1. Rod,
    Is a 20 kw plant actually possible? Is it really possible to go this small? I am honestly asking because when I talk about small plants, most people say, can I get one for my house, and I have always said no, because I did not think you could actually scale down that low. Talk about a RADICAL change in power production, wow. Power your own home for 10 years on a Nuclear reactor.

    1. David it is technically possible to make nuclear power plant with as small output as 20 kW or any arbitrary number, but it becomes increasingly uneconomical for very small sizes. There is some minimum mass of fissile U-235 necessary, even when you apply all your tricks to reduce critical mass as much as possible; at some point you are just shrinking the power output, not the size of the reactor. There is some minimum regulatory burden; at some point shrinking the reactor doesn’t save you any paperwork or beaurocrat-hours.
      If you’re trying to build a base on the moon, a reactor producing only tens of kilowatts may make a lot of sense; on Earth I doubt it.

    2. David,
      I think the exact power level is classified but the reactor in the NR-1 submarine, after housekeeping loads, had the equivalent of a 50 HP outboard for propulsion. This is a demonstration of techological capability – you probably would not want to pay for it.

  2. @David – It is technically possible, though there are enormous political and economic hurdles that would have to be overcome. If done, the system would probably last for something more like 30-50 years than 10 years.

  3. @ Rod,
    Buy the house and the power for the next 50 years. Yes, I understand the political and economic hurdles, but the concept is staggering. This would be the basis for a truly distributed grid. Factories and office buildings could each have their own power. I can see the worries about proliferation already, but what an idea! I was wondering what a small Nuke could do for steel manufacturing or even Aluminum manufacturing and started to do some calculations. But that type of investment would be really long term thinking for an investor. This means that what Docforsight was looking for in his project is actually possible, though not practically available today. Sorry for rambling, but I just had a stroke of total amazement.

    1. @david — Since I haven’t actually lived in a 3rd World country, I had little reference point for what is needed when no grid exists. Oh, I’ve done some work in Mexico (Baja peninsula) and saw the rudimentary system there but not in an area where nothing exists. At the risk of being annoying, check out the “projects” tab on http://www.self.org — if only to gain a perspective on the monumental task before us.
      To many of these people, having ‘A’ (singular) light for a few hours of night use would make a huge difference. Dwell on that a moment. It is a significant leap in every respect to go from nothing to 24×7 electric power — and that leap could easily take decades to reach many remote places or get through corrupt governments. How do we get there? Like eating an elephant – one bite at a time.

      1. @ DocForesight,
        I have been in those villages and slept in those houses and I have many friends who have done the same. I like Solar PV. I have been following it for years and it has a much better potential than wind power for long term use in remote areas. Prices are coming down. http://www.solarbuzz.com/Moduleprices.htm However, on one island I have been to they installed Solar PV in several villages. After a couple of years the systems were down due to lack of maintenance. I spent some time talking to the man who sold PV systems in that area and it seems that there were several basic problems. First, an understanding of electricity and how to use it and how not to. Second, available parts for replacement when the systems broke. And then the cash flow to actually purchase the parts needed to repair. The fishing villages usually don’t have cash flow, everything is barter. I don’t know exactly the configuration they were using so I can’t comment on the durability of the installed system. I noticed that in the Solomon Islands they spent time training the people on how to repair the system. But there is no record of how things are going today. The Indonesia model seems to be working and continuing.
        Lights are huge help in many ways and so is communication. I had been studying various power generation sources, wave, solar, wind and geothermal trying to understand what would be a real substantial help where I live. Electric here costs about 23 cents / kwh. It was when I ran across the MIT study on Modular Pebble bed reactors that I began to appreciate the amazing potential of nuclear. Until that point it was very fuzzy in my mind and I really did not have enough knowledge to have an opinion. The most remote villages will need solar PV. But for concentrated populations, even those remote ones, small nukes would be THE answer. At least in my opinion. Wish it were here today.

