Posted on 09/01/2010 8:13:28 AM PDT by Wurlitzer
Thanks for your interest and contribution.
From: http://thoriumsingapore.com/content/index.php?option=com_content&view=article&id=57&Itemid=57
4. Operability and reliability. The LFR can be refueled continuously and easily while online, which would improve the competitiveness of utilities by eliminating refueling shutdowns. The composition of the salt is continuously re-homogenized by pumping the salt through the core. There are no “hot channels” or local burnup in a liquid-fluoride core due to this action, and not need for fuel reshuffling. Fuel can be removed easily by draining the core. The strong negative temperature coefficient allows the reactor to “follow the load” without operator intervention, and to reduce power generation extremely rapidly in response to “loss of load” accidents.
http://www.freerepublic.com/focus/f-news/1470290/posts
http://www.freerepublic.com/focus/f-bloggers/2099414/posts
http://www.freerepublic.com/focus/f-news/2530550/posts
I was actually just studing this past weekend about it... seems like a no brainer. which means it will never happen..
Thanks for the lead. It does appear India is doing something with thorium according to this Wikipedia article:
“India’s Kakrapar-1 reactor is the world’s first reactor which uses thorium rather than depleted uranium to achieve power flattening across the reactor core.[25] India, which has about 25% of the world’s thorium reserves, is developing a 300 MW prototype of a thorium-based Advanced Heavy Water Reactor (AHWR). The prototype is expected to be fully operational by 2011, following which five more reactors will be constructed.[26] Considered to be a global leader in thorium-based fuel, India’s new thorium reactor is a fast-breeder reactor and uses a plutonium core rather than an accelerator to produce neutrons. As accelerator-based systems can operate at sub-criticality they could be developed too, but that would require more research.[27] India currently envisages meeting 30% of its electricity demand through thorium-based reactors by 2050.[28]”
Apparently their reactors still need plutonium.
Sorry if I sound flippant, but back in the 1950s when nuclear energy came on line, people were predicting that all homes would have their own mini nuclear reactor and electricity would be "too cheap to meter". How wrong they were then, and I suspect this will turn out to be the same.
My comment is that if something appears to be too good to be true, it usually is.
Something for the ecofreaks to chew on (you know them any technology is bad unless they say so and even then don’t build it in their back yard.).
from: http://thoriumsingapore.com/content/index.php?option=com_content&view=article&id=52&Itemid=50
In fact non-nuclear systems like coal spew out worse pollutants. The emissions from those contain arsenic, mercury, lead and a whole host of radioactive materials like uranium, thorium and radium dumped directly into the environment at levels 100 to 400 times the level of nuclear plants!
Lighten up Francis.
“My comment is that if something appears to be too good to be true, it usually is”
FartherofFive: True, true, true and that is why I posted it on FR as we have many here who can find the flaws in just about anything if it is flawed.
If there is something in the literature that is false, lets dig it out otherwise I think we need to push our various representatives as this could make us energy independent in almost every non-moving vehicle area.
Gives me more reading to do.
“Lighten up Francis.” Huh?
seems to be something worth pursuing... but alas i dream on... India,China will make much better use of this then the silly Americans...
More waste related info:
A liquid-fluoride thorium reactor (LFTR) makes ~0.08% of the waste per GW-yr of a regular LWR and other traditional nuclear power plants.
All Thorium reactors need a neutron source. Thorium by itself is not a nuclear fuel.
Thorium, as well as uranium, can be used as a nuclear fuel. Although not fissile itself, Th-232 will absorb slow neutrons to produce uranium-233 (U-233), which is fissile (and long-lived). The irradiated fuel can then be unloaded from the reactor, the U-233 separated from the thorium, and fed back into another reactor as part of a closed fuel cycle. Alternatively, U-233 can be bred from thorium in a blanket, the U-233 separated, and then fed into the core.
In one significant respect U-233 is better than uranium-235 and plutonium-239, because of its higher neutron yield per neutron absorbed. Given a start with some other fissile material (U-233, U-235 or Pu-239) as a driver, a breeding cycle similar to but more efficient than that with U-238 and plutonium (in normal, slow neutron reactors) can be set up. (The driver fuels provide all the neutrons initially, but are progressively supplemented by U-233 as it forms from the thorium.) However, there are also features of the neutron economy which counter this advantage. In particular the intermediate product protactinium-233 (Pa-233) is a neutron absorber which diminishes U-233 yield.
http://world-nuclear.org/info/inf62.html
...has anyone actually built and operated a thorium reactor?
