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View Diary: Big Trouble In Arkansas w/Update (246 comments)

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  •  I'll have to argue with you here (0+ / 0-)

    Projected operating temperatures are ~700 C to keep the fuel molten--IIRC the salts melt at various points near 400 C and boil around 1400 C.

    Secondary loop would not be steam at those temperatures. One idea I've seen floated is helium running a triple-reheat closed-cycle turbine at 700 C, with an electrical conversion efficiency 50-100% higher than the steam cycle due to the higher temperature. Helium isn't easy to keep confined, but it doesn't become radioactive under neutron bombardment & isn't hazardous unless you try to breathe it without enough oxygen in the mix.*

    You should note that the MSR would not use sodium in any form. Liquid sodium was "tried in the 60s" as a working fluid for very high temperature plutonium breeder reactors; the stuff is so reactive (particularly with water) it's no wonder it was "a disaster." The MSR uses fluorides of actinides (uranium, thorium, plutonium) in solution with lithium & beryllium fluorides. The strong ionic bonds in these compounds make them extremely stable.

    I'm particularly fascinated by the possibilities of the liquid fluoride thorium reactor (LFTR) which would "burn" U-233 bred from thorium within the reactor itself & could be tweaked to gobble LWR waste. Here's a reasonably brief overview of the LFTR--you might find it interesting.

    *Note: the helium turbine is unproven technology, but it could be researched independent of the reactor, as could the reprocessing technologies that have been proposed. Considering the promise of the technology, I think a modest budget to investigate both would be money well spent.


    by Uncle Cosmo on Thu Apr 04, 2013 at 07:47:33 PM PDT

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    •  so say it's running at 800C (0+ / 0-)

      that's more then enough to have a steam explosion from any loose water.  Trust me, when a quake hits a MSR, it will have loose water around.

      Helium won't work, we don't have enough helium production.

      these kinds of plants are going to require us to go to Jupiter for helium :-(

      The SOlar Thermal industry is messing around with Molten salt, it's lots of flouro-silicates and flouro-chlorides,  but, it's heinous stuff.

      •  What part of "the MSR doesn't use water" (0+ / 0-)

        are you having trouble grasping, friend? And as for water from external sources, we do know how to waterproof structures. (Heck, my basement, whose floor is about 5' underground, is so dry I need a humidifier to keep the books I store down there from dry-rotting--in Baltimore on a concrete slab with cinderblock foundations laid in 1937.)

        Re quakes: Best solution here is not to site the reactors near active fault lines or a large body of water (which it doesn't need) & move the power via HVDC lines; but if needs must, you quake-proof the installation. Even with a reprocessing loop a MSR would be much smaller & lighter than a LWR of comparable output & amenable to the sort of quake-proofing that's been done for many years.

        Re helium shortages: (1) "Closed cycle" = "reuse indefinitely". It's only a means of transferring heat to a turbine; it doesn't get used up. (2) A nuclear reactor generates helium as a byproduct of alpha decay (which FTR is the source of practically all terrestrial helium, which shows up in natural gas via long-lived radioactive elements like thorium & uranium). That can be recovered in the reprocessing loop. Not sure how much it is, but it's something. (3) If the Feds stopped selling off the national helium reserve at rock-bottom prices & allowed the market to dictate its cost, natural-gas producers would find it practicable to recover it from their product.

        (Just FTR I know I'm not going to convince you--you'll ignore my arguments & throw one new objection after another at me. I'll keep replying so long as it's fun & I have the time.)


        by Uncle Cosmo on Fri Apr 05, 2013 at 10:48:48 AM PDT

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