        1. @david –Thank you so much for your responses and sharing your experiences. My interest in nuclear was piqued by reading about the Toshiba 4S proposal for Galena, Alaska about 18 months ago. Followed links and found several excellent blogs, such as this.
          Training and maintenance will be critical for long-term success. If the villagers own the system and take an active role with it, they ought to be more responsible with it. One would hope! And I agree with you regarding concentrated populations and nuclear power plants – especially if they are modular and can be ‘ganged’ to expand with demand and grid capacity. Priority will be given to large populations while the villages will remain an afterthought for years, if not decades.
          I look at our type of system or concept as a ‘bridge until’ rather than a ‘replacement for’.

  4. Rod: ‘Pick up almost any book about nuclear energy and you will find that the prevailing wisdom is that nuclear plants must be very large in order to be competitive. This notion is widely accepted ….’
    There is probably a place for small reactors, but … I think the current prevailing wisdom is that large plants have to be absurdly expensive. I suspect that is not true. The modern design and construction techniques being used for the AP1000 are expected to lead to great reductions in cost — this is going to be demonstrated in China, if it is in fact true (with the added kicker that the Chinese ‘variant’ being planned will be a 1400 MW reactor). Designs being discussed for small reactors (sodium-cooled, or LFTR, or … ) can also be scaled to build large reactors. I’m just speculating, but I was reading the ‘white paper’ from Advanced Reactor Concepts and at the top was a lot of negative stuff about the problems with large reactors, but it seemed to me like many of those issues were self-inflicted.

  5. At the moment large plants offer an economy of scale that will guarantee that they will continue to be built for electric power markets on the larger grids. However there are smaller markets in the Far North, on isolated islands and the African and South American interior where small reactors make sense, and these are the places that will see initial deployment of these designs. There may come a time where small reactors become competitive in areas with a high population density, that are currently served by power grids, but that will be sometime coming.
    Nevertheless the potential markets that are available are not insignificant, particularly when applications like district heat, and desalination are factored in. Power for irrigation, even if desal is not a factor, could make a huge difference in the quality of life in many backward Third-World communities. The availability of a simple thing like an electric stove for each home in some regions would have a significant impact on deforestation, and so on. These are the initial areas that mini-reactors can have a real and positive impact, particularly those ‘nuclear battery’ type systems that would require limited supervision in the field.

    1. @DV82XL,
      When the price of propane in our area raised to the point where a 10 kilo tank cost 3 to 4 days wages everyone turned back to burning charcoal and the trees began to come down again. I see bare hillsides everywhere. People will cook to eat and if it cost’s too much to purchase power or fuel they will burn the stuff they see. So, yes, in a very direct way a ‘nuclear battery’ system will save forests.

      1. I have a personal adage that says that there are only two types of problem in the world: those that can be solved with access to an unlimited source of energy, and those that cannot be solved at all.

  6. Rod, I’ve been reading your blog for a couple of years now. Thank you for what you

    1. Bernie – thank you for the thoughtful comments. I suppose we will simply have to agree to disagree. I may very well be proven to be wrong, but I remember a day when similar words as yours could be written about computers. I have also had the experience of operating a reactor on a 24 x 7 basis with only 40 people. The support staffs that you mention were shared resources. The costs of the detectors, pumps, valves, heat exchangers, etc. were based on order quantity, partially because the paperwork and quality controls were identical on series produced devices.
      I have been a manufacturer and have seen the economy of unit volume at work as we made more and more of the same part.

  7. Rod what lead to me to the idea of small reactors was the idea of massive global deployment of nuclear power over the next 40 years. “How could so many reactors be built so quickly,” I asked myself, The answer, I realized, was provided by the industrial system. If you want to build a lot of anything, you mass produce them in factories. But how do you mass produce reactors in factories, how do you move them to their destination? The answer was, build them small enough to be transported by truck, barge, or rail. So then I started looking at small reactors.
    Most small reactor critics, don’t understand that they are a solution the mass reactor deployment problem.

