1. Why shouldn’t nuclear plants compete with coal? From a cost perspective, utilities (and thus ratepayers) will see a four-fold advantage. From an environmental perspective, one of the best things for a nuclear plant is to replace a coal facility so that people can experience the pollutant levels going down.

  2. Some nuclear plants can compete economically with coal in many areas, but not all. There are parts of the US where coal is so abundant that it only costs 6 dollars per ton at the mine. (On a cost per unit heat basis, that is less than 1/10th the current price of natural gas.)
    There are many other areas where coal costs $60 or more per ton – it is a bulky fuel so delivery costs can add up fast. Part of my point in the original post is that cost is something that must be addressed individually with each project.
    Nuclear can ALWAYS win any environmental impact contest with coal.
    The nuclear plants that AAE intends to build are too small to economically compete directly against large coal facilities in areas with cheap coal, while it is possible that the designs proposed by others may be able to do so.
    Our cost disadvantage in large scale markets is mostly because the manning levels are higher on a per unit power basis and because the cost of licensing the plant must be ammortized over a smaller output. We think we have a viable business model because our competition has some of the same scale disadvantages.

  3. One of the main economic problems (other than regulatory ratcheting) of nuclear power has always been that it has been viewed as “expansion.” Nuclear power plants, generally, did not replace coal, but were added with electricity demand. This resulted in coal staying while the 1973 energy crisis choked nuclear expansion and the subsequently popular anti-nuclear movement kept it down when demand recovered.
    You know this.
    My point is that if any nuclear plant can win any environmental impact comparison with any coal plant, why not try it? Why not go into small markets that use coal on the high end of the rate spectrum and try to replace that coal plant with a nuclear equivalent?
    Also, is there a uniform design so there’s one design license? Although I haven’t looked at 10 CFR 170-171 in detail, I understand that a uniform design lowers the licensing cost from around $5 million to a little over $3 million.

  4. Rod, what’s your expected power output, thermal efficiency and per-kW cost?  Could such a plant be built underground for a similar cost as what you project?  I’m wondering how such an engine could fit into a combined heat and power scheme.

  5. Engineer-Poet (BTW, your handle intrigues me. I earned my BS in English at the Naval Academy before volunteering for duty as a nuclear trained submarine officer. I am pretty sure I am one of a very small group of English Majors that have served as the Engineer Officer of a nuclear submarine. I never was much for poetry, however. I prefer prose.)
    Answering your questions:
    Expected power output – between 1 and 50 MWe with 5-10 MW for the most likely first commercial version.
    Thermal efficiency – without cogeneration it will be about 30%, with it it could reach about 55-60%.
    Cost per kilowatt hour – less than 10 USD cents.

  6. Hmmm, what’s keeping the total energy recovery from exceeding 60%?
    How much difficulty/expense would it add to construct such a machine in a mine?  My speculation is that much of the political opposition to nuclear is the perceived threat of meltdown or terrorist attack, which isolation beneath impervious layers of rock would eliminate.  With isolation provided by mass rather than distance, you could locate the plant(s) beneath cities and use the waste heat for space heat.  When natural gas hits a dollar a therm, the waste heat is worth more than 3¢/kWh all by itself.

  7. Engineer-Poet asks “What is keeping total energy recovery from exceeding 60%” – mainly I prefer to under promise and over deliver.
    With regard to locating plants underground – if put in places that are already excavated, very little additional cost will be imposed. If there is a need to dig, obviously the cost of the plant will increase by the cost of the excavation.
    IOW, I like the idea of underground plants as much as I do the idea of underwater plants. “Remain undetected” is one of the maxims of a good submariner and I think it is a pretty fair goal for an environmentalist.

  8. The problem with over-delivering is that the customer may have under-designed their handling systems, or may have foregone opportunities to use the total available heat.
    BTW, I looked at your site and can’t see why you prefer nitrogen to neon or argon; the ratio of specific heats of noble gases appears to be more favorable.

  9. Engineer-Poet:
    I asked myself the following questions when choosing the working fluid:
    Have you ever seen a turbo-generator that has been designed to operate with neon or argon?
    In comparison, have you ever seen a turbo-generator designed to operate with nitrogen or mostly nitrogen (air is 80% N2).
    How much do aron and neon cost per unit volume and how does that compare to N2?
    How much will the cost of those gases increase if the market suddenly needs a lot more when Adams Engines succeed?
    What is the activation potential of argon, neon and N2?
    The answers led me to N2.

  10. At 18 ppm of the atmosphere, I don’t see neon running out in the next millenium.  Its activation products have half-lives of minutes.
    Noble gases like helium are favored in Stirling engines because the ratio of specific heats allows greater pressure/temperature swings with smaller volume changes.  But if it wouldn’t boost your thermal efficiency enough to pay for itself, I guess you don’t care.

  11. Engineer-Poet:
    N2’s concentration is about 800,000 ppm in the atmosphere.
    The specific heat of the gas has little to no impact on the thermal efficiency of a closed Brayton Cycle engine. (Ref: Influence of Working-Fluid Characteristics on the Design of Closed Cycle Gas Turbines; S. T. Robinson, ASME paper number 57-GTP–13 published March 18, 1957)
    I have only a passing knowledge of Stirling engines, so I cannot comment on the effects for that heat engine.

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