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  1. “That material should be held in reserve as starter material for a rapidly growing advanced nuclear reactor industry.”

    Rod….I agree with you, if in fact there is “a rapidly growing advanced nuclear reactor industry”. But, (perhaps mistakingly), my impression from attending your blog is that this pursuit of advanced nuclear reactors is more an R&D effort than it is an actual ongoing marketing and distributing success? Yes, there is an NE industry, but can it really he said that advanced nuclear reactors, at this time, are enjoying rapidly growing deployment by that industry?

    1. @poa

      I wasn’t claiming that there IS a rapidly growing advanced nuclear reactor industry. There are a number of factors that must be addressed to enable that beneficial situation to become a reality.

      An accessible stockpile of properly enriched fuel at a predictable price is one of those factors.

      Proper pricing and delivery schedules for the completed system — which is dependent on price & availability of both major and minor components — is a requirement for any successful marketing effort.

      1. Well, the direct quote I provided seems to address the eventuality in the present tense. Not nit picking, because its an important distinction. You are advocating that the DOE base decisions regarding uranium stockpiles on predictions about the possible turn-around of an industry that is seemingly falling from favor. Personally I hope you are right. But your optimism about the future of NE doesn’t seem to be shared by our legislature, or the regulatory agencies determining that future.

        1. @poa

          Sure, it was a direct quote, but it was also pulled out of context. It is difficult for me to see how any reader would believe that I am asserting that the advanced reactor industry is already growing rapidly.

          Please reread my piece. I am advocating the action for at least two reasons. One is to prevent the government from making a bad market worse by adding supply at a time when it is not needed.

          The second action is admittedly focused on enabling and important technology to flourish. It pains me to recognize that some people don’t agree that it should flourish, but that will never slow or stop my advocacy for government actions that allow it to move forward with a reduced amount of friction.

          Besides, if I am wrong, the 19.75% enriched stockpile can be blended down to LEU at a later date. It is not an irreversible step, like blending it down to 3-5%.

      2. Rod The best suggestion is NOT to downblend. A stalemate that does nothing, except securely maintain present stockpiles (which the military knows how to do), has the best chance of succeeding in the existing political climate, and is the BEST outcome for any new reactor development. Why add U-238 to any stockpile rich in Pu-235, or for that matter, U-233 or Pu-239? Undoing what it cost taxpayer many billions of dollars to do is stupid and wasteful. Give reactor designers freedom to what kind of fuel they would like to access for their prototypes, rather than choose a particular blend mxiture and limit the kind of test reactors that can be built? There other methods of preventing weapons proliferation than to downblend separated fissiles with U-238.

        1. @FShu

          In an ideal world, I’d fully agree with you. It’s difficult to say this without getting shouted down in most places, but I like HEU and Pu as reactor fuels. Not for all reactors, mind you, but for the small to tiny reactors that I would eventually like to design and market, it’s best not to add materials that only poison reaction and require larger machines.

          It would be good to keep a major portion of the stockpile in its current form, but it shouldn’t be harmful to anyone (other than competitors) to take the somewhat time consuming step of blending to 19.75% now, in parallel with many other critical path items for certain designs that are already well underway. If pressed, I can name at least four and probably more projects that have already selected that enrichment level as the best available choice for their systems under current constraints of international rules.

          Using anything other than LEU will limit markets and make international sales a painful process.

          1. Rod I’m arguing the case not for idealistic reasons but practical ones. Agreeing to downblending as the norm is harmful not only to the small, compact kind of reactors that power naval submarines and other vessels, but to the dream of thorium breeders that get away from the idea of using plutonium as a fuel. Yes, it’s possible to produce U-233 with 19.75% LEU, but people will use the precedent to argue that you need to add enough U-238 (in natural or depleted uranium) to the blanket so that any separated U-233 satisfies the 19.75% LEU rule. Agreeing to this restriction takes us off the high road and puts us in the same ethical position as those who argue for burning natural gas as being only half as bad as coal.

  2. This idea would be great for ThorCon. Here is a footnote from the ThorCon Executive Summary:

    Footnote 38 This [20% enrichment] will require an expansion in enrichment capability. But if the demand is there so will the supply. Urenco has indicated they can have a 20% LEU enrichment plant operating four years after the decision to make the investment is made.

