Atomic Show #300 - Dr. Lindsay Krall, "Nuclear Waste from Small Modular Reactors" 1

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  1. Hi Rod,
    I listened to the podcast interview with Dr. Lindsay Kroll and I thought
    it was a bit surreal and somewhat entertaining from a black humor
    perspective. It reminded me of an interrogation scene from “Law
    and Order”.

    FWIW, it should be noted that the paper was discussed on this site
    back in August as part of the blog entry titled “Why are smaller reactors
    attracting so much interest?” (04 Aug 2022)

  2. Macfarlane’s “Burning waste or playing with fire?” article published in the Bulletin of Atomic Scientists, 09/2018 was the most levelheaded Gen3/4 reality check I had read until this PNAS article superseded it with more detail. The authors place high importance on high-level waste stability in [hypothetical] geologic repositories. Whether or not we eventually build such a repository, it is hard to fault the authors for highlighting the hand-waviness of the “back-end” of the fuel cycles pitched for MSRs, SFRs, PBMRs, etc. All of these alternative reactors are DOA without a CRADLE TO GRAVE PLAN for their waste streams that is NO LESS STABLE, TIMELESS, or MORE EXPENSIVE than putting H/LWR fuel in air-cooled shielded trashcans on a concrete pad.

    ASIDE: Despite the 60-year licensed lifespan, the casks obviously have an INDEFINITE lifespan – the rain wets them and the sun dries them. Steel components can be designed for infinite fatigue life if the stress field/cycle is well-understood (examples in your car).

    The discharge burnup [easily] calculated from chapter 4 of the NuScale Design Certification (i.e. ~35 GWD/TU) is about 70% of what we achieve in the existing LWRs; the enrichment required to achieve this lesser burnup is incrementally ~0.7% higher. In various forums, I’ve used these simple ratios to demonstrate that NuScale will generate 40% more spent fuel/MWe than fleet LWRs, and will have similarly elevated fuel costs. The authors of the PNAS article calculate NuScale will produce 70% more waste. FWIW, CANDU generates 600% more waste by the same calculation with a slight, yet calculable improvement in fuel utilization. It is easy to show the HALEU PBMR types will generate 20X the waste volume of LWRs and the fuel will prove difficult to reprocess (if ever desired).

    The authors clearly value nuclear power, argue for incremental improvements to LWR technology and highlight flaws and gaps in proposed [meme] reactors that are obvious, even to a lowly utility employee like myself.

    Let this sink in: “reprocessing, recycling, and dilution will not eliminate the need for storage, transportation, treatment and disposal of radioactive materials.”

    A patriotic quote from the 09/2018 article showing the intent of what is mistaken by startups as criticism: “We urge policymakers to critically assess non-traditional fuel cycles, including the feasibility of managing their unusual waste streams, any loopholes that could commit the American public to financing quasi-reprocessing operations, and the motivation to rapidly deploy these technologies.”

    1. Michael Scarangella writes:

      > Let this sink in: “reprocessing, recycling, and dilution will not eliminate
      > the need for storage, transportation, treatment and disposal of radioactive
      > materials.”

      That may be true, but at risk of supporting the current thing since 1970,
      I will note that switching fuel cycles from U238-P239 to Th232-U233 would,
      if successful, reduce the radiotoxic lifetime of used fuel from 100Ks of
      years to less than 500 years.


      This fact argues in favor of Deep Isolation’s design concept of vendor-specific
      borehole technology, vs. the one-size-fits-all Yucca Mountain mega-disposal site.

      Reprocessing/recycling at an SMR plant could accomplish the same thing
      as using Thorium fuel but without having to switch fuel cycles.

      Both of these approaches may be expensive in their current form, but my
      understanding of DOE’s funding boost is that its purpose is to enable
      developers to do R&D to investigate ways of reducing cost while improving
      safety, security, and other things.

  3. “This study also neglects to consider reprocessing, recycling, and dilution …”

    In so saying, this study wants us to neglect the needs of future generations of fast-neutron reactors. This study also neglects to place the oncoming wave of small nuclear reactors in the context of the imperative to replace all fossil fuels by 2050. This study also neglects to compare their (imagined) problems with “nuclear waste” with the overwhelmingly greater problems with waste CO2 in the atmosphere, that nuclear electricity stands to replace if it were not delayed by these imaginary difficulties.

    Understandably, this study neglects to state that the MacArthur Foundation is committed to “a peaceful world”. Greenpeace is similarly committed to “world peace”. The code attracts funding. If both organisations were to change their commitment to “a fossil-free world” they could do far more service to the world’s humanity, environment and prosperity.

    1. Roger Clifton writes:

      > If both organisations were to change their commitment to “a fossil-free world”
      > they could do far more service to the world’s humanity, environment and prosperity.

      I agree. It would be beneficial to think of nuclear and “renewable” energies
      as partners in a zero-carbon collaboration rather than as rivals in a zero-sum

    2. Although I agree that political organizations like Greenpeace should adopt a
      clearly defined fact-based endorsement of a “fossil-free” world and should
      consider what it would most likely mean to make such an endorsement, I would
      not expect that such organizations would (or should) be likely to make such
      an endorsement into their primary goal at the expense of their ideological
      commitment to “world peace”, whatever they mean by that.

