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  1. I find the prospects for nigh-complete decarbonization of built up areas to be a very interesting prospect of SMRs.  The Xe-100, with its 400 yard accident planning boundary, is suitable for placement in e.g. commercial zones in cities.  This would allow its waste heat to be used for space heat.  120 MW of waste heat is the equivalent of 7.78 tons of methane per hour.  That’s about 4095 therms/hr, 98000 therms/day.  That’s enough to heat something like 30-35000 homes in January here at 45° N.

    Another possibility is the freeing of larger island grids from the tyranny of petroleum.  Hawaii is a case in point.  Oahu’s grid is far too small to handle a GW-scale power plant, but a number of NuScales or Xe-100s would do the job and probably cheaper than oil.  The reduced cost might make it economic to run HVDC cables to less-populated islands, decarbonizing them too.

    1. I did some work at a hydro plant years ago that was located 40 miles from a Metropolitan area. The hydro plant sometimes had to operate at times not necessarily for power, but to minimize voltage drop across the 40 miles of line.

      Is there the possibility that SMRs could be plopped at a substation and eliminate the expensive building of additional transmission lines? It could keep the voltage to the proper level and provide power. Could SMRs give rise to additional municipalities generating their own power and reducing the rates of the taxpayers they serve?

      Could these be nearly totally remote controlled with minimal security and operating staffs? Would local emergency plans be greatly simplified? Too many requirements may force an ever increasing size to pay for the requirements.

      I learned a new word with this one, “shibboleth.” Thanks for the piece.

  2. The biggest advantage of SMR is that they can be mass produced and deployed far out to sea for the production of methanol and other synthetic hydrocarbon fuels. Such fuels could be distributed by tankers (nuclear or methanol fueled) to any coastal location in the world.

    Methanol is an excellent replacement for natural gas in natural gas power plants and only requires relatively cheap modifications to such facilities. Reformed methanol fuel cell power plants could also be used as peak load power facilities.

    So the existing US natural gas electric power infrastructure could be easily and cheaply modified to use methanol produced at sea from remotely sited floating nuclear reactors.

    Carbon neutral methanol from nuclear energy can also be easily converted into dimethyl ether (a diesel fuel substitute) gasoline and even jet fuel– all carbon neutral. And, of course, methanol can be used as an automobile fuel itself in internal combustion engines and in hybrid fuel cell engines.

    Replacing fossil fuels for electricity and transportation with synthetic fuels produced at sea would require the mass production of tens of thousands of small remotely deployed nuclear reactors and probably the eventual extraction of uranium from seawater.

    But NuScale of Oreogon is already working with a Canadian company, Prodigy Clean Energy, to develop and deploy floating nuclear energy barges.

    Russia, of course, is already deploying small floating reactors. And Europe and China both plan to deploy floating nuclear reactors.

    1. “…the eventual extraction of uranium from seawater.”

      This seems to be another meme concept for several reasons. Nobody seems to mention the obvious challenges of biofouling of the sorbents – everything quickly crusts in the ocean – hulls are often painted with sacrificial copper. Additionally, to add perspective regarding relative concentrations of solutes, the EPA allows 30 ppb Uranium in drinking water, and some wells in rocky places exceed 900 ppb.* The cutoff for negligible blood lead in children is 500 ppb**, and we wouldn’t consider mining them. Ocean uranium extraction isn’t fake science, but it is ‘bad science’. The wonderful people at ORNL, JAEA, etc., have investigated many other things that are “possible” but wholly impractical – It’s not their fault. Humanity has never run out of any mineral by exploiting it until exhaustion. Whenever reserves of whatever start to dwindle, price increases and exploration and mining lower grade ores becomes incentivized – naturally, we would exploit crustal deposits of 100 ppm U before floating Rhode Island sized mats of polyethylene fiber. We already have massive gyres of plastic in the ocean clogging the guts of every sea creature. To me, stating that the ocean has 4.5E9 tons of uranium dissolved in it garners a big, “so what?” The uranium there is the very definition of a vanishing trace.
      * https://portal.ct.gov/-/media/Departments-and-Agencies/DPH/dph/environmental_health/private_wells/2018-Downloads/050818-uranium_in_well_water_September_2016.pdf
      ** https://www.cdc.gov/nceh/lead/advisory/acclpp/actions-blls.htm

      1. 50ppb on the blood lead, forgot 1dL is 100ml. Still an order of magnitude greater than the 3ppb of U in seawater.

