A reader writes:
So....At times things eat at my mind, it makes me good at some things, but at other times it just stresses me out. I thought you might have a point of view that would be reasonably sane on my dilemma. Though I acknowledge it's something that is far from your field of expertise, but you may have an idea... Just because radioactivity is cool.
So my flatmate visited Chernobyl. I thought that was kind of cool, but we somewhat agreed they'd discard their shoes and clothes afterwards (see where this is going? ;)
The tour got pretty close, they were standing within 100m of reactor 4. The digital Geiger counter was registering 4 mSv/h (I zoomed in on a photo.... will check that again at some point). Most of the tour group stayed on paved ground, though in some places quite broken. A few ignored the tour guides and were wandering around on the somewhat radioactive grass at one point near reactor 4. They ate at a nearby cafe, visited some of the local sites driving around in a small bus, then left the exclusion. On leaving they each went through some kind of radiation measuring device, it looked like a big metal arch, you put your hands on the sides of a console at head height and your face was pretty close to something, no one set that thing off. Though no one was really sure what it was measuring, or if your shoes were included.
Said flatmate spent another week travelling before returning to Australia, along with their Chernobyl clothes and shoes. The tour operators seem to think no special precautions needed to be taken with clothes and shoes after leaving.
Do you think particulate matter bought back poses a health risk worth worrying about? I made them leave their shoes outside the house....But on their clothes packed in the same bag as their shoes, it seems inevitable that some radioactive isotopes have made it inside. Though, they're only a problem if I inhale or digest them, damn cesium. I do acknowledge that I'm already host to unstable isotopes of carbon in measurable amounts.
I recently, fortuitously, bought a nice enough Miele vacuum cleaner which I hope effectively implements its HEPA filter.
Unfortunately I'm cynical enough about our own government's competence to have serious doubts as to whether the Ukrainian government has enforced effective safety procedures. Especially given the USSR's history at this site...
Roscoe
Summary, before I start talking about ways in which radiation can kill you horribly: Radiation is almost certain not to kill you horribly. Those clothes, especially the shoes, may be detectably contaminated, but they're very unlikely to be dangerously contaminated. And if they've been worn and washed a few times since the visit, contamination may not even be detectable any more. Even if you did big shoe-fetishist sniffs all over your flatmate's sneakers as soon as they got home, you'd probably still be at much greater risk from everyday non-radioactive air contamination.
Like you, I wouldn't have much faith in the dedication of Ukrainian Chernobyl-tour outfits to customer safety. Lord knows the Western world's airports are now full of staggeringly expensive "security" hardware that doesn't bloody work at all, so a country with a GDP per capita a sixth that of Australia, and with the usual ex-Soviet wall-to-wall government corruption, could be worse. But the tours are a regular event now, so even the defective imaginary-terrorist-obsessed Western world's governments would probably have noticed people coming back with shoes that glow in the dark.
Plus, I'm sure plenty of people have taken their own Geiger counters with them on these tours, and yet the most newsworthy result of a trip to Chernobyl remains that chick who pretended to have taken a solo motorcycle tour.
On the subject of Geiger counters, I think it's important to mention that if you decide to get yourself your very own ionising-radiation meter, be aware that there are two basic kinds on the consumer market. Both may be sold as "geiger counters", but only one of them is.
A geiger counter can measure low levels of radiation. You can, for instance, use a geiger counter capable of detecting alpha particles (which many can't) to verify that a lump of unremarkable granite measures above (but probably nowhere near dangerously above) the background level of radiation. (Unless your house is built on granite!)
The other kind of radiation meter is the "ion-chamber survey meter", which is much less sensitive. If the needle on a survey meter ever budges, you should get the hell out of there. Survey meters are only meant to be used in places with high radiation levels, like serious nuclear accidents or after an actual nuclear war.
A lot of cheap eBay radiation meters are the distinctive yellow US Civil Defense versions, which come in geiger and ion-chamber versions. If it's pleasingly cheap, it's probably a useless ion-chamber meter.
(Note also that if Australians buy a geiger counter from overseas, it may not make it through Australian Customs, especially if it comes with a mildly radioactive calibration object.)
It is unlikely that any Chernobyl/Pripyat tours go anywhere remotely hot enough to get a reading from an ion-chamber meter, though you may be able to see places that'd be hot enough, like the secured, deserted scrapyards where they parked the emergency vehicles used during the disaster, or particularly choice parts of the Red Forest.
And yes, dirt or otherwise broken ground around Chernobyl is in general more radioactive than hard surfaces, because rain washes particulates off roads and footpaths and buildings onto soil, where they accumulate. Chernobyl is a particularly delightful test case for this phenomenon, because the combination of the reactor's design and the astonishing fuck-ups that led to the disaster meant that the Chernobyl accident caused a roaring fire in its graphite moderator, spewing a vast plume of radioactive smoke into the sky and raining particulate fallout over a huge area.
(The far less disastrous Windscale fire happened in a graphite-moderated reactor too, but it was the fuel burning that time, not the moderator.)
The recent TEPCO disaster in Japan has released an amount of radioactive material comparable with Chernobyl. The Fukushima Daiichi reactors don't have much burnable stuff in them, though, so most of the escaped isotopes are just sitting around in the neighbourhood of the reactors, or washed away into the ocean where tedious scientists say they're diluted out of significance but we all know they'll really wake up Gojira.
I am, of course, kind of winging it on this answer, because I am indeed not what you'd call an expert on the particular perils of tramping around in the Zone of Exclusion. (I'd probably walk straight into an anomaly and die.) I invite readers to tell me what I've overlooked, and thereby scare the tripes out of Roscoe.
