Lately I’ve been seeing articles reassuring people that if there were a nuclear war, we could simply shelter in buildings, then shower and launder away any radioactive particles, and pop back into our regularly scheduled lives, none the worse. They remind me of Cold War propaganda and the duck-and-cover drills whose sole purpose was a public sense of security, yet these are on some reasonably reliable news sites, like NPR.
But let’s say I shelter indoors in an area outside the blast and heat zones. While I’m happily wash-wash-washing away that nasty nuclear dust, wouldn’t I inhale radioactive particles? And wouldn’t those potentially make me somewhat…dead? Or would the concentration be low enough that I’d be OK?
I should add that I’m not losing sleep over radioactivity but am puzzled by these glowing (sorry) accounts of nuclear survival.
If you are contaminated with dust containing alpha emitters only on your skin, then, yes - a thorough wash will deal with the problem. Alpha particles have little power of penetration and can be blocked easily.
Of course, if you happen to have inhaled or swallowed the aforesaid dust, things are much trickier.
In general, assuming that (1) you have reasonable protection for your nose and mouth and that (2) most of the contamination is in the form of dust with alpha emitters, then, yes, a thorough washing of yourself and the clothes you wore would be very helpful to greatly reduce exposure to radiation.
The damage from radioactive contamination is directly proportional to time of exposure, distance from the source, and the level of activity of the source. Washing off the contamination is intended to reduce the first two factors. Period.
Yes, you can certainly still end up suffering ill effects even if you do this. Not washing it off will be worse for you, though.
Also, inhaling or ingesting radioactive contamination is even worse than having it on your skin, because you are now exposed to any radioactive decay chains that produce alpha or beta particles (which are completely stopped by your skin in the case of the former, and partially stopped by your skin in the case of the latter).
While the dust is on your skin, you’re getting exposed to radiation, and it’s possible that that could have already given you cancer or something before it’s washed off. But the longer it stays on, the higher the risk of that, and so you will probably be OK if it’s washed off quickly.
More importantly, the longer the dust is on your skin, the more likely it is that some of it will make its way inside of you in some way. That’s much more likely to cause problems, because it’s probably mostly emitting alphas and betas.
The fallout becomes less radioactive as time passes … apparently fairly quickly from what I’ve been reading … down to 1% after two days ??? … that doesn’t sound right …
Except that that’s not actually an exponential decay; it’s a power law decay. The discrepancy would be because there are many different radioactive materials with many different half-lifes. At some point, though, that pattern would have to break down, when the only materials left are a few with very long half-lifes.
This surprised me … for some strange reason I thought fallout remained intensively radioactive for ten of thousands of years … I guess that’s what I get for learning all my nuclear physics from MST3K …
a lot of the common fission products (Strontium-90, Cesium-137, Iodine-131) are relatively short lived with half-lives measured in days to a couple dozen years. they’re dangerous for a few reasons; first because they tend to be a lot more radioactive than the materials used for fission (uranium, plutonium.) Second, because they can be biologically active and incredibly harmful if ingested. radioactive iodine gets taken up by the thyroid and can impair it or cause cancer. Strontium is in the same group as calcium, so any radioactive strontium which gets into your body can end up in your bones for a long time.
It is so, but to be effective you need a special brand of soap, Dr. Von Nonstein’s anti-radiological purifying Saponified Iodinic Glycerine Sunshine Bathing Bars, with Shea Butter.
Fortunately, I have some in my travel-case beside me, as I tour the great Mid-West, and I can let them go as a favor for only $22 a tablet, or by post add £20 each. No more than 40 per person.
The longer the half-life of an isotope, the less dangerous it is, because that means that the decays (which are what releases the radiation) happen less often. U-238, for instance, has a half-life of billions of years, and so it produces radiation only extremely slowly, and so is, practically speaking, pretty much safe (it’s bad to ingest it, but that’s more because it’s a toxic heavy metal than because it’s radioactive). U-235 isn’t much worse, aside from the quirk of what happens when you get enough of it concentrated enough.
On the other end of the scale, you also have some things with half-lifes of days or less. These are very nasty, while they last, but if you just wait a little while, they disappear. So they’re also not all that worrisome.
Where the real problem comes in is in between, with things that last a hundred years or so. That’s a long time to wait them out, but during that time they’re still plenty active.
Yet another poster, in this case the OP, unfairly bashing duck-and-cover.
Not everyone is at ground zero! Inside a certain zone you’re toast. Far enough away you’re okay. In between is a very large area where at the very least flopping to the ground can increase your chances of surviving and reduce the odds of getting hurt. Ducking under a desk, a blanket, etc. increases the odds.
Yes, the intensity of the radioactivity and the duration of the radioactivity have to be inversely correlated because that’s how radioactivity works.
When we say a substance is highly radioactive, what does that mean? It means that the nuclei in the substance are breaking down and emitting alpha, beta, and gamma particles. For a substance to be highly radioactive that has to happen a lot. But that means that the original radioactive source is being destroyed as it emits radiation. Isotopes with short half lives emit radiation quickly, but therefore they are gone quickly. And conversely, isotopes with long half lives last a long time, but that’s because they break down slowly and therefore only emit a small amount of radiation.
There are plenty of radioactive isotopes created in a nuclear blast that have half-lives of only hours or days. That means intense radiation in the first hours or days, but much less in the later hours or days.
And then there are the medium half life isotopes, like Polonium-210 with a half life of 138 days, or Cobalt-60 with a half life of 5 years. And the problem here is “medium amount of radiation over a medium amount of time”. With a short half-life isotope if you can avoid exposure for a short time the danger will be mostly gone. But it’s a lot harder to shelter from these medium level threats.