- - - -
Between 1967 and 1988, the AVR (Atom Versuchs Reaktor, Nuclear Test Reactor) experimental pebble bed reactor at Jülich, Germany, operated for over 750 weeks at 15 MWe, about 95% of the time with thorium-based fuel. The fuel used consisted of about 100,000 billiard ball-sized fuel elements. Overall a total of 1360 kg of thorium was used, mixed with high-enriched uranium (HEU). Burn-ups of 150,000 MWd/t were achieved.
Thorium fuel elements with a 10:1 Th/U (HEU) ratio were irradiated in the 20 MWth Dragon reactor at Winfrith, UK, for 741 full power days. Dragon was run as an OECD/Euratom cooperation project, involving Austria, Denmark, Sweden, Norway and Switzerland in addition to the UK, from 1964 to 1973. The Th/U fuel was used to ‘breed and feed’, so that the U-233 formed replaced the U-235 at about the same rate, and fuel could be left in the reactor for about six years.
General Atomics’ Peach Bottom high-temperature, graphite-moderated, helium-cooled reactor in the USA operated between 1967 and 1974 at 110 MWth, using high-enriched uranium with thorium.
In Canada, AECL has more than 50 years experience with thorium-based fuels, including burn-up to 47 GWd/t. Some 25 tests were performed to 1987 in three research reactors and one pre-commercial reactor (NPD), with fuels ranging from ThO2 to that with 30% UO2, though most were with 1-3% UO2, the U being high-enriched.
In India, the Kamini 30 kWth experimental neutron-source research reactor using U-233, recovered from ThO2 fuel irradiated in another reactor, started up in 1996 near Kalpakkam. The reactor was built adjacent to the 40 MWt Fast Breeder Test Reactor, in which the ThO2 is irradiated.
In the Netherlands, an aqueous homogenous suspension reactor operated at 1MWth for three years in the mid-1970s. The HEU/Th fuel was circulated in solution and reprocessing occurred continuously to remove fission products, resulting in a high conversion rate to U-233.
The 300 MWe THTR (Thorium High Temperature Reactor) reactor in Germany was developed from the AVR and operated between 1983 and 1989 with 674,000 pebbles, over half containing Th/HEU fuel (the rest graphite moderator and some neutron absorbers). These were continuously recycled on load and on average the fuel passed six times through the core.
The Fort St Vrain reactor was the only commercial thorium-fuelled nuclear plant in the USA, also developed from the AVR in Germany, and operated 1976-1989. It was a high-temperature (700°C), graphite-moderated, helium-cooled reactor with a Th/HEU fuel designed to operate at 842 MWth (330 MWe). The fuel was in microspheres of thorium carbide and Th/U-235 carbide coated with silicon oxide and pyrolytic carbon to retain fission products. It was arranged in hexagonal columns (’prisms’) rather than as pebbles. Almost 25 tonnes of thorium was used in fuel for the reactor, and this achieved 170,000 MWd/t burn-up.
Thorium-based fuel for PWRs was investigated at the Shippingport reactor in the USA.
In India, thorium has been used for power flattening in the initial cores of the two Kakrapar pressurised heavy water reactors (PHWRs).
The 60 MWe Lingen Boiling Water Reactor (BWR) in Germany utilised Th/Pu-based fuel test elements.
http://world-nuclear.org/info/inf62.html
Good question: In my reading last night I saw 2 US based proof of concept reactors which had been built, refueled, and deliberately forced to overheat to test the proposed method of disabling the reactor with NO human intervention.
The reactor shut it self down by heating a freeze type plug and letting the core liquid (the fuel is in liquid form at operating temperature) drain into a lower pit which is just cooled by the surrounding environment and the liquid recrystallized and the reaction was stopped cold.
Reheating the crystallized fuel and pumping it back into the core restored the reactor with zero damage other than replacing the freeze plug.
Thanks thackney for your detailed contribution. Good information.
The guys point was that this is another pipe dream that will not happen in this country.
..and Peak Oil....
Nuclear reactors using Thorium as fuel have already been built and put in operation in the US.
See info posted above.
I got that mad, and to a point I agree but being good conservatives as we are, we should not let our government or a coalition of government and business stop this technology IF it meets the hype.
Thanks,
Would you be willing to write letters of support for this technology to your individual reps and senators.
How about letters to various networks, newspapers (they still print those right?)?
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