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Thorium, the Next Nuclear Fuel?
mrshermanoaks writes "When the choices for developing nuclear energy were being made, we went with uranium because it had the byproduct of producing plutonium that could be weaponized. But thorium is safer and easier to work with, and may cause a lot fewer headaches. 'It's abundant — the US has at least 175,000 tons of the stuff — and doesn't require costly processing. It is also extraordinarily efficient as a nuclear fuel. As it decays in a reactor core, its byproducts produce more neutrons per collision than conventional fuel. The more neutrons per collision, the more energy generated, the less total fuel consumed, and the less radioactive nastiness left behind. Even better, Weinberg realized that you could use thorium in an entirely new kind of reactor, one that would have zero risk of meltdown. The design is based on the lab's finding that thorium dissolves in hot liquid fluoride salts. This fission soup is poured into tubes in the core of the reactor, where the nuclear chain reaction — the billiard balls colliding — happens. The system makes the reactor self-regulating: When the soup gets too hot it expands and flows out of the tubes — slowing fission and eliminating the possibility of another Chernobyl. Any actinide can work in this method, but thorium is particularly well suited because it is so efficient at the high temperatures at which fission occurs in the soup.' So why are we not building these reactors?"
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.[21] 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.[22] 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.[23] India currently envisages meeting 30% of its electricity demand through thorium-based reactors by 2050.[24]
Of course, if we're going to tackle the problems of the 21st Century, we have to be willing to solve hard engineering problems, but it makes perfect sense to tackle the easier ones first. Especially when it takes years to build and test a reactor, so developing anything really new is apt to take a decade or two before it can actually make money. So far, it has always seemed easier to tweak the existing, mature Uranium technology to deal with its remaining problems.
Personally, I'd love to see a sustained government effort to develop commercially viable Thorium power plants. (I have thought this since the 1970s.) But the reason that hasn't happened yet is Thorium just has too many unsolved problems -- it's not because of some industry conspiracy.
--Greg
Not true.
This is part of why the whole quasi-conspiratorial story of "why we didn't go with thorium in the first place" is utter nonsense. It was not because "we wanted bombs instead" and were prejudiced against "superior thorium", it is because only if you have an established nuclear industry cranking out materials usable in bombs by the thousands can you build these reactors in the first place. Either you must have natural/low enriched uranium reactors to produce plutonium, or you need large amounts of highly enriched uranium (prime bomb material) to load into thorium breeders.
Also unacknowledged is that the particular type of reactor being promoted, the molten fluoride salt reactor, was and is a complex technology that requires substantial additional development. Only one single reactor of this kind was ever built, and it was an 8 megawatt (thermal) materials test reactor, not a power reactor. We are looking at many years of additional development before construction can start on a prototype full scale power reactor. I agree that this technology should be further pursued, and it may turn out more successful that plutonium breeders (no successful power plants have been built, just several failures) but it is by no means guaranteed.
Hyman Rickover, by the way, was interested in light water uranium fueled reactors because they are a good technology for powering submarines, not because they produce plutonium (they are lousy plutonium producers, the yield is low and the material produced has terrible properties for bombs).
Check out the 2005 IAEA survey document (http://www.energyfromthorium.com/pdf/IAEA-TECDOC-1450.pdf) for a good summary of the thorium technology options and prospects.
Starships were meant to fly, Hands up and touch the sky - Nicky Minaj
By most accounts, a functional prototype reactor is 20 years away.
The designer of the molten salt Thorium reactors ran his reactor non-stop for over 10 years IIRC. This was in the 1960s. What is unproven exactly?
Extracting thorium from the ground is harder than for uranium,
Which we will run out of in 10 years.
Thorium will also produce dangerous, radioactive by products,
And Uranium produces candy canes and puppies? If Thorium really is harder to refine or weaponize than Uranium, we'd be better off switching to Thorium, so you contradict yourself.
Also, Thorium reactions do not produce plutonium. The fact that Thorium reactions do not produce weaponized by products is one of its huge advantages, above and beyond its abundance and higher efficiency as nuclear fuel when compared to Uranium.
Higher Logics: where programming meets science.
The "uses more carbon to produce than it saves in its lifetime" charge is a persistent myth. It seems just "shocking" enough to be true, and happens to coincide with what many rich interests would like to be true. As a result, it comes up quite often in non-fact-centric talk shows and as a result is something that a lot of people just "know". Unfortunately, it's just not true.
I have researched this and haven't been able to find a time when it was EVER true, but it certainly isn't true of either modern solar cells (even in small-scale deployments) or wind turbines. Moreover, as the general power supply becomes "greener", the carbon footprint for manufacturing (a huge portion of which comes from the energy needed to produce, not raw materials) also declines.
Example calculation for mid-size (office building) solar deployment: http://greenestofthegreen.wordpress.com/2008/09/08/solar-panels-the-smallest-footprint/
- Calculates a carbon break-even point of 15 months, for a product expected to last for 25 years on the inside.
- Obviously comes from the company making these, so take it with a grain of salt, but it's not likely to be off by the order of magnitude or more needed to make your statement true.
I can't find similar calculations for wind turbines fro a quick Google search, but the return on carbon "investment" there is shorter-term (assuming a windy area and fairly large-scale deployment of multiple wind turbines in a pass). If you have a citable reference stating otherwise, please share it with the class.