Similar Posts

Recent Comments from our Readers

  1. Avatar
  2. Avatar
  3. Avatar
  4. Avatar
  5. Avatar

Leave a Reply

Your email address will not be published. Required fields are marked *

Subscribe to Comments:

23 Comments

  1. It’s interesting to contrast the serious troubles that the MOX project is having with the spectacular success that the BLEU (Blended Low Enriched Uranium) project has enjoyed. Here are two projects that produce nuclear fuel from weapons material, but one goes forward without a hitch, almost unseen and unknown, and the other turns into a quagmire.

    Now I realize that dealing with uranium-plutonium fuel is more technically challenging than dealing with fuel that is just uranium, but the French tackled most of the technical challenges of MOX ages ago.

    It only makes sense when you consider that the effect of one program was to displace (atrophy?) domestic uranium fuel production for a nontrivial amount of time, while the effect of the other is to set up a new plutonium economy. Hmm …

    [Note: Although I have never worked on MOX personally, I do work for the company that is building the MOX facility in South Carolina]

    1. Free the U-238!

      Seriously, if this is so hard why can’t we just gift it to teh Rooskies and pay ’em to make it into BN800 fuel? Dross into gold! 🙂

      [/irony]

  2. In commercial reactors, Plutonium is produced by U238 + n absorption. U B- decays to Np, which B- decays to Pu. A typical reactor gets 40% of its late core cycle power from Pu fission.
    BWRs can exploit this phenomenon by operating at high rod lines early in the core cycle. This lowers the boiling boundary (Z axis), which hardens the neutron flux at upper core elevations. The higher energy spectrum neutron flux enhances Pu production, which is ultimately utilized during late cycle coast down. The reactor will coast down slower, and at the same time, display the increased sensitivity to reactivity addition associated with Pu smaller Delayed Neutron Fraction (B effective). The high rod lines also save recirc pumping power early in life, the net result is substantially more power production from the same initial fuel load. EOC RPT (end of cycle recirc pump trip) actuation is installed for this consideration.
    The take away is – we already use Plutonium every day in nuclear power plants. The US government has always opposed civilian use of seperated Plutonium. It has been considered proliferative by definition.

  3. One alternative course of action is to use ThorCon, a molten salt reactor design nearing completion, for first use in Indonesia.

    * ThorCon can burn or downgrade the 34 tons of excess weapons grade plutonium in the US inventory, required by our treaty with Russia.

    * To do this, ThorCon requires far less fuel preparation than a solid fuel reactor.

    * If the nation wills it, ThorCon can begin burning this plutonium in five years.

    * The plutonium will produce 2 GW of pollution-free, dispatchable power for 24 years. If this power replaces coal, 300 million tons less CO2 will be spewed into our childrens’ atmosphere.

    * The process will also produce 12,000 kg of fissile in the form of 233U, which can be down- blended to commercial reactor fuel. If burned in ThorCon’s, this 233U will produce 19 GW-y of electricity. If this power replaces coal, an additional 120 million tons less CO2 will be discharged into the troposphere.

    * The resulting waste, occupying 225 m3 of dry cask storage, will be useless as weapons material, even for a low yield fizzle bomb.

    This can be carried out in a virtually unmodified ThorCon power plant. The technology is described here.
    http://thorconpower.com/docs/wgpu.pdf

    We are not pursuing this path, but the government could. We are intent on mass-producing modular power plants delivering electricity cheaper than coal, Powering Up Our World.

    1. Oh dear … not another one of these gee-whiz reactor designs that can be ready to go “in five years.”

      I’m afraid that you’ll have to get at the back of the line.

        1. And there are a lot of talented people who have been in the game a lot longer who have been promising a spiffy new reactor to solve all our problems that will be ready to go “in five years” for a long time now.

          It was a lot easier to swallow these claims back when the economy was humming along, natural gas was still expensive, and there was demand for new power generation. These days, however, …

          1. Brian is of course correct. We have not delivered, nor can anyone
            deliver new nuclear technology in the US under the present rules
            of the game. These new technologies
            cannot be prudently licensed without fullscale, rigorous prototype
            testing. But NRC says you cant test without a license, Until
            this Catch 22 is addressed, there will be no new nuclear in
            the United States.

            1. @Jack Devanney

              You’re correct. While I wish it was already done or at least done in time to match your company’s needs, I am moderately optimistic that the message is getting through.

