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New NRC Rule Supports Indefinite Storage of Nuclear Waste
mdsolar writes in with news about a NRC rule on how long nuclear waste can be stored on-site after a reactor has shut down. The five-member board that oversees the Nuclear Regulatory Commission on Tuesday voted to end a two-year moratorium on issuing new power plant licenses. The moratorium was in response to a June 2012 decision issued by the U.S. Court of Appeals for the District of Columbia that ordered the NRC to consider the possibility that the federal government may never take possession of the nearly 70,000 metric tons of spent nuclear fuel stored at power plant sites scattered around the country. In addition to lifting the moratorium, the five-member board also approved guidance replacing the Waste Confidence Rule. "The previous Waste Confidence Rule determined that spent fuel could be safely stored on site for at least 60 years after a plant permanently ceased operations," said Neil Sheehan, spokesman for the NRC. In the new standard, Continued Storage of Spent Nuclear Fuel Rule, NRC staff members reassessed three timeframes for the storage of spent fuel — 60 years, 100 years and indefinitely.
Both of you need to read the Wikipedia page about nuclear fuels, as it says something surprising: there is a window in half lives, that is the half lives are either less than ten years, or more than a couple hundred years, or something along those lines. So the decay profile of half lives is not continuous, you have some very hot and dangerous stuff, but that also blows out its punch relatively fast, and relatively mild and less dangerous stuff, but that takes a couple hundred thousand years to go away. (As in, you might almost be willing live next to it, but you don't want to ingest it for sure. There are things like cinnabar minerals in nature, that you don't want to ingest, or arsenic minerals, also toxic mushrooms, but might be willing to coexist with, and live next to them.) So these days the protocol is to hold spent nuclear fuel on site for the less than ten years part, and then when that's gone, all you got is the very low radiating but extremely long half life stuff left, which is kinda safe to ship around by rail and store. But indeed, the stuff fresh out of the reactor is deadly, and needs to be aged on site to give out its punch first. If you read up on the Fukushima disaster on Wikipedia, you'll see mention of such aging ponds.
I'm quite aware of how radiotoxicity of spent nuclear fuel works. There are in fact graphs detailing it. Fast reactors and actinide burners prevent the actinides from entering the waste stream in the first place, hence why their waste is below original uranium ore radiotoxicity levels after a few hundred years. After that, you can essentially throw the stuff back into the pit you got it out of, knowing that you've actually lowered the overall radiotoxicity of the original material. For current LWRs on a once-through cycle this doesn't occur until some hundreds of thousands of years in the future.