      2. I’m also dubious of uranium from sea water extraction. There’s an abundant resource on land.

        I often think of the fact that there’s an area in the US where the natural gas supply used to contain He in concentrations up to 30%.

        Considering fact that He is an alpha particle that picked up a couple electrons. That implies there’s likely to be deposits of alpha-emitters below those helium-laced pockets of gas.

      3. Yes, you are right there. The crustal concentration of uranium is 1.8 ppm, implying about 40e12 tonnes U. If current global consumption remains around 40,000 tonnes per year (it is more like 60 kt/a), that ultimate resource would last a billion years. If used fuel were being recycled into fast reactors, that would be 200 billion years. However even that is considered to be a finite resource, so does not qualify as “sustainable” in the current EU taxonomy for carbon tax credits. Let’s hope the EU changes the criterion soon.

            1. My reading on the subject indicates that the red giant phase of G-class stars lasts only a few hundred million years due to the prodigious output of such stars, so 10 billion years from now the Sun will be about 80% planetary nebula and 20% helium-rich white dwarf.

      4. I used to be skeptical of seawater uranium too, but biofouling isn’t a valid reason… the polymers are quite abiotic and economical schemes require short extraction cycles anyway.

        Main reason why I changed my mind was advances in materials (and secondarily simpler cheaper geometry such as anchored braids).

        Here is some recent research which is encouraging:


        That said, in situ leach has also made terrestrial mining a lot lower impact.

        1. Biofouling isn’t valid? Sure PE is abiotic, we use it for everything from water pipes to food containers, but that doesn’t make it any less of a substrate for biofilms, and simply stating it ‘won’t be a problem’ is not a valid counter argument. People often have trouble visualizing scales involving simultaneously huge and vanishingly small quantities taken together… Any civilization that is harvesting uranium from the ocean is taking its last gasps.

        2. As a geophysicist, I worked to guide uranium explorers to prospective areas. (And yes, there’s plenty it.) Colleagues monitor the rehabilitation after mining, which is particularly demanding because all of the uranium daughters are left behind in spoil made pervious by the processing until weathering seals it again. Above ground mining can be inspected for any mess, whereas in situ mining is underground and any damage is hidden. (Even then, insignificant compared to damage by underground carbon dioxide sequestration schemes!) Although thousands of times more dilute than ore, uranium can be extracted from seawater by itself, leaving the radioactive daughters dispersed harmlessly in the wider ocean – by Nature herself.

      5. Technology and material science is always advancing, what might be impractical and too expensive today probably won’t be in a few decades. Not that we’d need the uranium from seawater on that timescale anyway.

        It’s not just slow spectrum reactors that are rapidly being developed, there are a number of fast spectrum designs in the works. Some of them waste burners.

        It’s easy to see a system developing – including SMRs – where slow spectrum solid fueled reactors provide the fuel in the form of spent fuel for fast spectrum molten salt reactors. Which in turn can breed as much fissiles as needed to power slow spectrum reactors. Even depleted uranium becomes a fuel source at the fast spectrum and there are vast stockpiles of that.

        When nuclear power becomes the main economic and technological driver on Earth – which will have to happen if we want to survive – we’ll stop asking “what can we do?” in regards to nuclear power and fuel cycles and be faced with a pretty nice alternative.

        ‘What can’t we do?”.

  3. ‘Indian PHWRs also have many of the characteristics of modern SMRs, including power rating’

    The 700MW power output of the latest Indian IPHWR is identical to the that of the Candu 6E. Given the events surrounding Canada’s anti nuclear Harper government giveaway of its $23B investment in AECL in 2011, it’s likely the Indians have access to the Candu’s blueprints.

  4. The comment quoted below is from a poet on works
    of art. If you believe that works of engineering, well done,
    have something in common with works of art, then what
    he says is relevant.

