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Comment by petre | Hacker News Reader

> total catastrophic destruction of the environment for (tens of) thousands of years

More like 300 years (10 Cs137 and Sr99 half lives) but otherwise you're right.

Plutonium, a byproduct of all nuclear reactors and part of their waste stream, is dangerous for 240,000 years.

How much plutonium is likely to be released in a nuclear incident? I thought Three Mile Island and Chernobyl mostly released radioactive isotopes of iodine and a bunch of noble gasses, with cesium, plutonium, and strontium being present in smaller quantities and generally settling closer to the reactor.

Where did you get that number?

Seems like a typo. Half-life of Pu-239 is ~24,000 years, and of Pu-242 ~374,000 years.

I'm guessing Pu-239 was intended as 1) an extra "0" digit is the more likely typo, and 2) Pu-239 is (AFAIU) the principal Plutonium byproduct of typical Uranium fission reactors.

Half life means that radioactivity is reduced by half, not eliminated. A single particle of plutonium is enough to cause cancer and kill a person. This is why nuclear fuel rod storage (the waste products) must be guarded for hundreds of thousands of years.

Half life is inversely proportional to radioactivity. Hundreds of thousands of years = no worries, you only live up to 1e-3 that amount.

Not all reactors; fast neutron burner reactors output less Pu than they consume.

Those exist only on paper. I'm speaking of actual production reactors which create dangerous amounts of plutonium-laden waste that needs to be cooled, monitored, and protected from human intervention for hundreds of thousands of years -- a problem that we still have no way to solve.

Plutonium release is far less being less mobile and it doesn't have the biological issues strontium does.

Well, it depends, if you're at 10 times the safe level, you will need far more than the half life.

Most likely between 900 and 1200 years.

10 half lives = QTY/1024. Not one half life. At Chernobyl one half life has already passed.

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