Start off with http://en.wikipedia.org/wiki/Thorium_fuel_cycle
if you need more just ask. On Fri, Jun 15, 2012 at 7:44 PM, Robert Lynn <robert.gulliver.l...@gmail.com > wrote: > Interesting, can you point me to any sources that discuss those issues? > > > On 15 June 2012 21:11, Axil Axil <janap...@gmail.com> 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 < >> robert.gulliver.l...@gmail.com> 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?) >>> >>> >> >
