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Pertho t1_j828dke wrote

Reply to comment by wonkozsane042 in Can the Radiation from a Sample of Depleted Uranium Sterilize? by Natolx

How long would someone need to be cryogenically frozen for cosmic radiation to be a significant threat? If it’s a couple lifetimes then I could still see people taking that gamble (not something I’m into myself, just enjoy learning about this). Could treatment before freezing with something like iodine or anti-radiant treatment reduce that danger?

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mfb- t1_j82iwi8 wrote

Iodine only protects the thyroid against radioactive isotopes of iodine. That's interesting after a nuclear explosion or a major power plant accident because Iodine-131 is a significant product of them, but it doesn't do anything otherwise.

> How long would someone need to be cryogenically frozen for cosmic radiation to be a significant threat?

A short-term dose of ~100 mSv is the lowest amount where we are sure it increases the cancer risk. If we assume accumulated dose during freezing acts like a short-term dose then we need ~200-300 years to get there. Damage from the freezing/thawing process is probably still your main concern here. If we look at doses so high that they can kill you short-term then we need over 1 Sv, or thousands of years. This is assuming no special shielding in any way, and it's also ignoring terrestrial radiation sources. Normally most of the radiation dose comes from that part and people get something like 2-3 mSv/year, so we would reach 100 mSv after 30-50 years or so and over 1 Sv after a few centuries.

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wonkozsane042 t1_j82vtiy wrote

mbf explains everything well. I will only add that I heard this in an online lecture (MIT graduate course on nuclear physics I believe) though the professor said he didn't actually do the calculation to determine how long that would actually take. But I would estimate it between 10000 to 100000 years factoring in all possible background radiation sources which corresponds to mbf's estimate. So maybe it's not as crazy as I was led to believe.

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