    I infer that ThorCon will use 5% uranium to prove its concept and for its first installs while waiting for Urenco to produce 20% uranium. Four years is a long time to wait when your idea would allow 20% uranium to be used in the prototype.

    Since Terrestrial Energy’s design (truck/train delivery) is similar to ThorCon’s Design (barge delivery), Terrestrial would also be a candidate to use the 20% uranium. Terrestrial is applying for a DOE loan guarantee.

    What ever happened to the U233 the government was going to down blend?

    1. Molten salt reactors can run on the same enrichment
      as a PWR. The problem is the make up fuel. MSR’s
      can add fuel on the fly. This is a fantastic advantage.
      No excess reactivity. No wasteful burnable poisons.
      Very long and high burnup.

      But we need to stay near the eutectic. So the makeup
      fuel has to have the same heavy metal content
      as the fuel in the primary loop. But unless the fissile
      content of the makeup fuel is a lot higher than
      the fissile content of the fuel that is already in the loop
      you are chasing your tail since you are pushing out
      about as much fissile as you are adding. 4 to 5%
      enrichment in the primary loop and 15 to 20 pct
      in the make up fuel works fine.

  3. Another potential useful application of Uranium enriched to near 20% is medical isotope production, specifically Mo99/Tc99m production. Several of the concepts currently approved (e.g., Shine) or seeking approval (e.g., Northwest Medical Isotopes) have improved process yields with higher Uranium enrichment (so using the highest legally available Uranium enrichment level is optimal).

    This may be outrageous to some, but perhaps this might be a good time to start rethinking the current LEU/HEU mentality to allow the use of higher levels of Uranium enrichment.

    1. Using HEU targets is absolutely the best way to make a broad spectrum of medically (and other) useful isotopes. All other methods, LEU targets, accelerator-based systems, can’t hold a candle to the production percentages for HEU targets. I have often thought that HEU has gotten a bad rap both in the nuclear business and the public perception. I guess it was born of the proliferation paranoia of the 1970s. I had to deal with the consequences of it when changing a research reactor core from HEU aluminide fuel to LEU dispersion. It worked okay for that particular application, but took a lot of time and effort for, you guessed it, licensing.

  4. How about blending the HEU with thorium & putting that through existing light & heavy water reactors.

    That would result in used fuel rods with fission products, thorium & uranium with a mix of isotopes of U235, U233 &enough U232 to make it unsuitable for bomb making, but fine for various reactors.

  5. Downblending should be done with U-232, in a LFTR. Any action should wait on the laws being fixed, because technically U-233 in this case would still be HEU, and it is absurd to consider fuel salt from a LFTR to be a diversion risk. The core of a LFTR is about the safest place on earth for such material, and shortly after reactor startup, it is absolutely worthless for weapons.

    Instead of defining an arbitrary LEU/HEU boundary, legislation should be focused on the safe use of this highly valuable resource. Perhaps the distinction made sense when enriched uranium was sold to manufacturers for solid fuel assemblies, but no longer for fluid fuels. It will be trivial to supervise the loading of UF4 into a LFTR, and then it can burn thorium indefinitely. Once the thorium fuel cycle is established it will ultimately eliminate the need for enrichment at all, which would be the best result.

    Even downblending to the highest legal limit is a waste for LEU burners. U-235 is inherently “downblended” after being added to the salt, and adding superfluous U-238 only makes the whole fuel cycle significantly less efficient. For a single-fluid LEU-burning MSR, fuel can’t be shuffled as in solid-fueled reactors, and it may ultimately require more separative work than even conventional reactors. It isn’t clear that this path makes sense at all, and either way, it only pushes the problem down the road. At some point “spent” MSR fuel will need to be re-enriched or burned down in a fast reactor.

  6. I’d like to see more thought and attention paid towards making use of the depleted Uranium and Thorium stockpiles of fertile potential nuclear fuel. Using ever-increasing amounts of fissile U-235 surely reduces the capacity of turning all those fertile stockpiles into fissile material. Yes that means more attention must be paid to breeder reactor technology but in the long run they will be needed to ensure efficiency and, of no small concern, reduction of nuclear waste.