      I do think that making an empirically based endorsement of a “fossil-free”
      world requires an empirically based understanding of the difference between
      the explosive energy of nuclear detonations and the controlled energy of
      nuclear reactors, fast and slow as well as new and old. The difference
      is one of timescales, between the subatomic timescales of neutrons and
      protons and the molecular timescales of thermal and chemical instruments
      and mechanical feedbacks. My understanding of what enables nuclear
      reactors to work across timescale gaps is based on “delayed neutrons”
      which Wikipedia defines as follows

      In nuclear engineering, a delayed neutron is a neutron emitted after
      a nuclear fission event, by one of the fission products (or actually,
      a fission product daughter after beta decay), any time from a few
      milliseconds to a few minutes after the fission event. Neutrons born
      within 10E-14 seconds of the fission are termed “prompt neutrons”.

      My understanding of what STEM education needs in order to work
      across information gaps created by political fear of all things nuclear
      is to impart a clear understanding of what enables nuclear reactors to
      work across timescale gaps. To me, that is basic science, same as
      interstellar distance gaps and what it would take for humans to travel
      between planetary systems. It would take far longer than the entire
      existence of human societies to date.

      Because of this, there is no planet B. We have to deal with the
      realities of the planet we live on now. Starting today.

    3. MacFarlane and Krall are calling attention to Figures of Merit (FOM) that are useful for qualifying proposed reactors regardless of their proponents’ aggressive marketing claims: 1) will they be easier to operate? 2) will they more economical to operate? 3) will they make more mess while operating? 4) will they improve fuel utilization? 5) will they be safer? 6) will their decommissioning and spent fuel storage be cheaper/easier?

      Nuclear startups are trying to ride the coattails of an emotion-based, anti-technological environmental movement that hates nuclear power. Emotion is irrelevant in engineering – hand wringing about the fissile needs of “future generations” is irrelevant. Level heads can evaluate if proposed power plant designs improve on [at least most of] the basic FOM with emphasis on ECONOMICS. With startups, NuScale included, there is an apparent inversion in roles regarding proof of concept, improvement, economics. The onus should be on the originating organization to prove that a reactor concept improves the basic FOM prior to receiving gobs of tax money to build their science projects, but instead gobs of money are thrown at Kairos Power, General Fusion, Terra Power’s Nutria™, etc. No practiced engineer would imagine the basic economics and reliability of a SFR would be improved by adding a nitrate salt heat sink, or that a PBMR would become disruptive upon convolution with the MSR. This is wasteful government spending on bad ideas – cronyism – lack of creativity and evidence of systemic corruption. It’s not MacFarlane and Krall’s job to enter the vacuum of reason and highlight obvious gaps. The onus is NOT on them. Their challenges should be welcomed, considered, and addressed. The demise of any particular nuclear startup is even more certain without FOCUSING on MacFarlane and Krall’s challenges.

      1. Michael Scarangella,
        Thanks for supplying a good concise list of criteria for evaluating prospective
        entrants into the SMR market. I would add: 7) will they lower the collective
        carbon footprint and increase the reliability of electrical grids that would
        otherwise need to depend on increased use of fossil fuels to recharge
        ratepayers EVs?

        I won’t speculate further on this set of criteria. The marketplace will
        more likely decide once there are real products out there to compete
        with upkeep of the existing nuclear fleet.

      2. The author’s represent the government establishment. This establishment is communicating it’s concerns with plain language, citing difficulties in handling, transporting, storing, radioactive materials that are demonstrably less chemically stable than clad oxide, which is used in the BN800 SFR for these very reasons. The author’s note that recycling is currently not economical, and does not negate the need for storing transporting and handling unconventional fuels. With all of the unconventional startups, there is a mountain of engineering to be done, presumably at great cost, to actually implement, let alone close, their fuel cycles. There is a handful of MSR ‘startups’ – they don’t want to work together to achieve a common goal – instead they want the glory of having their own flavor become standard. There is hubris in their presumption of novelty in their designs – anybody educated in fission understands that a bucket is the simplest reactor concept (outwardly). That does not make it the simplest reactor to operate. Perhaps it is time that the ThorCons take a deep dive into the banalities of licensing transport, storage and handling mechanisms to flesh out their schemes. If the opponent (establishment) tells you why they oppose your proposal, there is work to be done – the criticism is a favor.

        1. @michael

          Without arguing your points, I’ll ask a question. If the establishment is so right, why aren’t they building more capacity to meet serious market demand?

      3. On the contrary, we must actively contradict McFarlane and Krall. Any use of the terms, easier to operate, more economical, more messy, improve fuel efficiency, safer, spent fuel, cheaper, etc are emotive slurs that would mislead the naïve to believe that reactors are faulty in those regards. Any competent engineer requires only that a reactor design should be sufficiently easy, sufficiently economical, sufficiently clean, sufficiently fuel-efficient, sufficiently safe, and sufficiently cheap. Further, used fuel should be reused over and over again until only fission products are left, to be easily buried as deeply as the fearful require.

        Fear mongering is the weapon of nuclear energy’s competitors. We should not be party to it.

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