On Fri, Nov 15, 2013 at 4:19 PM, Russell Standish <li...@hpcoders.com.au>wrote:
> For all the arguments pro and con nuclear fission, including an > impassioned speech by a 16 year old last night to a UN Youth Voice > competition, what never seems to be discussed is the elephant in the > room of how much uranium resources we have.IIUC, if all fossil fuel > power plants were replaced by conventional fission reactors, we'd burn > through our uranium supplies in about 50 years flat. I don't know where you got that figure, I suspect that long ago in a galaxy far far away some tree hugger pulled it out of his ass and then repeated it so often on the internet that people started treating it as fact. At any rate if we're running out it's hard to figure out why today Uranium prices are the lowest they've been in 8 years. > So fission reactors do not solve the problem. Of course there is fast > breeder technology, but everbody is so shit scared about all the plutonium > that would then appear on the market, making it incredibly easy for rogue > states to construct nuclear weapons Uranium fast breeder scare the shit out of me too and for the same reason, I don't like Plutonium. But I do like Thorium reactors, in particular Liquid Fluoride Thorium Reactors (LFTR) . I think LFTR's are what fusion wanted to be but never achieved, despite tens of billions of dollars poured into it a fusion reactor has never produced one watt more power than was put into it. Certainly LFTR's are better than conventional nuclear fission. Consider the advantages: *Thorium is much more common than Uranium, almost twice as common as Tin in fact. And Thorium is easier to extract from its ore than Uranium. *A Thorium reactor burns up all the Thorium in it, 100%, so at current usage that element could supply our energy needs for many billions of years; A conventional light water reactor only burns .7% of the Uranium in it. We'll run out of Thorium in the Earth's crust about the same time that the sun will run out of Hydrogen. * To burn the remaining 99.3% of Uranium you'd have to use a exotic fast neutron breeder reactor, Thorium reactors use slow neutrons and so are inherently more stable because you have much more time to react if something goes wrong. Also breeders produce massive amounts of Plutonium which is a bad thing if you're worried about people making bombs. Thorium produces an insignificant amount of Plutonium. * Thorium does produce Uranium 233 and theoretically you could make a bomb out of that, but it would be contaminated with Uranium 232 which is a powerful gamma ray emitter which would make it suicidal to work with unless extraordinary precautions were taken, and even then the unexploded bomb would be so radioactive it would give away its presents if you tried to hide it, destroy its electronic firing circuits and degrade its chemical explosives. For these reasons even after 70 years no nation has a Uranium 233 bomb in its weapons inventory. *A Thorium reactor only produces about 1% as much waste as a conventional reactor and the stuff it does make is not as nasty, after about 5 years 87% of it would be safe and the remaining 13% in 300 years; a conventional reactor would take 100,000 years. *A Thorium reactor has an inherent safety feature, the fuel is in liquid form (Thorium dissolved in un-corrosive molten Fluoride salts) so if for whatever reason things get too hot the liquid expands and so the fuel gets less dense and the reaction slows down. *There is yet another fail safe device. At the bottom of the reactor is something called a "freeze plug", fans blow on it to freeze it solid, if things get too hot the plug melts and the liquid drains out into a holding tank and the reaction stops; also if all electronic controls die due to a loss of electrical power the fans will stop the plug will melt and the reaction will stop. *Thorium reactors work at much higher temperatures than conventional reactors so you have better energy efficiency; in fact they are so hot the waste heat could be used to desalinate sea water or generate hydrogen fuel from water. * Although the liquid Fluoride salt is very hot it is not under pressure so that makes the plumbing of the thing much easier, and even if you did get a leak it would not be the utter disaster it would be in a conventional reactor; that is also why the containment building in common light water reactors need to be so much larger than the reactor itself. With Thorium nothing is under pressure and there is no danger of a disastrous phase change so the expensive containment building can be made much more compact. John K Clark > that I don't see that happening > any time soon either. > > Cheers > > > -- > > > ---------------------------------------------------------------------------- > Prof Russell Standish Phone 0425 253119 (mobile) > Principal, High Performance Coders > Visiting Professor of Mathematics hpco...@hpcoders.com.au > University of New South Wales http://www.hpcoders.com.au > > ---------------------------------------------------------------------------- > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to everything-list+unsubscr...@googlegroups.com. > To post to this group, send email to everything-list@googlegroups.com. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/groups/opt_out. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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