Nuclear Power — Reprocessing

I have been receiving a set of questions on nuclear power. I will be answering them over time in this space.

The danger of reprocessed fuel is nuclear proliferation in countries that don’t already have the bomb. Basically, reprocessing takes nuclear waste, and separates out the highly radioactive fission products, the small atoms. The uranium and transuranic elements are not very radioactive, and that portion is now safe to steal.

The plutonium in reprocessed fuel is contaminated with a large amount of Pu-240, while military grade plutonium is more than 93% Pu-239. Every country that uses plutonium to make bombs has a special reactor to make Pu-239, and all designs of bombs that have been tested use Pu-239. However, bomb specialists believe that a bomb, not very good, could be made with the contaminated plutonium, though estimates about the amount of fuel one would need are classified (as they are for bombs that have been built with military grade plutonium). The problem with too much Pu-240 is that it has a high rate of spontaneous fissions, producing neutrons. When these neutrons hit the plutonium fuel, “pre-initiation” may occur.

For a functional country, it’s easier and cheaper and more reliable to make the Pu-239, but for a dysfunctional country or a non-government, stealing may be easier. Overwhelmingly the best to steal, of course, is loose Russian nuclear weapons material. Perhaps second is stealing reprocessed fuel (not sure), if there were any reprocessing plants in countries with a loose rule of law.

The United States stopped reprocessing under Carter to “set a good example” for other countries, but neither France nor Britain, the other countries, stopped reprocessing. Additionally, US scientists believed it cheaper to toss used fuel into the ground than to reprocess. I don’t know how much this calculation has been affected by the protest (not based on the facts) of using Yucca Mountain as a permanent repository, or by technology improvements, but some US scientists are now seeing reprocessing as more attractive.

Update I have no opinion yet on whether reprocessing is a good option for the United States. I am waiting for the various arguments being made in the science and policy community to sort out better in my head, or even better, among the people studying it. I have read enough to understand why people in policy promote nuclear power as one of the solutions.

For those who want to read more, I highly recommend David Bodansky Nuclear Energy Second Edition.

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