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    1. @Jack Devanney

      Based on my conversation with Dr. Lyons at the Advanced Reactor Technical Summit and the comments that he made during Q&A, I’m positive that he agrees with your statement. He recognizes that there are numerous reactor concepts that can make good use of the fissile material in a form that is not MOX in pellets that are aimed to replace those used in conventional light water reactors.

      He includes molten salt in reactors like ThorCon’s and Terrestrial Energy’s in the potential universe of better uses for the inherently useful and potentially valuable material.

    2. Jack Devanney, I read the PDF on WG Pu — with delight — for instance in the phrase “no sentient bombmaker” !
      I did not know that U-233 production can produce the remarkably valuable Pu-238, although I’m not sure if it can be used to supply NASA.
      I still grieve that the ESA’s gallant robotic emissaries to a comet, Rosetta and Philae, lacked an RTG and the solar panels upon which Philae depended, so sadly ended up in the shade.

      1. The Pu-238 is mixed with all the other Pu isotopes, which makes it worthless for RTGs, for the same reason that the remaining Pu-239 is worthless for weapons.

        Pu-238 for RTGs is always produced by extraction Neptunium from spent fuel, which is isotopically pure (Np237). This is than put back into the reactor to produce pure Pu-239. Isotope separation, already difficult for Uranium, has never been attempted for Pu.

  1. “Back in the 1950s, we built several fast reactors and demonstrated their impressive safety attributes, including proving that they could not melt down even with a complete loss of coolant.”

    It should be loss of power (or pumps), not coolant. Gas cooled reactors are the only type of solid-fuel reactors which can be safe with loss of coolant. In a liquid-fuel reactor loss of coolant-fuel is not a safety concern, but a safety feature. Liquid-coolant-fuel can be drained out of the reactor into a drain tank. I hope USA will design a liquid-fuel fast reactor (MSFR) and maintain technological superiority over other nations which have spent billions over obsolete solid-fuel fast reactors.

    1. I agree. I also found the statement weird.
      However, I’m not sure if a MSFR is the way to go, as Russians seem to be quite confident of their sodium and lead reactors.

    1. Indeed, GE-Hitachi also has a MOU in place with Southern Nuclear to “collaborate on the development and licensing of fast reactors including GEH’s Prism” which “sees the companies agreeing to work together in future US Department of Energy advanced reactor licensing programs…”

      Of course, the time that saw this was October 2016; since then Southern Nuclear has acquired a more pressing issue. But one might imagine “$ufficient interest” from DOE might yes induce the collaboration to actively collaborate.

      Doesn’t mean Thorcon and/or Terrestrial Energy might not be better placed to capitalize on it.

  2. Dilute and dispose would be a wasteful crime.

    Burning the plutonium in thermal reactors is better, but it’s a bit of a waste too. In my opinion the material has a lot of value.

    I don’t see why we can’t just sit on this material until we need it in the future. Like others said, it can be used for seed material in breeders.

    I heard through hearsay that the MOX fraction in a LWR is kept to no more than 30% for reasons I’m a bit foggy about. It probably has to do with the lower Beff, and flux discontinuities making peaking difficult to manage. Flux at 6 kilowatts per foot in a plutonium rod is significantly lower than flux at 6 kilowatts per foot in a uranium rod.

    If we were to take this 34 tons of plutonium and make MOX fuel assemblies with it, I calculate that we would have approximately 21 reloads of a 4 loop Westinghouse.

    4 loop Westinghouse core has 90 tons of heavy metal, and loads about 76 out of 193 fuel assemblies every 18 months. The 76 reload assemblies have about 35 tons heavy metal. You could blend this 34 tons of plutonium into about 756 tons with an effective enrichment of 4.5%, which would support about 21 reloads. So the construction of the MOX facility for this 34 tons of plutonium and it’s billions of dollars budget is for 21 reloads. A reload costs about $100E6. 21 reloads would have a market value a little over $2E9.

    1. Correction: each MOX reload might only cost $65M vs. $100M because there wouldn’t be enrichment (SWU) costs because the material was refined decades ago. So, the 21 reloads of MOX COULD be cheaper than standard reloads and would have a market value of maybe $1.5B. Still, not worth very much on the market compared to the money spent thus far.

  3. This article betrays its purpose. While arguing for the advanced concepts, it reinforces the false belief that “plutonium = danger”. Plutonium is a valuable resource, maybe the most valuable resource for the next few centuries. The public should be educated about its benefits and potential, not scared with phantom menaces.