  8. I take an intermediate position. Charles Barton (and others) have done a lot of writing on the economy of small reactors, in Charle’s case, the LFTR many of us are familiar with and big supporters of.
    For small grids and underdeveloped countries, where the entire national load maybe, say, 5 GWs but with a population of, say, 50 million (this proportion is about what Nigeria has, for example) the building of grids around smaller plants makes sense at *every* level. One can build a grid around several “nucplexes” and eventually tie them together, first for voltage control, then for load wheeling. Small plants allow this and allow for the limited grid development. It *also* allows for eventual scaling up to plants over 700MWs.
    I wrote to John Holmes (I think it was him) about the idea of powering a true high speed electric rail system in the U.S. by using small 20 to 60MW LFTRs spaced out about every 75 miles of such system with appropriate surpluses available to power development around each such small power plant, making them centers for trade, commerce and development based on these mini-nucplexes. But….
    In my mind there will always be a very large market for both large and small reactors as they can compliment each other well, especially for MSR style reactors that are so scalable they can even use interchangeable parts, salt inventory, etc.
    The issue I have is the advocacy of smaller plants in *substitution* for larger ones, that is, say, 12 100MW LFTRs instead of, say, one 1200 MW LFTR. There are, generally, way too many assumptions made by small-only advocates about the ability to ‘mass produce’ smaller reactors that per unit of energy output (UEO) it will somehow be cheaper, based solely on the idea of manufacturing core components. I think this is naive. There is FAR more that goes into a reactor/turbine/generator where smaller mass produced components are somehow more economical.
    For example, most metering would be *exactly* the same for a large plant vs a larger number of smaller ones. Take the watt-meter off the generator or what we call the “low side of the main bank transformers”. You need only 1 for each phase (A-B-C). They are all the same, mostly, reading the terminal voltage of the generator (or wattage for the wattmeters)l That’s it. 3 of ’em in total. Same meters for a large generator or 12 smaller ones. Want to guess which is more expensive to purchase, install and maintain? Temperature, radiation and host of other metering and controls could well be *cheaper* on a big unit simply because one wouldn’t need as *many*.
    I’m not arguing that this is a game-ender for any such discussion. I merely ask everyone to think what “economy of scale” actually means? Most of us have no idea how things are actually produced. For “N-Stamp” quality, much of these components are *hand made* to exacting standards that have no place in true mass production. Many smaller components, for example, like lube oil pumps, are hand made in that there is little real automation in their assembly. The stamping and miling of their impellers may well be automated but that’s about it. The ones in a “small nuclear plant” would be the *exact same* size and design as in larger plant. This is true if you build 5,000 or 200. None of it is truly ‘mass production’ which is only a reality in the mass consumer based industries such as cars, TVs, etc. When you get to bigger items, such components are not so cheap, as in the case of most industrial equipment.
    There many, many facets to this and they all have to be weighed against each other is the “many smaller vs fewer bigger” discussion.
    David Walters

    1. @David – that is a reasonable approach and one that I share, with some modifications.
      There is certainly a market for large scale machines in the 1-2 GW range. That is obvious since there are quite a few of those machines in economical operation today. However, the market narrows rather considerably if you try to go much larger. Even at those sizes, there is some economy of unit volume that has led some customers and vendors to assert that three 1100 MWe plants can be more economical than 2 1600 MWe plants.
      When I talk about series production economies, I am not talking about “mass production”. There is a significant cost reduction available in moving from one of a kind hand made devices to a production run of five or ten units. Even with the meters that you mention – the price per meter will be lower if you buy 30 than if you buy just 3. Of course, I will agree that the price for the total order will be higher for thirty than for 3 but there are other advantages to having some redundancy that cannot always be measured on the first order analysis.
      My bottom line – I am not proposing that one should consider trying to bid 50 machines at 20 MWe each against a single 1000 MWe machine if the customer is operating in a grid that already needs 1000 MWe of new capacity. The large machine would win in that case. However, I do think that a customer needing 1000 MWe in 10 years because his loads are growing at about 100 MWe each year MIGHT consider adding one mPower sized unit each year to a site large enough to host eight to ten of them if licensed mPower reactors were available and could be installed on a one per year basis with some predictability.

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