It's a problem for fabrication of plutonium fuel for reactors because oxide fuel is made by sintering pellets and then carefully handling them and stuffing them into a tube with gloves. The only way known to make high quality mixed-oxide fuel (Pu fissile and U fertile) is to alloy the oxides with a high energy ball mill -- the ball mill can turn silica into dangerous nanoparticles, but with Pu it's much worse.
At the factory Karen Silkwood worked at they couldn't ever keep dust down to levels that would be considered safe by US regulator so they had to wear respirators all the time which is considered a "normalization of deviance". I think they closed down a planned MOX plant at the Savannah River
over these issues. The French think it is OK, the epidemiology was controversial for a long time because of the "healthy worker" effect (people who work are almost always healthier than the population as a whole unless the place is a real deathtrap like the mine at Libby, Montana) but the American point of view has gained in recent research
Yeah, when you're working with it the dust can be an issue--most inorganic dusts are very much not good things to be inhaling. But that's an issue for the workers, not an issue for the people at large.
sillywalk 2 days ago [-]
Interesting read. I'd add chlorine trifluoride to the running for most dangerous substance. From the book Ignition!, as quoted in [0].
”It is, of course, extremely toxic, but that's the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water-with which it reacts explosively. It can be kept in some of the ordinary structural metals-steel, copper, aluminium, etc.-because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on aluminium keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes.”
I'd much prefer to deal with Pu than ClF3. Reasonable care will keep you safe around the Pu, any little flaw that you have no idea exists can unleash the ClF3 demon.
But why stop at ClF3? FOOF seems an awful lot more dangerous, you can at least cage the ClF3 demon, nobody's crazy enough to even try with FOOF. FOOF will detonate if it gets too warm (and that's at cryogenic temperature.) It will detonate if it's disturbed. It will detonate if you look at it (photosensitive, not the actual looking.) It might detonate for no reason at all.
LorenPechtel 2 days ago [-]
I have a big gripe with this article, there's an apples-to-oranges that is completely invalid. Harry Daghlian, died from an acute exposure to 5.9Sv. Albert Stevens received a slow dose of 64Sv and doesn't seem to have died from it. (To those who object to it being different forms of radiation: the Sievert is already scaled to human response.)
The problem is there are two separate threats. An acute exposure has an LD50 of 4Sv. By the LNT theory the chronic exposure LD50 is 100Sv. Entirely separate mechanisms, just because both are due to radiation doesn't mean they should be compared. (Simple test: what's your chance of surviving an hour in 1000F? None, of course. Should we conclude that you have no chance of surviving 100F for 10 hours??)
(I do have a gripe with the LNT theory, though--a straight line is the simplest curve to fit but the data is very sparse and has no data points anywhere near the zero. A parabola is at least as good a fit and probably a better fit if you include the no-data cases--studies of populations that were exposed but no excess mortality is seen.)
2 days ago [-]
Rendered at 12:46:59 GMT+0000 (Coordinated Universal Time) with Vercel.
At the factory Karen Silkwood worked at they couldn't ever keep dust down to levels that would be considered safe by US regulator so they had to wear respirators all the time which is considered a "normalization of deviance". I think they closed down a planned MOX plant at the Savannah River
https://www.armscontrol.org/act/2018-11/news-briefs/doe-term...
over these issues. The French think it is OK, the epidemiology was controversial for a long time because of the "healthy worker" effect (people who work are almost always healthier than the population as a whole unless the place is a real deathtrap like the mine at Libby, Montana) but the American point of view has gained in recent research
https://pubmed.ncbi.nlm.nih.gov/28520643/
”It is, of course, extremely toxic, but that's the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water-with which it reacts explosively. It can be kept in some of the ordinary structural metals-steel, copper, aluminium, etc.-because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on aluminium keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes.”
[0] https://www.science.org/content/blog-post/sand-won-t-save-yo...
But why stop at ClF3? FOOF seems an awful lot more dangerous, you can at least cage the ClF3 demon, nobody's crazy enough to even try with FOOF. FOOF will detonate if it gets too warm (and that's at cryogenic temperature.) It will detonate if it's disturbed. It will detonate if you look at it (photosensitive, not the actual looking.) It might detonate for no reason at all.
The problem is there are two separate threats. An acute exposure has an LD50 of 4Sv. By the LNT theory the chronic exposure LD50 is 100Sv. Entirely separate mechanisms, just because both are due to radiation doesn't mean they should be compared. (Simple test: what's your chance of surviving an hour in 1000F? None, of course. Should we conclude that you have no chance of surviving 100F for 10 hours??)
(I do have a gripe with the LNT theory, though--a straight line is the simplest curve to fit but the data is very sparse and has no data points anywhere near the zero. A parabola is at least as good a fit and probably a better fit if you include the no-data cases--studies of populations that were exposed but no excess mortality is seen.)