U233 would require a very specialized reactor design that would be uneconomical for power production, and whose intended use for weapons production would be immediately obvious to any knowledgable inspector.
    .
    Those, I believe, are true and defensible statements. The assertion that a LFTR simply *cannot* be used for proliferation of nuclear weapons is not.”
    .
    And
    “I was somewhat hasty in posting my comment above. Hargraves and Moir’s reply to Cameron Reed does start out by saying “A commercial reactor will make just enough uranium to sustain power generation.” So they are talking specifically about a LFTR design that “makes sense for commercial power production”.
    .
    For clarity, it would have been nice if that first sentence had read “Any LFTR for commercial power production would be designed to make just enough uranium ..”. That’s a quibble, but that way it’s clear to hasty readers (like me) that they’re talking about a by-design feature — not something that’s intrinsic to any LFTR.
    .
    I think my comment about the percentage of U232 in the bred uranium is still valid. I.e., that it depends on the average neutron flux in the breeding blanket, and that a “flow through” breeding blanket could, in principle, be used for production of “weapons-grade” U233. The points, however, are that (a) it wouldn’t be a licensed commercial design in that case, and (b) if a rogue outfit with the technical resources were really set on acquiring nuclear weapons, a military-style plutonium breeder is a very much easier and more economical way to go.”
    .
    And the comment by David LeBanc
    “Just to clarify a point. U232 production is not from Pa233 before it decays to U233. The two prime ways it is produced is from n,2n reactions on Th232 which gives Pa231 which can absorb a neutron and then quickly decay to U232. The other is by n,2n reactions in U233 itself. n,2n means one neutron in, two comes out. Thus how quickly you would move ThF4 through a blanket doesn’t have much of an effect on the ratio of U232/U233. The value of 0.13 percent U232 is of course variable as Roger mentions but a pretty wide variation of designs does stay pretty close to this value. U232 doesn’t make it impossible to make a weapon but certainly makes it far more difficult and much easier to detect any illicit use (the hard gamma ray is very penetrating and is like a fingerprint that tells anyone, look, U233 over here!).
    .
    The main proliferation resistance of LFTR is from the very enhanced physical protection (always within a 700 C hotcell) and the fact that you can dump in U238F4 at any time to make all the uranium useless for weapons. If somehow that isn’t enough, one can also look at running the cycle denatured (always including enough U238), especially in Single Fluid designs.”
    .
    .
    To summarise the conclusions from this source :-
    .
    Any ‘commercial’ MSR reactor would be designed to NOT produce weapons grade U233
    .
    Any government entity could modify an MSR or build their own MSR that COULD create U233.
    .
    Therefore NPT inspections would be necessary to ensure this does not happen JUST LIKE happens with existing reactors.
    .
    The problem of course is with those nations who are not signatories to the NPT (Israel, Pakistan, India, North Korea). Those nations already have nuclear weapons created from conventional reactors so they do not need the existence of MSR technology to get nukes.

  • Clark

    Derek, thanks for finding that discussion. Something I find frustrating about the blog format is that though it produces good in-depth discussions, it can be difficult to find just the discussion you’re looking for, so thanks for hunting that out. I also edited your comments to add placeholders to maintain the paragraph breaks; the blog software has a very annoying “feature” that removes blank lines; use a dot to enforce paragraph breaks.
    .
    I think that the ability of MSRs to burn up transuranics has been overstated. Using a few kilos of plutonium to start each MSR would take forever to significantly reduce the current stockpile of tonnes. I think Sorenson is somewhat guilty of this too, but conversely, he does write articles accessible to reasonably technical non-specialists; he does seem to have a commitment to honest education, though of course he has his own commercial venture to promote.
    .
    In the thread Derek discovered I found this link regarding the commercial failure of a project similar to the Desertec solar concentrator:
    .
    http://www.bizjournals.com/phoenix/morning_call/2010/09/plug_pulled_on_solar_plant.html
    .
    Disappointing, but I don’t regard it as fatal to the concept. Nuclear power has enjoyed huge de-facto subsidies which, if applied to solar thermal concentration, could well kick-start it into viability.
    .
    The proliferation issue seems to be part of a larger, more general problem; advancement in technology in general increases the potential destructive capabilities of any party that wishes to abuse civil technology. An obvious example is the use of commercial aircraft as weapons on 9/11. A less well known example is the growing availability of biotechnology. A recent Radio 4 programme explored the world of “kitchen experimenters”, who could soon be able to manufacture lethal biological viruses at home using mail-order DNA fragments, stitched together using cheap home-made equipment.

  • Clark

    Another quote from the energyfromthorium thread which echoes thoughts of my own:

    The obvious proliferation risk is the groundswell of new U-235 enrichment plants. Many nations are planning this, claiming the need for energy supply security, yet possibly hiding their desire to obtain nuclear arms. Argentina is restarting its enrichment plant. Saudi Arabia, Jordan, South Korea, and Vietnam all announced plans to build them.
    .
    Making LFTRs available worldwide will eliminate the excuse that such nations require uranium enrichment plants for energy supply security. [My emphasis]

  • Derek

    On the subject of solar power I just got back from a trip to Australia which included a trip through the Northern Territories where I saw the Concentrated Photo-Voltaic solar array at Hermannsburg.
    http://carolailles.photodeck.com/media/b600c61a-0185-11e0-9aa5-2da04d218e71-hermannsburg-solar-power-station
    .
    http://en.wikipedia.org/wiki/Concentrated_photovoltaics
    .
    This array has now been switched off because of the the problems of:-
    It could not supply total peak power needs of the community so standby diesel generators were required.
    .
    Starting and stopping the diesel generators frequently led to increased maintenance costs.
    .
    Dust on the mirrors reduced PV output significantly.
    .
    They simply cost too much to build and maintain.