              By 2020, I believe that we will have a process for building and rigorously testing full scale prototype nuclear fission power plants — not just reactors, mind you. When the process is in place with the requirements clear, it should be possible to plan and finance such a machine as an integral part of a product development effort. Until that happens, however, the US is destined to fall further and further behind.

              The US Navy used such an approach for most of its early, second and third generation plants.

  4. Sooooo, why did we need to build our own MOX plant in the first place? In 2011 it was decided to shut down the Sellafield MOX plant in the UK because of lack of orders from Japan. The MELOX MOX plant in France is still operational and producing MOX for a variety of customers (http://www.areva.com/EN/operations-1206/melox.html). Japan will have their JMOX facility operational at some point in the future too. How many MOX plants does the world need?

    I’m sure any of these facilities would have been glad to be paid for the extra MOX production contracts, and it certainly would have cost less than the 5+ billions of $ we’re spending on building the US MOX plant.

    Why was this option not considered? Was DOE just afraid to ship WGPu abroad? This would make little sense, since both the UK and France have plenty of their own plutonium stockpiles.

  5. I understand that CANDU reactors were considered and found to be quite capable of “disposing” the MOX. That was before the US decided to build the SRS MOX plant, now cancelled.

  6. MOX is a tremendous waste of time and money. Much better to recycle with the IFR and maybe even make some new fuel along the way.

    1. Well yes. But IFR’s plutonium economy is what this article is about. GE-H sent NRC a 500 page license outline proposal in 2010, and again in 2011. They were essentially told NRC was busy with light water SMRs and not to bother. So GE-H pursued — and obtained — ESBWR design approval instead. See Jack Devanney’s comment above.

  7. UK reprocessed a lot of spent Magnox fuel which is superior plutonium to that found in PWR/BWR. Sadly it looks like they want to make MOX fuel with it too: http://analysis.nuclearenergyinsider.com/waste-management/uk-steer-plutonium-processing-projects-year-end

    So much rubbish written by UK NDA on this. They are desperate to turn UK plutonium into MOX. It’s all they ever wanted. In the UK GE-Hitachi will have to fight off the whole nuclear establishment NDA, ONR, … It’s terribly sad that NDA have any say at all in what reactors UK should use.

    My preferred options for plutonium, keep it
    * kickstart the thorium fuel cycle with it
    * fire up fast molten salt fast reactors
    * fire up PRISM
    * CANDU using Pu/Th fuel!

    My least preferred options are those suggested by NDA:
    * MOX
    * disposal

    What is the charm of MOX? The waste stream has even more long-lived actinides than could ever be dreamt of from LEU. MOX looks like an anti-nuke’s wet dream. What am I missing? What is so good about MOX?

    1. What is the charm of MOX?

      You can use it in reactors that have already been built, that are already operating, and that would require only relatively minor modifications to use the stuff. The alternative is to design, test, license, and build a reactor based on completely different technology. The difference in time scale and risk of the two approaches should be obvious.

      Why is this so difficult to understand?

      The waste stream has even more long-lived actinides than could ever be dreamt of from LEU.

      That’s because you’ve done more with and extracted more energy out of the fuel. For a geological repository, plutonium is the long-lived actinide that one worries about the most. By burning some of it via recycling the fuel once or twice, you’ve reduced the problem.

      But if you’re worried about the actinides, then build a few specially designed actinide-burning reactors to take care of the problem. It will take only a few of these reactors to dispose of almost all of the actinides from a fleet of LWRs, including some LWRs running on MOX.

      That’s the long-term solution, however. In case you haven’t been paying attention, I should point out that the ideas being floated as alternatives to the DOE’s MOX Project amount to finding ways to just bury the plutonium in the ground. For proliferation reasons, these disposal methods will be designed to render the plutonium nonrecoverable.

      Simply put, we just don’t have time for dreams and fantasies about the “perfect” solution.

      1. The waste from MOX fuel is more toxic because the neutronics of plutonium-239 in water-moderated reactors are not very good. They are worse than either uranium-233, or uranium-235; which are the other two fissile materials we could use. More than a quarter of the plutonium-239 captures a neutron to become plutonium-240 which has a half-life = 6563 years.