    From Writer’s Almanac, 8 Oct 2021:

    He said, “I think survival is at stake for all of us all the time. … Every poem, every work of art, everything that is well done, well made, well said, generously given, adds to our chances of survival.”

    1. The quoted poet is Philip Booth, whose birthday is today (08 Oct 2021).
      The Writer’s Almanac says more about his life and works.

  5. I got here after accidentally coming across your post “Was Arnie Gundersen a Licensed Reactor Operator and Senior VP Nuclear Licensee?” and once here, read this piece, which I found interesting, but have no comments on it specifically.

    Your post on Gunderson is timely for me. I have been making small edits to the Wikipedia article on the accident at Three Mile Island. (https://en.wikipedia.org/wiki/Three_Mile_Island_accident). Some of Gunderson’s claims are included on the page. I’ve already added well-sourced information that refutes one of his claims. I’m not a highly experienced Wikipedia editor so I am moving slowly and carefully to provide objective information. I would like to further refute his claims and credibility. The information in your post helps.

    My professional background before retiring was in nuclear power—first in the nuclear navy as a nuclear mechanic, then in commercial nuclear power as a non-licensed operator, reactor operator, and, after leaving the Operations Department, senior reactor operator licensed instructor. After retiring, I worked periodically as a contracted operations instructor until December 2017.

    1. The reactor engineers I work with occasionally joke about Arnie Gundersen… He is alarmist disinformation incarnate.

    2. Gunderson’s Wikipedia page, second sentence, used to say, “His curriculum vitae[3] shows Gundersen is a licensed Critical Facility Reactor Operator from 1971-1972.[4]”

      It now says, “Gunderson was a licensed reactor operator from 1971-1972 on Rensselaer Polytechnic Institute’s zero-power open-pool university research reactor at the Reactor Critical Facility in Schenectady, New York,[3] where he was a nuclear engineering graduate student.[4][5]” https://en.wikipedia.org/wiki/Arnold_Gundersen

      I’ve been having fun learning how to better edit Wikipedia pages and correctly cite sources. I deleted the poorly structured references in that sentence and replaced them with improved version and added a reference on the reactor, with a quote “The Rensselaer Polytechnic Institute (RPI) Reactor Critical Facility (RCF) has provided hands-on education and training for RPI and other student for almost a quarter of a century. The RCF was built in the 1950s by the American Locomotive Company (ALCO) as a critical facility in which to carry out experiements in support of the Army Package power(sic) Reactor (APPR) program. A number of APPRs were built and operated. In the middle 1960s, ALCO went out of business and provided the facility to RPI. Since that time, RPI has operated the RCF primarily in a teaching mode in the nuclear engineering department, although limited amounts of reactor research, activation analysis, and reactivity assays have been carried out as well.”

      1. Mike – Your decision to become a skilled and well-informed Wikipedia editor should pay dividends. Thank you for your efforts. I hope you continue to enjoy the power it brings to your voice.

    3. Hi Mike, and welcome to Atomic Insights! At the very top of the page, in fine white print on a blue background, you will find an obscure little tab labeled “Archives”.

      If you are of the Dungeons and Dragons bent, click on “Archives” and enter “Three Mile Island” in its search bar.

      Rod has several articles of interest, albeit one of the more interesting was written by guest author Mike Derivan, who “was the shift supervisor at the Davis Besse Nuclear Power Plant (DBNPP) on September 24, 1977 when it experienced an event that started out almost exactly like the event at Three Mile Island on March 28, 1979.”

      There were a lot of lessons to be learned there. Some of them eventually were.


      1. Thanks, Ed

        I’m familiar with the name Mike Derivan, just wouldn’t have been able to say in what connection. I’m also familiar with the 1977 DB event though not to the level that I’m seeing already in some of what you referred me to.

        In one (or more) of my EOP classes that dealt with small break LOCA, I discussed the PORV sticking open at other B&W facilities. I had actually found documentation that it had happened at ANO, too. I don’t remember when and, not working out there anymore, wouldn’t be able to find it.

        Interestingly, as I went to the link you provided, I also had the Rogavin report up on another screen where it is talking about the training of the operators and the procedures not addressing a pressurizer steam space leak.

