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Dilution is the solution to pollution. For radioactive isotopes with moderate half lives (that are not produced industrially in serious abundance), this actual

Dilution is the solution to pollution. For radioactive isotopes with moderate half lives (that are not produced industrially in serious abundance), this actually works.

phkahler 7y ago
Seems reasonable for individual incidents. Distribution into the environment on an industrial scale would be something quite different.
mirimir 7y ago
With dilution, for ~rapidly decaying isotopes, nobody arguably gets more than a de minimis dose. Comparable to a chest X-ray, transcontinental flight, etc. But that doesn't work for isotopes that bioaccumulate, and get concentrated up the food chain. Especially if that happens faster than radioactive decay. A good example is plutonium production. Back in the 40s-60s, they'd dissolve irradiated uranium in nitric acid. With remote manipulators, behind massive steel/lead/concrete shielding. But two of the major fission fragments are gases at processing temperatures: Xe-131 and I-131. So they just blew that up the stacks. Xe-131 stable, but inert, so dilution is arguably OK. Although the I-131 half-life is only ~8 days, animals bioaccumulate it very effectively. Also, it's concentrated in milk. In designing Hanford, scientists did a risk assessment for I-131 releases. They got that releasing I-131 was risky when the wind was blowing westward, toward coastal cities. But when the wind was blowing eastward, no problem. Especially because, for commercial milk production, delay from deposition on fodder to milk sales is (as I recall) on the order of weeks. However, they didn't consider subsistence farmers living around Hanford, raising cattle and goats for milk. For them, delay from deposition on fodder to milk consumption is on the order of days. Oops. So a bunch of people (mainly children) developed thyroid disorders and cancer. I could tell a similar story about radioisotope releases from above-ground testing. Which increased incidence of thyroid disorders and cancer throughout the US. But I'll just share the false assumption. Nuclear explosions inject crap into the lower stratosphere. Where it floats, just above the stratopause, driven by the jet stream. So there's not much dilution, just movement. And then, somewhere, there's an intense thunderstorm, which punches convection into the lower stratosphere. If that happens to intersect a mass of radioactive crap, it comes down right there. Almost as if the explosion had occurred right overhead. Who would have thought? If you're interested, you can find maps online that show deposition patterns for all of the above-ground test series.

Dilution is the solution to pollution. For radioactive isotopes with moderate half lives (that are not produced industrially in serious abundance), this actually works.

phkahler 7y ago

Seems reasonable for individual incidents. Distribution into the environment on an industrial scale would be something quite different.

mirimir 7y ago

With dilution, for ~rapidly decaying isotopes, nobody arguably gets more than a de minimis dose. Comparable to a chest X-ray, transcontinental flight, etc. But that doesn't work for isotopes that bioaccumulate, and get concentrated up the food chain. Especially if that happens faster than radioactive decay. A good example is plutonium production. Back in the 40s-60s, they'd dissolve irradiated uranium in nitric acid. With remote manipulators, behind massive steel/lead/concrete shielding. But two of the major fission fragments are gases at processing temperatures: Xe-131 and I-131. So they just blew that up the stacks. Xe-131 stable, but inert, so dilution is arguably OK. Although the I-131 half-life is only ~8 days, animals bioaccumulate it very effectively. Also, it's concentrated in milk. In designing Hanford, scientists did a risk assessment for I-131 releases. They got that releasing I-131 was risky when the wind was blowing westward, toward coastal cities. But when the wind was blowing eastward, no problem. Especially because, for commercial milk production, delay from deposition on fodder to milk sales is (as I recall) on the order of weeks. However, they didn't consider subsistence farmers living around Hanford, raising cattle and goats for milk. For them, delay from deposition on fodder to milk consumption is on the order of days. Oops. So a bunch of people (mainly children) developed thyroid disorders and cancer. I could tell a similar story about radioisotope releases from above-ground testing. Which increased incidence of thyroid disorders and cancer throughout the US. But I'll just share the false assumption. Nuclear explosions inject crap into the lower stratosphere. Where it floats, just above the stratopause, driven by the jet stream. So there's not much dilution, just movement. And then, somewhere, there's an intense thunderstorm, which punches convection into the lower stratosphere. If that happens to intersect a mass of radioactive crap, it comes down right there. Almost as if the explosion had occurred right overhead. Who would have thought? If you're interested, you can find maps online that show deposition patterns for all of the above-ground test series.