  7. Is elimination of the weapons grade stockpile a condition of the treaty with Russia ? Also, what’s happening with the proposed downblending of Pu 239 to MOX ? That would be almost as handy for advanced reactors, and probably cost the US taxpayer as much as the uranium did.

    1. John,

      When I worked more than 10 years agon on a project for DOE related to MOX but not directly involved, it was my understanding that by treaty, the US was to dispose 34 MT of surplus Pu via MOX or some other manner. For example, there were several MTs of Pu-bearing material that could not be processed by the MOX plant (at least back then). DOE’s proposed solution: store part and place more Pu material into WIPP. Not sure what the ultimate decision that DOE made about this material.

      I found a supplemental EIS by DOE about the current plans. See: http://fissilematerials.org/library/doe15.pdf

      The crux of the matter is that MOX is part of the treaty with Russia. If we don’t complete the MOX program then we may need to renegotiate the treaty. Russia, I believe, are starting to burn-up their excess Pu in their SMR fast reactor that just started operations.


  8. Here’s what I sent in….

    September 17, 2016
    Office of Nuclear Energy
    US Department of Energy

    Re: RFI on Uranium Transfers – Downgrade to HEU20

    You requested information on the market impact of selling surplus weapons-grade uranium (HEU), downgraded to ~4% U-235 content (LEU4), to be sold as fuel for solid fuel light water nuclear power plants.

    Instead, I recommend a better use, downgrading the uranium to 19.75% U-235 (LEU20) and storing it for sale to companies developing advanced nuclear reactors that require this level of enriched uranium.

    Such LEU20 is not weapons usable, so this downgrading would satisfy the goal of removing the risk of loss of HEU to weapons-intent terrorists or hostile nations.

    LEU20 is important for make-up fuel in molten salt reactors; using LEU4 dilutes the fuel salt too much, leading to short fuel cycles.

    LEU20 is also important for research reactors and medical isotope production reactors. Making a supply of HEU20 available will encourage institutions like MIT to convert HEU-fueled reactors to ones without weapons-usable uranium.

    LEU20 is not available in quantity in the US today. US companies that might purchase LEU20 from the government include Martingale (Florida), Elysium (Massachusetts), Transatomic Power (Massachusetts), and Terrestrial Energy (New York and Canada).

    Nations such as Indonesia, which is considering installing molten salt reactors, could purchase LEU20 from the US rather than from Russia.

    Should customers not buy stored LEU20 after 10 years, the proposed plan to downgrade to LEU4 could still be carried out.

    In summary, I recommend DOE downgrade surplus HEU to LEU20, store it, and sell it to organizations developing advanced nuclear power reactors.

    Robert F. Hargraves
    7 Cuttings Corner
    Hanover NH 03755
    Author: THORIUM: energy cheaper than coal
    Founder: ThorCon International

  9. A key question is how much of the down blended HEU should be held in reserve for U.S. advanced nuclear developers. I think the absolute minimum is that 20 metric tons of HEU should be down blended and held in reserve. Much better is at least 40 to 60 metric tons. The analysis follows:

    The basic question is how much it would cost Urenco to amend the license and modify their $1.5 billion, 4,600,000 SWU/yr enrichment plant in New Mexico to produce uranium enriched up to 19.75%. At $140/SWU, this plant produces annual revenues of about $644 million. (I’m using Urenco’s New Mexico facility as the example, but it could be any western enrichment vendor).

    We can probably bound this cost as being somewhere between 2% to 20% of the original construction cost (e.g., between $30 million and $300 million).

    Say that we want the extra cost for >5% SWU to be a 5% premium, that is, a premium of 0.05($140/SWU) = $7/SWU.

    Then Urenco would need to have assured SWU orders of ($30 million)/($7/SWU) = 4.3 million SWU to ($300 million)/($7/SWU) = 43 million SWU.

