Interesting, can you point me to any sources that discuss those issues? On 15 June 2012 21:11, Axil Axil <[email protected]> wrote:
> Details, details, details… > > There are some fundamental political as well as technical problems with > the LFTR that take some of the luster off your high opinion of this > technology. > > One of the most insidious is the desire of the LFTR advocacy crowd to > require the use of 19.75% enriched U235 to perpetually provide the > supplemental neutrons needed to keep the thorium fuel cycle critical. Even > worst is the desire to use plutonium as the source of supplemental > neutrons. You can build bombs with reactor grade Plutonium as demonstrated > by some bomb tests in India and the USA. > > Then there is the need for U233 denaturing with U238 at a rate of 88%. > This produces lots of plutonium which is always a proliferation risk. > > The only way to get a PURE thorium fuel cycle is to use hot fusion is some > way in a hybrid to eliminate the need for uranium235 and plutonium. But the > LFTR advocates say that fusion is not viable. > > So currently a LFTR with a PURE thorium fuel cycle is a fantasy. > > > Cheers: Axil > On Fri, Jun 15, 2012 at 1:43 PM, Robert Lynn < > [email protected]> wrote: > >> >>> 1/ The power source is too diffuse, and the sun doesn't shine at night >>>> meaning you need a huge plant to produce significant power. >>>> >>> >>> This is 110 MW on 1,600 acres. That is excellent power density. Better >>> than uranium fission or coal, when you take into account the land needed >>> for the mines and railroads to transport the fuel. >>> >> >> 100MW/year is about 70kg of thorium in a LFTR (about 250 times less than >> a conventional non-breeding uranium reactor requires), at average 6ppm >> there is about 70kg of thorium in the accessible column of earth under >> every square meter of the earth's crust. Thorium deposits are of course >> far more concentrated, so you can see the mined land and infrastructure >> needed to produce 70kg of thorium per year are relatively tiny and the >> thorium itself is benign enough to delivered by a postman. LTFR waste >> decays below natural uranium radioactivity in 300 years. >> >> >>> 2/ You have to build mirrors heavy to survive weather/environment. >>>> Hail, snow, rain, salt, wind, dust and UV all mean that the construction >>>> needs to be reasonably heavy if you want it to survive decades even if the >>>> bad weather is infrequent. >>>> >>> >>> That has not been a problem with existing installations. The LUZ >>> installations have lasted for 30 years in a harsh environment. >>> >> >> The point is that existing CSP is heavy but the environment means that it >> can't be made much lighter to reduce costs. Each m² contains 10's of kg of >> expensive low iron and borosilicate glass, metals, plastics, paints, >> concrete, mirror controls, copper wiring, bearings, stainless steel heat >> piping, silver coatings etc and yet only delivers about 100W averaged over >> the year. All that material content and its processing is a large part of >> the reason that CSP is currently optimistically $4000/kW nameplate >> capacity, but at $0.05/kWh delivers only about $100 worth of electricity >> per year. >> >> >> >>> >>> >>>> 3/ The plants are a relatively long distance from consumers and >>>> existing grid infrastructure - expensive grid connections. >>>> >>> >>> That is a problem with some wind installations, but not a problem with >>> solar PV or CSP. The PV installations are being built right on the grounds >>> of gas turbine generators, giving the overall installation about 10% more >>> peak power. The Crescent Dunes installation is right next to a major high >>> voltage line so it will not cost any more than a conventional generator to >>> hook up. That's why they put it there. >>> >>> Solar is more flexible than wind. >>> >>> Most solar power in Japan is a couple of meters away from the people who >>> will use it, right on the roof. In southern Japan -- which resembles the >>> U.S. southwest only with lots more rain -- solar roofs are everywhere these >>> days. They do not generate much power on rainy days, but people do not need >>> much power on rainy days. >>> >>> >>>> 4/ There will be alternative extremely cheap sources of intense heat >>>> energy available for foreseeable future (fossil fuels + nuclear, probably >>>> LENR, maybe hot fusion). >>>> >>> >>> Nuclear is not cheap! Not after Fukushima. Fossil fuels are only cheap >>> because the power companies do not pay for the 20,000 they murder every >>> year, and they will not pay for the cost of global warming. Add in those >>> costs and coal or natural gas would cost FAR more than CSP. >>> >> >> That is ridiculous, every industry has a death toll and of course the >> fossil fuel industry pays for those lives, in insurance levies, higher >> salaries for dangerous jobs etc. But there are different standards in the >> West to the developing world where most of those deaths occur as life