22 August 2011 at 12:04 am
You overlooked the fact that the graphite moderator at Chernobyl didn't actually burn (nuclear graphite it pretty damn hard to actually ignite).
22 August 2011 at 1:28 am
I'm deeply interested in anything involving Chernobyl and other nuclear disasters, for reasons I don't quite understand myself, so I read this post with extreme interest.
Anon: pretty sure the graphite did burn - temperatures in the blown reactor were so obscenely high that the graphite got beyond the several thousand °C ignition point, and did.
Other than that, one more thing that certainly didn't help matters was the Mi-8 helicopter that hit a crane and dropped like a stone in the burning reactor...
Also, one slightly funny fact: I know of several people who have stopped eating sushi after the Fukushima disaster because they're afraid it's made from contaminated fish. When someone told me that the first time I was too busy laughing to facepalm, but nowadays I just sigh and try to pretend I'm not hearing their words.
22 August 2011 at 4:34 am
I would agree with Dan that if the items in question have been washed, they're probably safe. I'm no expert either, but I do have a pretty snazzy Ludlum model 14c geiger counter which I've spent a lot of time playing with.
Last year I used it to find a guy selling radium clock hands at a convention. They're really intensely radioactive by household standards even after something like 80 years. I bought them figuring they would be safer with me. Now they reside in a thick metal box behind some CRT monitors in my workshop.
I just pulled the hands out and measured the empty box. Even after a year with those very radioactive hands inside, the box reads about as radioactive as my tritium keychain, and only slightly more than a banana. I've got clay bowls which read just as high. Now I'll admit that radium isn't really the same as the contents of a nuclear power plant, and that different materials will absorb different amounts, but still, a years exposure only left the box very slightly radioactive once the source was removed. Surely some shoes that were exposed to high background radiation for an afternoon and then washed should be okay.
After the Fukushima disaster, I considered renting myself and my geiger counter out on Craigslist to paranoid people. After all, how many people have said "stupidity should cost money"? Seems to me I could make it happen.
22 August 2011 at 6:59 am
The danger with radium clock hands is the radium getting loose. (Or, in one of those retrospectively horrifying events, the women painting radium onto them in WWII factories licking their brushes.) If the radium is embedded in paint, you're probably fine until the paint starts flaking off. On the other hand if the radioactive material is in the form of a fine dust, well, that's more of a problem - for tritium as much as for radium, not to mention the gunk that came out of the Chernobyl reactors. Even more so if the material is water-soluble and somehow gets into something you're drinking. (Though the lungs are more of a concern than the digestive tract, because the body just isn't that good at getting radioactive particles out of the lungs.)
Incidentally, if granite really does produce only alphas in significant quantity, I wouldn't worry too much about a house built on granite - the aplhas will be stopped by the basement floor. Granite dust is another story, again, but there you're probably saved by the fact that it would take a very great deal of dust - probably enough to do you harm directly - to get any substantial amount of radioactive material into your body.
22 August 2011 at 9:24 am
The problem with houses built on granite isn't the alphas but the radon that's part of the decay chain. Such houses tend to need forced ventilation to keep levels down.
22 August 2011 at 1:21 pm
Fallingwater: For the graphite to burn you'd pretty have to sublimate it first or chemically react it with something else (water for example, but then it won't actually be burning graphite but burning hydrogen and carbon monoxide).
Anne: The problem of radium girls licking their brushes got solved once some of them decided to sue over it and with the proper precautions (which they should have used much earlier than they did) can be done safely, of course now that nuclear reactors can make safer isotopes for us we've basically stopped using radium (which is chemically similar to Calcium so if you get it in you it ends up in your bones).
Tritium is relatively benign by the standards of radioactive substances (it doesn't hang around and is of rather low energy).
23 August 2011 at 9:05 pm
"the most newsworthy result of a trip to Chernobyl"
Oh, no, I reckon it's that reporter who set the alarm on their digital radiation meter to trigger at some small fraction of a milliSievert per hour, and proceeded to film a story about how dangerous the radiation was even 25 years later, because their radiation alarm kept going off... can't remember who it was, it was some American network, I think. Have seen the same sort of stunt pulled around Fukushima Daiichi, too.
Meaningful? Informative? Not misleading?
Hell no.
But "news-worthy", in terms of selling ad space? Hell yeah!
23 August 2011 at 11:55 pm
Heh. I had an Australian relative who happened to like a spot of geology driving around with a fairly large chunk of uranium ore in the boot of her car along with various other odds and ends she collected around the country for many years.
Only became an issue when she emigrated to NZ and tried to bring the car over with her. Australian Customs gets rather excited when their radiation meters go off, and point blank refused to let her keep the rock.
Wasn't particularly dangerous, just a nice natural source of things that go ping...
She still complains about it whenever she teaches a class on radioactivity and a demonstration would be useful.
10 January 2012 at 10:02 pm
There is a certain amount of irony (newfangled irony, not the traditional kind) in Australian customs being picky about letting radioactive items *into* Australia...
Considering that Australia is one of the worlds leading nuclear reactor fuel exporters...
(or are they worried that Oz is too full of radioactive things & one more might make the whole place go critical?)
Cheers
11 January 2012 at 1:07 am
Of course the exported U eventually (after enrichment, fuel fabrication, etc) goes to places (mainly nuclear power plants) which have radiation safety specialists on staff at all times.
Besides, I'm sure ANSTO could get almost anything radioactive through customs.