  • Clark

    Derek, my view is that power generation has become a war, and the first casualty is truthfulness. There is the obvious battle between nuclear and anti-nuclear. Then there are the established players trying to preserve their territory. We can be tempted to lump solar, wind power, tidal, etc. all together into an imagined “Green” bloc, but implementation requires industry with all its commercial pressures, and I bet that, for instance, wind turbine manufacturers are attempting to discredit solar and vice-versa, etc., etc., etc.
    .
    We have many parties attempting to bend the truth, and in particular the nuke vs. Green-anti-nuke argument has become very polarised. Our first responsibility is to keep our thinking balanced; it is too easy to take sides in this atmosphere, and after that our own arguments are likely to become skewed in our chosen direction.
    .
    I see two causes for this. (1) Diversification of energy production has been left much too late, and now the crisis is upon us. (2) Fossil fuels were effectively a windfall, a gift from the past, which has led humanity to become addicted to a very cheap energy supply. Any new energy source is likely to prove more expensive than what we’re used to, though the cost will probably fall as production becomes routine.
    .
    The photovoltaic concentration approach has the drawback of producing electricity directly, and our electrical energy storage system are inadequate. Thermal concentration should have an advantage by storing heat in, coincidentally, molten salt.
    .
    Humanity is not in a good position to decide which technologies will work best, because development has been left too late. Our best Plan B would seem to be to invest the resources to develop many diverse generation methods, so that failure of a proportion of methods wouldn’t be too bad.

  • Anon

    Clark,

    On the waste burning issue, I don’t have anything to add really. Plenty claims but usually a distinct lack of actual fuel burn simulations. Apparently the Bill Gates supported Travelling Wave Reactor (also claimed as a waste burner) people, TerraPower, spent a lot of money on simulations which they they never released because they didn’t substantiate their claims. So they are back to the drawing board.
    .
    I haven’t paid that much attention to waste burning (other than traditional spent fuel reprocessing) because there is nothing firm to actually study yet. I probably should dig into it a bit more.

    Derek,
    .
    Yes, if reactors are 100% supervised then you can’t divert anything without being seen (assuming the “supervisors” want to see). But we really need to see what the true fuel cycle is in any large scale practical design, to begin to comment on any glaring weaknesses or not.
    .
    In terms of safety as well, certain passive safety features may work well on a small scale test reactor but how well do they scale up? How does passive cooling work if, for some reason, your heat-synch (the reactor building etc) is no longer there?
    .
    By the time pure U-233 became available, the US was about 15 years into it the bomb programme with U-235, Pu-239 and the Hydrogen Bomb. There was no size of bang they couldn’t make with these.
    .
    U-233 has about one quarter the bare sphere critical mass of U-235. As the US and UK proved with SOB and Orange Herald, if you use an implosion type bomb with a low spontaneous fission isotope, then you can squeeze a lot of effective critical masses together in the space of time you have. It would seem you can squeeze more U-233 effective critical masses (and the effective critical mass is inversely proportional to the square of the density). Without doing any calculations, there seems no reason to assume you can’t get over one megaton based on what was achieved with U-235. Probably best left there.
    .
    Please don’t get the impression I am any sort of real expert on this by the way!

  • Anon

    “your heat-synch (the reactor building etc) is no longer there?”

    Err “Heat Sink” of course!

  • Clark

    Is there anything preventing the anti-nuke lobby from running their own fuel-burn simulations, to show that such things can’t work? This would be a good way to open up debate.

    “Apparently the Bill Gates supported Travelling Wave Reactor (also claimed as a waste burner) people, TerraPower, spent a lot of money on simulations which they they never released because they didn’t substantiate their claims.”

    Ah, good old Bill Gates, always was keen on Non-Disclosure Agreements! This issue also severely disadvantages developers of Free Software such as Linux and GNU. NDAs are why GNU/Linux systems sometimes can’t support newer hardware; Micro$oft pressure hardware manufacturers to disclose hardware interface specifications only to Microsoft. I think NDAs are utterly contrart to the spirit of science. Results should be published, even (especially?) if the funders don’t like them.

  • Clark

    Some things I’d like to know about MSR behaviour in accident and disaster conditions: (1) Tsunami / flood – what happens if containment fails and dumps the molten fuel salt into an excess of water? (2) What happens if the molten salt begins to boil?

  • Komodo

    Most of the actinide fluorides are claimed to be insoluble or poorly soluble in water. However, liquid salt reactors don’t just contain these. The majority of the circulating salt is a carrier; I’ve seen lithium and/or beryllium fluoride cited. The former is sparingly soluble, and by analogy with sodium fluoride rat poison, I would not expect it to do the local wildlife much good. Beryllium salts are all highly toxic, and the fluoride is freely soluble in water. Filthy as beryllium is, fluoride makes it even nastier:
    http://www.fluoridealert.org/health/respiratory/beryllium.html
    .
    The radioactive material left behind, if insoluble, would be very finely divided, and could wind up as intensely dangerous concentrates due to tidal action (see “placer deposit”).
    .
    Thorium fluoride would boil at about the same temperature as the carrier, I gather, the other fluorides have higher b.p’s.

  • Komodo

    Too much detail on LiF/BeF2 molten salt mix here:
    aries.ucsd.edu/raffray/publications/FST/TOFE_15_Zaghloul.pdf
    .
    “…good tritium breeding potential…” *Ulp*
    .
    I can see major powers taking a keen interest in that one.
    .
    You did physics, Clark -you do the maths! It’s all rather over an earth scientist’s head.
    .
    Big .pdf. If your connection’s slow, have a coffee.

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