        Nor is fuel fabrication particularly cheap. MOX fuel is more expensive to make than LEU, and reactor operators find it less desirable because the spent fuel is problematic with far more actinides in it. Those actinides often have half-lives measured in hundreds or thousands of years. So they are quite radioactive and last a long time too.

        If we want to use bred fuel in thermal neutron reactors, we should use thorium to make uranium-233 which is has the best neutronics of all, so makes the least amount of long-lived actinides. Any plutonium we have is best used in fast reactors, or saved until it can be. It’s not as if anyone actually needs or wants MOX.

        1. This article has been very instructive about why the nuclear community in the US can accomplish nothing these days. On one hand, we see yet again the willful failure to follow up on anything to completion. After spending over $4 billion, what does the US government want to do? Chuck it. That’s almost $5 billion flushed down the toilet.

          Is it any wonder that I have friends and colleagues who are now retiring — guys that have spent most of their careers working on various DOE projects, dozens of projects — who tell me that they never worked on a DOE project that actually went to completion and accomplished its goal?

          This is a result of a collusion between two groups that are the enemy of progress in nuclear technology.

          The first group consists of the bean-counters, who have “discovered” that it’s “cheaper” just to build a better trash can. Of course, in this analysis they consider only the cost of disposing of the weapons Pu; they don’t consider the possibility of converting the MOX facility to process reactor-grade Pu, like they do in France, which vastly increases the value of the facility in the long term. (Or maybe they do, and that’s what they secretly don’t want to happen.)

          The other group consists of the techno-nerds who are attracted to new, shiny objects worse than any child with severe ADHD. Instead of building anything, they spend all their time whining about stuff and pointing out how their (fill-in-the-blank) design is so much better. These folks are better off spending their careers as college professors, so that they can publish lots of papers on their paper reactors, and after they retire, having built nothing outside of the laboratory, they can pat themselves on the back on how clever their ideas were.

          When they start influencing public policy and affecting the decisions of industry, that’s when the problems begin. That’s how we got to where we are now.

          The waste from MOX fuel is more toxic because the neutronics of plutonium-239 in water-moderated reactors are not very good.

          Who cares? That can be handled by proper core design.

          More than a quarter of the plutonium-239 captures a neutron to become plutonium-240 which has a half-life = 6563 years.

          This is a feature of the process that keeps the nonproliferation folks quiet.

          Nor is fuel fabrication particularly cheap. MOX fuel is more expensive to make than LEU, …

          I hate to break it to you, but any new technology is going to be more expensive than the status quo that has been around for more than half a century.

          Those actinides often have half-lives measured in hundreds or thousands of years. So they are quite radioactive and last a long time too.

          The main actinide that is the limiting factor — that is the greatest challenge — for geological repositories in the long term is plutonium.

          If we want to use bred fuel in thermal neutron reactors, we should use thorium to make uranium-233 which is has the best neutronics of all, so makes the least amount of long-lived actinides.

          You can’t talk about what is “cheaper” or “better” without doing a through economic analysis that considers all options, which is what you have not done. Random talking points don’t cut it.

          A proper economic analysis for going forward must include a Technology Readiness Assessment (TRA); otherwise, you’re just talking about fairy tales. I can give you a back-of-the-envelope TRA right here:

          The last thermal Th/U reactor in the US was shut down in 1989 — over a quarter of a century ago. It wasn’t considered a success (and it’s now a natural gas plant). That reactor used HEU as its driver fuel, something that is not going to happen again in the US anytime in the foreseeable future. (And if you want to talk about expensive, do you know how much it costs to produce HEU fuel?)

          Of all of the technologies we have been discussing, MOX is the only one that is currently deployed on a large, industrial scale. France today gets 17% of its (total) electricity from MOX, and that’s from the stuff that is pulled out of used LWR fuel.

          I’m sorry that I have to point out the obvious (again), but this is why MOX has been the preferred short-term path forward. Is it perfect? No. But wise men don’t let the perfect be the enemy of the good.

    2. What is the charm of MOX?

      It renders weapons-grade Pu militarily unusable by adding large amounts of isotopes 240 and 241 to what does not fission, thus meeting arms-reduction treaty obligations.

      Reprocessed Pu from LWR fuel isn’t weaponizable, so the only reason to use it as MOX is to get rid of (a large fraction of) it.

      1. MOX is a political requirement not an economic one. Thanks for telling it so succinctly, Engineer-Poet. Your posts are always some of the best.