Posted on 07/21/2005 11:25:01 AM PDT by Ditto
Pretty cool stuff, I'd heard it was warm to the touch.
fascinating
The description of the metal phases and their characteristics sounds like it is straight out of science fiction.
Plutonium of 200 grams or more can be used to build a bomb. It's twice the density of lead so the volume would be half the size. a very small package indeed. Thr Trinity explosion device was carried on his lap. An equally powerful explosion could be carried in a backpack onto a subway.......
Makes discovering all this by the WWII physicists all the more amazing. Hard to believe that much brain power could ever be assembled again.
On his... lap? What his kids look like???
Held my attention the whole way. Until now all I'd ever read on plutonium were the scare stories.
Criticality does not produce a nuclear bomb. It produces a nuclear "flash," which can be fatal to someone nearby, but it is not a bomb. Depending on the amount of fissile material present, a supercritical mass heats up slowly (or maybe quickly). If the amount of energy released is large enough, it melts, and, by melting, will put itself in a non-critical state (by spreading out into a pool). If the amount of energy released is very large, it vaporizes, again putting itself into a non-critical configuration. Although anyone with an unobstructed view of such an event would collect a lethal dose of radiation, this would not be an atomic bomb. It would be a very expensive dirty bomb.
An early fatality due to this effect was that of a physicist named Louis Slotin, who was demonstrating his technique for "tickling the dragon's tail," i.e. assembling a just-barely critical mass of plutonium by holding two Pu-239 hemispheres apart with the blade of a screwdriver and slowly allowing them to approach one another by twisting the handle of the screwdriver. During the demonstration, he allowed the screwdriver blade to slip out from between the hemispheres. In the resulting criticality "flash," Dr. Slotin accumulated a radiation dose estimated at 1100 rads in half a second. He died nine days after the incident, which occured May 21, 1946. Two of the observers present for the demonstration died within a few years, apparantly suffering symptoms of radiation poisoning.
(steely)
Not quite. The article says that Morrison carried the plutonium core on his lap. The entire device was much larger.
I doubt we are going to see terrorists using a nuclear explosive that can be carried in a backpack. However, a plutonium device would fit in a truck.
The first Darwin Award?.......
A bomb could conceiveably be made by surrounding the separated masses with a conventional explosive. Using them for an atomic explosion rather than a thermonuclear one. no?....
In Slotin's mishap, did it melt into a pool on his lab table?
No, it wasn't even the first time this had happened. An earlier fatality was that of Dr. Harry K. Daglian, who accidentally created a supercritical mass by dropping a tungsten carbide brick onto a spherical piece of plutonium. The WC brick reflected enough neutrons to make the configuration supercritical, and Dr. Daglian absorbed about 500 rads, which caused his death 24 days later. By the way, Dr. Daglian removed the WC brick as fast as he could, but not fast enough.
(steely)
oh yeah, and the original "hold my beer and watch this"
Not even close.
(steely)
hmmm... why didn't it roll off? I drop a brick on a ball, it just sits there on top?
Yeah, but did Pluto ever get any royalties for the use of his name?
Poor Pluto, all he ever got was a pat on the head and some dog food from Mickey, and his name gets ripped off for one of the critical ingredients in nuclear weapons.
Life isn't fair.
"I doubt we are going to see terrorists using a nuclear explosive that can be carried in a backpack. However, a plutonium device would fit in a truck."
The question is, with weapons grade plutonium being so unstable, and deterorating over time because of contamination by other elements, does that automatically mean that a weapon will significantly degrade over time, and will that degradation affect the yield??
We constantly hear of weapons being smuggled out of the former USSR, but if the weapons are twenty years old or more, will they be able to achieve fission after a given length of time?
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