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Practical size limit to nuclear power plant?

  1. Nov 2, 2005 #1


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    Assuming the current anti-nuclear public/political climate remains in place and no new nuclear plant sites would be allowed (nor within a reasonable timeframe) why not just simply increase the existing capacity?

    For a hydro plant it makes sense there is only so much water that can be processed and needs to be managed, but nuclear seems like it could be somewhat flexible like the current coal/natural gas combination with the excess above base-load generation from the nuclear plant stored in some other form (aluminum, hydrogren, etc).

    Sure the losses may be higher and transmission lines upgraded to 1MV or more, but why not upgrade?

    Or is the simple answer the regulations and political climate would never allow it?
  2. jcsd
  3. Nov 2, 2005 #2


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    How do you want to increase capacity? Add new plants at the same sites.
    That is certainly an option. However, I don't think it buys you much. The only thing
    that you could potentially "reuse" from the existing nuclear plant are the site-specific
    studies - what's the population around the plant?, ... etc.
    However, in the 30 years since the last order for a nuclear plant that was completed,
    all the population distributions are out of date. One would have to do new site-specific
    studies anyway.
    The local residents may have become accustomed to having a nuclear power plant in
    their town - but they're not the ones that will be filing lawsuits to block the plant. The
    anti-nukes will flock for miles around to protest the plant.
    When I was a graduate student at MIT, Boston / Cambridge was the hotbed of activism
    against the Seabrook nuclear power plant in New Hampshire. The fact that Seabrook
    was many miles away from Cambridge didn't quell any protest.

    Dr. Gregory Greenman
  4. Nov 2, 2005 #3


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    How odd that in a country where the basic premise of majority rule that a loud vocal minority can be so effective.

    Yes, I thought maybe it would be a compromise to leverage the specific sites, since they likely have plenty of setback area and (guessing wildly) spare land to build on. As you pointed out, the locals accept it and it likely has some economic benefit to them if there are any metal manufacturing or whatnot still associated with power generation.

    Are we (as a country) really that myopic to keep depending on an old infrastructure while other countries progress? Its almost like the high price of oil may indirectly raise the price of goal/natural gas since they are transported with oil fueled machines. And the technology has (at least as reported from Europe) progressed considerably since the last reactor was built here in the US, so the high ROI cost could be much lower than the billions for the old technology, correct?

    While on the topic, is this article even 80% correct on its technical information? If so, that sounds like a very promising development too.
  5. Nov 2, 2005 #4


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    Two consortia and some individual utilities are already looking at plans for advanced reactors at current sites.

    Nustart Energy (http://www.nustartenergy.com/DisplayArticle.aspx?ID=20050922-1 [Broken]) Entergy's Grand Gulf site (Unit 1 operating on a site for at least 2) and TVA's Bellefonte site (two partially complete PWRs :rolleyes: ). Entergy has even considered a sister unit at Waterford.

    The reactor at Grand Gulf would most likely be an advanced BWR, and the units at Bellefonte and Waterford would likely be advanced PWRs.

    I suspect capacity would be on the order of 1000 MWe (1 GWe) each, and possibly 1200-1500 MWe. Single reactor units have not gone beyond 1600 MWe (TVO-3, Areva's EPR), which seems a practical limit.

    from http://www.nuclear.com/index-Nuclear_power.html
    [Ref: Engineering News-Record, "Bechtel Joins Teams To Develop Next-Generation Nuclear Plants", September 26, 2005, p. 7]

    As for the development of nuclear power, after TMI-2's accident, the utilities became weary of new units, and plans for more than 100 other plants were indefinitely deferred or cancelled. Anti-nuclear sentiment was part of that. Although the anti-nuclear movement was very vocal, most of the public was ambivalent or uncertain, and lawmakers (politicians) and regulators imposed more stringent conditions on nuclear power - enough to discourage utilities from new plants.

    China may be overly optimistic on their power requirements.
    Last edited by a moderator: May 2, 2017
  6. Nov 2, 2005 #5


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    Interesting article, and I also found different and much more informative articles on wikipedia that explained the range of existing reactors and the Nuclear Power 2010 and Energy Policy Act of 2005.


    The reason I posted was because of the range of power production from 40MW to 2000MW listed on the following page:

    Utopic and over-simplified, if the nuclear plants averaged a small a size (and they don't with 104 plants at 96,000MW for 923MW each according to the article) then increasing their capacity could allow for a direct reduction in coal plants for baseline loads. Which from a pollution standpoint offers the best incentives.

    I also didn't realise the economics of the situation were such a complicated matter.
  7. Nov 2, 2005 #6


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    I am not aware of any single nuclear unit putting out 2000 MWe, which would mean a thermal generation rate of about 6000 MWt. The biggest units in the US generate about 3850 MWt.

    The plans for new units are perhaps fluid, but ESBWR seems likely, as Westinghouse's APWR.

    Siting is an issue - not only from an evironmental impact, but also with respect to main transmission lines, both geographically and capacity-wise, in relation to the load.

    It's not only economics, which includes many factors including reliability, but also safety is a factor.
  8. Nov 3, 2005 #7
    You are correct that no single nuke puts out 2000 MWe, the turbine-generator is currently the limiting component at ~1600 MWe or 1700+ MVA.

    There was a plan to place several 1500 MWth nukes on a site and drive one large turbine-generator but it never got very far IIRC.
  9. Nov 3, 2005 #8


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    Well this confirms it -

    Siemens to supply world’s largest steam turbine-generator for the Olkiluoto 3 nuclear power plant


    Siemens was the first to introduced the modern advanced steam turbine design - particularly azimuthally curved blading which increased the steam thermo-fluidmechanical to turbine-mechanical energy conversion.
  10. Nov 3, 2005 #9


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    Yeah, I heard about the modular units - both modular gas and modular fast reactors - which could be combined in pairs and triplets with a common steam header. The benefit there is high station capacity factor because one reactor could be brought down for refueling/maintenance, while the other unit(s) continue to run. This is attractive as long as there is no common mode failure.

    On the other hand, one puts all of one's eggs in one basket with respect to the turbogenerator set.

    Another thought on the size limitation, at least currently and beyound the T/G set, is the pressure vessel size and power density of the core. The US has essentially lost its capability to produce large PV's or the kind needed for nuclear reactors. Instead these components are made overseas in Japan (Mitsubishi), Italy (Ansaldo), Canada and perhaps a few other places. Possibly Trinity Industries (Texas) might be qualified, but they have not manufactured a PV for a nuclear unit.

    Power density in the core is another issue as it relates to the structural integrity of the fuel and structural components. There are still problems with today's core conditions, and some advanced concepts with high temperatures and flows will have additional problems.
    Last edited: Nov 3, 2005
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