| The more radioactive something is, the shorter the half-life. High-level nuclear waste from spent fuel rods has three components: - U-238: less radioactive than uranium ore, makes up most of the waste. Only a problem because of all the other stuff that's mixed in with it. - Transuranics, mainly plutonium: radioactive for millennia. About 3% of the waste. - Fission products: the broken-up atoms. The most troublesome are radioactive for decades. About 1% of the waste. Since they have fairly short half-lives, they're the most radioactive. So it's the fission products which make lots of decay heat and have to be kept cool, but that heat production goes away fairly quickly. It's the transuranics that have to be stored for millennia, but they don't need cooling; since they have long half-lives they don't generate much heat. However, the U-238 and transuranics could be used as a fuel in more advanced reactors, either fast reactors or molten salt reactors. So actually we only need to store that waste until the more advanced reactors become available. In the article Thiel advocates pursuing new reactor types, including those that can eliminate long-term waste. If we do that, we'll end up with less long-term waste than we have right now. |