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?) > >