        Again, thanks

    4. At the time of the Fukushima accident I remember Gundersen making claims that 1 million lives would be lost as a result of the radioactive material released there. So I did a quick online search and it brought me right back to this site which often happens in regards to nuclear power. Rod Adams is one of the best resources online for nuclear power and has been for years.


      There is also the “work” of Helen Caldicott and her making similar claims as Gundersen about the Chernobyl accident. She also claimed that almost 1 million people died as a result of radiation released there. George Monbiot, the British environmental journalist got into a running battle with Caldicott and he demonstrated how her claims often contradicted her own books.

      It was Caldicott who was claiming North America would become uninhabitable if the SNF stocks at Fukushima caught fire and she was planning to move to South America. A study done by Lawrence Livermore found that in the worst case scenario of a SNF fire at Fukushima the immediate area would have to be evacuated and sites as far south as Tokyo people would have to remain indoors until cleanup was done.

      The more people out there debunking nuclear power alarmism the better off we all are.

  6. I’ve been following the science of climate change for 40 years, everything that was predicted way back then and worse has come to pass. What is being predicted now is even starker, the viability of essential ecosystems is rapidly disappearing. Whether it’s coral reef systems or oceanic kelp forests.

    On land we have a transition to conditions that become increasingly hostile, this year’s record North American heat dome could become a frequent occurrence. Here in British Columbia hundreds of people died from the heat and an estimated 1 billion marine organisms died on our coast. Then the massive wildfires take off in the hot dry conditions.

    This is no longer a discussion on the ideal methods of generating energy to power our lives and societies. And even if it was, with its energy density, safety and available fuel, nuclear power would top the list.

    Do SMRs have a place in this long overdue transition to a real sustainable energy model, of course they do. So do all nuclear reactor designs that offer an alternative to a means of providing energy that we’ve known with a high degree of certainty have externalized costs that will soon be incalculable. That applies to coal, oil and natural gas.

    That will never be the case with nuclear power where advances in design and understanding the best operating procedures and use of the production – not just electricity but process heat and many valuable isotopic byproducts – means the sector become progressive more competitive and beneficial.

    It’s a pretty clear choice, the possibility of a bright future through nuclear power in combination with all other low carbon alternatives.

    Or following a energy model path that is already catastrophic with a growing magnitude with each decade.

    I didn’t serve in the Navy, but my American Grandfather was on an Assault Transport in the Pacific in WW II and I have deep respect for members of this service and their courage. The Navy has a principle in times of emergency, “all hands on deck” We are now in an all hands emergency and it is nuclear power technology largely developed and introduced by the US Navy that will save us.

    Just my opinion….

  7. Regarding Rod Adams’ question about what I find most exciting about
    SMRs: to me, it is their factory-based construction and decommissioning,
    which strongly suggests a revival of closed fuel cycles and nuclear recycling.

    With those changes, a drastic reduction in need for uranium mining, enrichment,
    and long-lived nuclear waste storage will likely follow. And whether the path to
    those benefits is through thermal reactors or fast, I think the main objectives to be reached despite obstacles will be verifiable safety and understanding by a well-informed
    public and government.

  8. SMRs for the most designs is a financial model more than anything else. Take Rolls Royce SMR, it is a three loop 400MWe ~1300MWth plant design similar in size to an AP600. Westinghouse developed the AP1000 from the AP600 because they didn’t see how they could make the AP600 cost competitive on price per MWh. The same issue exists with most water moderated SMRs simply due to the very strong economies of scale.

    The financial model of smaller plants may be attractive in de-regulated markets where the cost of capital for large nuclear builds largely drives the cost of the plant. The UK government even produced a graph illustrating the cost of the EPR at Hinckley if it borrowed the money at government interest rates if 2% where it fell from £90/MW with the current financial model to £45/MW.

    For HTGR plants, the economics are slightly different and due to weaker economies of scale sauce that the learning curve from building multiple plants can be more important than most reductions due to increasing size.

    Essentially the success or otherwise of SMRs is completely dependent on the technology and financing model of the market they are selling into. State backed financing will always lead to large plants being cheaper for PWRs, conversely where the cost of capital is high the switch to smaller plants can be cheaper due entirely to bringing the financing cost down. If a different technology is picked then the optimum size clearly changes

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