Thorium: The Wonder Fuel That Wasn't 204
Lasrick (2629253) writes "Bob Alvarez has a terrific article on the history and realities of thorium as an energy fuel: For 50 years the US has tried to develop thorium as an energy source for nuclear reactors, and that effort has mostly failed. Besides the extraordinary costs involved, In the process of pursuing thorium-based reactors a fair amount of uranium 233 has been created, and 96 kilograms of the stuff (enough to fuel 12 nuclear weapons) is now missing from the US national inventory. On top of that, the federal government is attempting to force Nevada into accepting a bunch of the uranium 233, as is, for disposal in a landfill (the Nevada Nuclear Security Site). 'Because such disposal would violate the agency's formal safeguards and radioactive waste disposal requirements, the Energy Department changed those rules, which it can do without public notification or comment. Never before has the agency or its predecessors taken steps to deliberately dump a large amount of highly concentrated fissile material in a landfill, an action that violates international standards and norms.'"
Sihg... Not valid. (Score:5, Informative)
Thorium when used as a reactor fuel does not involve separating the U 233 from the spent fuel. A small amount of 233 can be used to start the reaction but you burn the 233 in the reactor fuel that breeds it. It is also full of FUD.
"The last serious attempt to use thorium in a commercial reactor was at the Fort St. Vrain plant in Colorado, which closed in 1989 after 10 years and hundreds of equipment failures, leaks, and fuel failures."
The problems had nothing to do with the use of thorium fuel. It had everything to do with a badly designed cooling system that used He instead of water.
I just not have time to shred it but it is just terrible FUD! Look up the Fort St. Vrain reactor yourself to see the reports on the problems with the He system. They used bad water seals that leaked into the cooling circuit that caused the problems.
In other words this article has nothing really to do with the Thorium reactors that are being proposed today. Not surprising since samzenpus is know to be anti-nuclear.
Re:Is this about Thorium or Uranium 233? (Score:5, Informative)
Thorium 232 + a neutron -> Uranium 233.
Note that the "United States produced, over the course of the Cold War, approximately 2 metric tons of uranium-233, in varying levels of chemical and isotopic purity" (from Wikipedia [wikipedia.org]. As best as I can tell from the BAS article, the missing U-233 is from "the Oak Ridge National Laboratory, the Rocky Flats nuclear weapons facility, and the Idaho National Laboratory" - i.e., it was weapons production related U-233, not stuff from a thorium breeder program, and probably a problem of bad book-keeping, not an actual loss of material.
Note that U233 is going to be highly radioactive, due to unavoidable U232 impurities, and will be such a strong emitter of gamma rays that this "makes manual handling in a glove box with only light shielding (as commonly done with plutonium) too hazardous." That, plus a failure to ever produce a non-fizzle U233 bomb, means that this really isn't a good fission bomb source material.
All in all, I actually expect better from the Bulletin of the Atomic Scientists.
Landfill? (Score:5, Informative)
On top of that, the federal government is attempting to force Nevada into accepting a bunch of the uranium 233, as is, for disposal in a landfill (the Nevada Nuclear Security Site).
http://www2.nstec.com/Pages/in... [nstec.com]
This isn't some hole in the ground full of coffee grounds and soiled nappies.
"50 years" (Score:5, Informative)
For 50 years the US has tried to develop thorium as an energy source for nuclear reactors, and that effort has mostly failed.
Actually, it really hasn't.
It experimented for 10-15 years with thorium, early in the history of the nuclear age, until it was established that you can't really make a lot of bombs from the by-products of thorium reactors. And then it moved funding toward uranium-based systems.
There hasn't been much meaningful research into it since about 1969, when ORNL shut down its MSRE.
It'd probably be worth setting up a few not-too-large reactors just so we can burn up some of the nuclear "waste" (read: 'unused fuel) from the current uranium-based reactors.
Real Reasons Thorium is Being Held Up (Score:5, Informative)
1) The liquid medium that is actually containing the fission events is incredibly caustic. This means that the reactor vessel, in addition to dealing with a very high neutron flux, has to handle severe corrosion issues at the surface. The fact that it is done at STP does not provide any help. 2) The salt 'plug' that is often cited as a major safety asset for the LFTR has some major engineering obstacles that have been be able to be addressed yet. 3) The liquid medium has to undergo re-processing on a fairly frequent basis. This is non-trivial as the medium is highly caustic and radioactive. The products pulled out are also highly problematic. This is probably one of the biggest hurtles for LFTR. It is a costly and messy chemical process.
There are other smaller problems, but these are the 'big three' I can recall.
For next-gen reactor tech my money is either on traveling wave type reactors (which never need to be refueled for its entire lifespan..30-100 years). Look up the Toshiba 4s for the furthest along reactor.
There are also sub-critical 'energy amplifier' reactors that use a particle accelerator to drive a proton beam into a spallation target (lead) which causes a neutron flux suitable for fission events to occur, though not enough to cause a self-sustaining reaction. Only 10% of the energy is required to be redirected back to the accelerator (fission rules like that). This one has the advantage of being able to use pretty much any fuel, and waste we have as well as reducing the daughter products to benign isotopes. Belgium is currently in the process of building one.