is >> not valued so highly. Coal is 15 deaths per TWh in USA, but almost 300 in >> China. Gas is just 4 per TWh worldwide (1 TWh is worth about $200 million >> at retail level). >> >> Nuclear is in global terms still extremely safe even after Fukushima and >> Chernobyl, and will be very cheap once perfected, but we are not there yet. >> The global nuclear plant development hiatus of the last 30 years hurt, and >> antiquated plants like fukushima have to go, but new build nuclear is >> <$2000/kW in China (targeting $1000/kW) and much much safer, with tiny fuel >> and operations costs. However it is still only a stop-gap until breeder >> reactors are developed to reduce waste and Thorium in particular offers >> huge gains in safety, waste minimisation and fuel efficiency that will all >> lead to big cost savings. If you are willing to assume favourable learning >> curves for CSP then you should be willing to do the same for nuclear. >> >> Without wanting to open another can of worms, not a whole lot of warming >> apparent in last 15 years, and falling rate of sea level rise since 2006. >> While the earth warmed in the 20th century and it seems most likely CO2 >> had some positive effect, the IPCC's assumed high positive H20 feedbacks >> were ill-founded and are now being steadily revised downwards. Even their >> "best-case" model predictions from 10 years ago have now been shown to be >> excessively pessimistic. Seems very likely that CO2 driven thermaggedon >> isn't as bad as was advertised. >> >> http://www.woodfortrees.org/plot/rss/from:1997/to:2013/plot/rss/from:1997/to:2013/trend >> >> http://climate4you.com/images/UnivColorado%20MeanSeaLevelSince1992%20With1yrRunningAverage.gif >> Given current temperature and seal level trends I'm content to have the >> earth climate change as we it may without political intervention for >> another few decades as we transition to nuclear or LENR for sound economic >> reasons without seeing the need for a gun to be held to our heads. >> >> >>> Given massive availability of shale gas produced electricity at >>>> $0.04-0.06/kWh (currently <$0.04/kWh in USA due to extremely low gas price) >>>> . . . >>>> >>> >>> That price does not include the cost of the land that is destroyed by >>> fraking. Add that in and we are paying a fortune and destroying our living >>> space, our wildlife and our future. >>> >> >>> If you burn the furniture in your house in winter to keep warm, you can >>> live cheaply for a month. Then what do you do? After we destroy large parts >>> of New York, Pennsylvania and West Virginia, where will we live? What will >>> we eat? >>> >> >> How about doing the frakking in uninhabited regions instead? US is not >> short of alternative gas resources. Sounds like either there is a problem >> with your democracy not functioning very well, or the land is not actually >> being destroyed or rendered uninhabitable as you claim so people are not >> voting against it. How exactly is land destroyed by frakking anyway? >> >> >>> >>> >>>> and the best CSP running along at $0.2-0.3/kWh, there is just no >>>> foreseeable technology path that can bring the CSP cost down by a factor of >>>> 4 to compete with gas and (eventually) nuclear. >>>> >>> >>> That's absurd. What is so expensive about making mirrors? Do you think >>> they cost far more than gas turbines? And what do you think coal >>> electricity would cost if 20,000 families every years successfully sued >>> them for murdering their fathers and mothers? As I said here before, if the >>> airlines killed 20,000 people in one year, the entire aviation industry >>> would be closed down, and we would soon have high speed trains instead. The >>> only reason that does not happen with coal fired electricity is because the >>> victims are poor people living downwind of the generators. They do not vote >>> and they cannot afford to file suits, so you can kill them off with >>> impunity. No one but his family gives a damn when a poor person dies at age >>> 60 instead of 70 or 80. >>> >> >> Yes, CSP mirrors are demonstrably far more expensive than gas turbines. >> $300/kW for the glass alone ($30/m², need about 10m² for 1kW 24 hours per >> day), without all the other fabrication, installation, thermal plant, land, >> etc. The CSP mirror industry has already had the opportunity to travel far >> down the learning curve, being not much different from mass producing >> window glass (though the materials are a little different, particularly >> low-iron and expensive borosilicateglass) but are not reducing cost >> significantly. >> >> I'm all for getting rid of coal for power, it should at most be a >> feedstock for metals and chemicals. Coal is rapidly being supplanted by >> gas anyway, that more than halves CO2 for the same power output. It also >> produces far fewer noxious emissions (though why would you put up with >> dirty coal stacks when tech exists to clean them up - poor democracy or are >> we talking developing world again?) >> >> >
