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First Superheavy Element Found In Nature
KentuckyFC writes "The first naturally occurring superheavy element has been found. An international team of scientists found several nuclei of unbibium in a sample of the naturally occurring heavy metal thorium. Unbibium has an atomic number of 122 and an atomic weight of 292. In general, very heavy elements tend to be unstable but scientists have long predicted that even heavier nuclei would be stable. The group that found unbibium in thorium say it has a half life in excess of 100 million years and an abundance of about 10^(-12) relative to thorium, which itself is about as abundant as lead." I'd also like it known that my spell checker did not know 'unbibium' before today, but it is now one word closer to encompassing all human knowledge.
Here's a link describing the Island of Stability
Neat stuff: apparently they've theorized a bunch of these super-heavy elements, they just haven't been observed yet (until now)!
There are two major issues with thorium in nuclear reactors.
Firstly thorium itself is not fissile, but Uranium-233 which can be created from it is. Using thorium for nuclear fuel therefore requires a breeder reactor and associated reprocessing. At the moment this is more expensive than using enriched uranium in light water reactors, but it may change if the costs of reprocessing decrease.
The second problem is the reprocessing itself. The Uranium made from thorium will contain traces of highly radioactive gamma emitters, and current reprocessing techniques are unable to adequately shield the workers from this radiation. There is also very little experience with thorium based reprocessing.
When it comes from nuclear proliferation thorium reactors would need safeguarding just as a conventional reactor would. The main reason is that while thorium itself is not usable in nuclear weapons, the Uranium-233 which is breed from it would be quite suitable. If that were to prove unfeasible it would also be possible to use a highly-enriched U-233 core surrounded by a U-238 breeder blanket to produce Pu-239, used in plutonium based weapons.
Basically if you are going to run a nuclear reactor you will need safeguards to prevent proliferation. This need not be a reason why we can't use nuclear power, it just means we shouldn't give the technology to every dictatorship on the planet that is willing to sign a piece of paper.
Thorium isn't fissile, so it's not just a matter of swapping U for Th.
Current fission reactors are based on same chain reaction that makes nuclear weapons work. Some people want to breed Th into U to keep using these reactor designs, but the cool thing about Th is that you can use it in a subcritical accelerator-driven system. This is a truly safe form of nuclear reactor - pull the plug and the reaction stops, no way that it can melt down. It can actually "burn off" nuclear waste. And because no plutonium is created and the mix of uranium isotopes it produces is hard to weaponize, it's proliferation resistant and not a terrorist target the way a conventional plant is. Thorium is much more abundant than uranium, and easier to mine and process.
If fission has a future, it's accelerator-driven systems. We ought to be putting our reasources toward funding the R&D needed to deploy them instead of building dirty and dangerous uranium or plutonium fission plants.
Tom Swiss | the infamous tms | my blog
You cannot wash away blood with blood