    And the Russians are still burning plutonium in the fast reactors. It just comes from the storage area B “reactor-grade Pu” and not storage area A “weapons-grage Pu” of the same facility. It’s actually harder to fabricate MOX fuel with reactor-grade Pu, since it’s more active, but the experience and expertise obtained are more valuable. The lack of such expertise in the US is what should scare the public.

    1. You need to bear in mind the distinction between plutonium & weapons grade plutonium.
      If the plutonium is nearly pure Pu239 it is usable for weapons & can reasonably be considered dangerous. Putting weapons grade plutonium in a power reactor turns Pu239 into either fission products or Pu240 which makes the plutonium not useable for weapons.

  4. Syndroma says -“Plutonium is a valuable resource,”

    What a weird world. It’s like destroying thousands of gallons of clean burning crude instead of refining it. Future generations will look back at these times and just shake their heads in disbelief.

  5. Mixing the plutonium with thorium for utilization in the latest CANDU reactors would seem to be the simplest near term solution. Even the existence of– just one– such plutonium/thorium reactor in the US might end the legal moratorium on building new fission reactors in some states such as California. The TVA should have done this yesterday, IMO:-)

    The long term solution, IMO, is the use of plutonium in small plutonium/thorium light water reactors or Liquid Fluoride Thorium reactors for remotely sited ocean nuclear reactors for the production of carbon neutral methanol, gasoline, jet fuel, nitrogenous fertilizers and other major industrial chemicals.


  6. Has anyone looked at mixing the weapons plutonium with thorium & putting that through a reactor to make the plutonium unusable for weapon & breed U233 to jump start the thorium fuel cycle?

    1. This article adresses your question although it could use some editing. nuclearpowerdaily.com/reports/Thorium_reactors_may_dispose_of_enormous_amounts_of_weapons_grade_plutonium_999.html

      1. It looks like the URL didn’t come out correctly.


      2. Rats! Still having trouble getting the long url.

        A search, “Thorium reactors may dispose enormous amounts weapons grade plutonium” will lead to a number of sites.

  7. So far as using plutonium with thorium is concerned, the Europeans studied this circa 1970 in the context of high-temperature gas-ccoled fuel. This approach appeared particularly attractive because of the large neutron-capture cross-section of thorium as compared to uranium-238. The limited results reported were quite good, although it must be emphasized that this was with the British “tubular interacting fuel pin” concept, originally designed for using low-enriched uranium in HTGRs, which gives a much better thermalized neutron spectrum than either the pebble-bed or the General Atomics type fuel.

  8. So far the efforts to prevent countries that want to develop a nuclear bomb from acquiring plutonium. have been successfull. When India developed a plutonium bomb Pakistan wanted to import plutonium very badly. They had to satisfy themselves with developing a uranium bomb using centrifuges for enrichment of uranium.The technology for these centrifuges was transmitted from Holland by a Pakistani who lived in Holland. The ability of countries which used reprocessing: France, United Kingdom, Russia and Hanford in the USA is one of the greatest security success stories..If there is any doubt that this will continue to be the case we could bury it in a geological repository., for example, Yucca Mountain. Representative John Shimkus (R. ILL) has introduced a bill to move forward on Yucca Mountain. Previously, Democratic members of Congress have opposed development of Yucca Mountain while Republican memebers of Congress have moved the ball a little bit.

  9. Plutonium is dramatically LESS proliferative than the U235 found in nature, contra the disinformational hype.

    Lyons is a technological genius but he doesn’t help the political case with statements like: “If even a tiny fraction of this material [pu239] fell into terrorists’ hands, they could threaten nuclear terrorism around the world.”

    Pu239 bombs require the resources of a nation; even as stolen shaped weapons the implosion mechanism is well beyond skills of typical troglodyte-terrorists. In order to fashion 10k critical masses out of 34 tons of pu239 would require highly advanced tamping & neutron reflectors.

  10. It is difficult to separate U 235 from U-238. High power centrifuges are used. Pu-239 is relatively easy to separate from U-238. Susanne E. Vandenbosch

    1. Susanne

      I wouldn’t classify centrifuges as “high power” devices,

      One of the most impressive energy efficiency projects I ever witnessed was Georges Besse II. That centrifuge-based enrichment facility nearly completely replaced the capacity of Georges Besse I, gaseous diffusion plant that consumed 2700 Mme when operating at full capacity. The centrifuges consumed about 5% as much energy, something on the order of 50 MWe.

      Centrifuges are sophisticated. The technology used is carefully controlled, but can be replicated with substantial effort, often involving years worth of trial and error.

      1. I agree. High power centrifuges is a poor choice of words. Sophisticated centrifuges is a much better choice. Susanne E. Vandenbosch

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