    For advanced nuclear reactor developers to sell enough reactors (with start-up fuel) so that Urenco could be assured (get procurement contracts) of 4.3 to 43. million SWU, to first order the amount of 19.75% enriched uranium that DOE should reserve should contain a similar number of SWU (4.3 to 43. million SWU).

    Once this much SWU has been used in producing fuel for new advanced reactors, there should be enough new customers willing to enter into procurement contracts with Urenco that they can get a good deal (premium of 5 to 10% over <5% enrichment SWU cost).

    It takes 45 SWU/kg to produce 19.75% enriched uranium (tails assay of 0.20%, Fig. “Uranium Enrichment and Uses),


    This suggests that we want to reserve somewhere between (4.3 million SWU)/(45,000 SWU/t) = 100 metric tons to (43. million SWU)/(45,000 SWU/t) = 1000 metric tons of 19.75% enriched uranium.

    In this case, we need to reserve somewhere between 20 and 200 metric tons of HEU to produce 19.75% enriched uranium. This is my basis for saying that 20 metric tons of surplus HEU is the absolute minimum, and 40 to 60 metric tons is a better target.

  10. To show how “in sync” Gov. Cuomo is with these motions to redeem nuclear in New York, yesterday there was a trivial oil spill in a small canal at Indian Point. NOTHING to do with reactor. Cuomo goes on the air — just heard him once again on WCBS-Radio — stating “there isn’t a night that passes when I think of our children and GOD FORBID if anything happened at Indian Point.” Exact words. That kind of painfully repeated statement sets back nuclear’s (unchallenging) PR struggle and image by how many years?…

    James Greenidge
    Queens NY

    1. Well, its only set back as far as NE’s PR efforts to counter such BS. And, my bet is the industry will do NOTHING to counter it through effective PR efforts. I am beginning to see the NE industry and its advocates as a compilation of adherents who snivel and whine, behind the scenes, about being bullied by the government, competing energy interests, and media entities, but do nothing to defend themselves out in the open. Such misrepresentations, such as Cuomo offered, stick in the public’s mind like glue, unless countered immediately with FUD busting facts. Where are the FUD busting facts aired? On blogs such as this one, which is read by the choir. I’m not belittling Rod’s efforts. They are commendable and honorable. But they are not enough. Nor do the occassional protests, waged by the workers and families of those reliant upon the industry, reach enough of our populace to turn the tables in NE’s favor. Absent an engaged, ever present, and loud PR campaign, people like Cuomo will continue, unchallenged, to shape the public’s perception of nuclear energy.

      1. “Absent an engaged, ever present, and loud PR campaign, people like “Cuomo will continue, unchallenged, to shape the public’s perception of nuclear energy.”

        Here is a different question. These anti nuclear people are not dumb. They know the safety record. They know they are close to destroying a safe reliable source of electricity. Many of these folks are politicians. How do they benefit from needlessly frightening people?

        1. Needlessly??? By whose account? Frightening the people is a tool for developing policy and pursuing an agenda. Look at our invasion of Iraq. Trump’s success at campaigning. Those that benefit from the fear would argue with you about the “needless” premise you offer. Governance by “BOO!!!” is the rule of the day. And, by the way, why are you reading this instead of cowering under your bed? If those nasty Muslim terrists don’t getcha, Indian Point’s radiation will.

          1. It’s not all doom and gloom, at least for New York State and vicinity, as explained in the following article:


            Politicians in NYS have finally come to their senses and modified the state’s “Clean Energy Standard” to include nuclear power with respect to electricity generation. This is designed to “save” several upstate plants and, by default, Indian Point as well. This is very good news. By including nuclear electricity, the state has already achieved its 2030 goal of generating 50% of the state’s electricity with clean sources (it’s now 56%). I’m assuming the politicians will increase that goal to something like 75% sometime in the near future; otherwise we look sort of silly. I hope that Cuomo will take the lead here and that the NG/Coal lobby will not get in the way since it is their energy sector that will have to be reduced (coal is only 2%)

            And, by the way, cowering under one’s bed will reduce your negligible, unmeasurable radiation exposure from IP by a yet smaller, unmeasurable amount. It will, however, reduce the small radiation exposure from your sleeping partner (assuming you have one), by a small, but measurable amount.

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