There’s just been a james Bond movie on TV here - in which nuclear warheads were dismantled and cantaloupe-sized hemispheres of ‘weapons grade plutonium’ were removed and handled by various people (bare hands) with complete impunity (in fact, they kept saying “it’s not dangerous to handle”).
Am I right in assuming this is complete tosh? (BTW, I’m not under the false impression that the actors were indeed handling plutonium; I’m asking whether, in reality, chunks of plutonium from a real-world nuclear weapon could ever be passed around at the coffee table casually as in the movie)
Solid plutonium in large chunks (provided they are well below critical mass) is pretty safe. You don’t want to inhale it or ingest it or get it into your body like through a cut.
I recall reading some physicist associated with the early bomb programs recalling handling ne of the sub-critical masses. It was warm, not cold as you’d expect, because of the reactivity.
I wouldn’t want to go handling it for a long period of time – the alpha and beta radiation from the plutonium is stopped by skin, but any inhaled dust can wreak havoc. the gamma levels are not lethal, but I’d still worry about them (whether with cause or not). the metal is pyrophoric, and even though it’s all in a big chunk I’d tend to worry. If it were me, I’d put a hand on it to feel it (and to say I did so), then get it safely under wraps pretty fast.
I don’t think there is much to worry about when handling solid chunks of plutonium or highly-enriched uranium, besides an accidental criticality. That’s assuming that it’s properly protected against corrosion by plating. Plutonium reacts badly to direct exposure to oxygen and moisture. Some movies portray nuclear weapons as death in a bottle, where any damage to the integrity of the weapon’s casing results in severe radiation exposure to anyone nearby. I think that’s just ignorance on the part of the writer.
I write safety basis documents for a facility that processes weapons grade plutonium. The previous four posters have it pretty much covered. During process hazard analysis, prevention of criticality is addressed very seriously. Several processes are done in the aqueous state, so geometry of containers (including overflow containment) is always taken into consideration. Processes are done in gloveboxes that are purged of oxygen and moisture, due to metal plutonium’s extreme pyrophoric nature. If the metal oxidizes, uptake becomes the biggest concern.
I’m not sure how warm Pu239 (weapons grade) is, but Pu238 (heat source) glows orange. I wouldn’t want to pick that up with my bare hands, because I wouldn’t want to burn myself. As the previous posters have stated, though, alpha and beta particles are mostly blocked by already dead skin cells, so gamma rays would be the biggest concern. Handling it for short amounts of time, however, won’t pose much of a threat. Pilots and flight attendants get between 10 and 100 times the radiation as the workers in our facility are allowed to receive.
I wouldn’t go so far as to say it’s not dangerous to handle, because the outer layer will be oxidized, and your hands will rub it off. PuO2 is the dominating substance evaluated when determining accident severity. This severity is usually determined by estimating the uptake of the maximally exposed off site individual. However, I would say that it’s not unrealistic to expect the handling of weapons grade to not have any immediate adverse consequences.
I’ve just kind of skimmed over the basics, and expanded what others have said, but if you have any questions, I’ll see if I can field them.
A couple of years ago Joan Lunden did a series called Behind Closed Doors. It was a documentry on things not usually seen by the public. I remember in one of the episodes she handled a cantaloupe sized sphere of something, with nothing but a pair of white gloves. Now if I could only figure out what it was. Anyone else remember that?
You’re no doubt thinking of Feynman’s account in Surely You’re Joking … of accompanying Henry DeWolf Smyth round Los Alamos and showing him a warm, touchable sphere of plutonium.
I used to work at a DOE facility in Miamisburg, OH. I worked in a lab that designed and developed calorimeters. (This paper contains some pics of the calorimeters we built.) We used two kinds of heaters to calibrate the calorimeters: electric heaters and plutonium. Plutonium was the best, since no wires were required.
We had about 100 plutonium heat standards. The standards produced power in the form of heat. They ranged anywhere from around 1 μW to 60 W. The 60 W standards were about the size and shape of a beer can. You had to be careful with the 60 W standards. If you place one on a piece of wood for more than a minute, it will leave a burn mark in the wood. (I, um, learned this first hand.)
Now you’re probably wondering… how did you handle those standards? Weren’t you afraid of getting contaminated? And if they’re glowing bright red, were they blinding?
Here’s the deal… each plutonium specimen was triple-encapsulated in (I believe) stainless steel. In other words, the plutonium was put inside a steel container and welded shut, then this was put inside a slightly larger container and welded shut, then this was put inside a slightly larger container and welded shut. This means the following:
It was virtually impossible to come into direct contact with the plutonium.
Since you can’t see through stainless steel, you can’t see the visible radiation emitted by the plutonium sources.
While there was virtually no chance of becoming contaminated with plutonium, the sources did produce some radiation at very short wavelengths (mainly gamma, I think). Even though we wore dosimeter badges, I didn’t want to be near them too much.
We stored the sources in “sand boxes.” These were boxes full of fine metal shavings. They helped to dissipate the heat over a large surface area so they wouldn’t burn anything.
I read an article on the possibility of a terrorist bomb (they need to lay their hands on 150lbs of U235 and build a gun-type weapon) and they noted that handling plutonium would be tricky due to heat, etc., but note that in the Bond film, they were handling a pit.
BTW, if someone were to take a bunch of pits an throw them into a pile, would you get an explosion or just a big blue glow or what?
I seem to recall that the Israeli spy (Mordecai Vanunu), while working in a top secret Israel nuclear bomb factory, photographed plutonium spheres. Apparently security was rather lax-Vanunu took pictures and sold them to a newspaper. I would not want to handle plutonium-if it gets into your body, you are in for some trouble.
This is making me think about a piece of fiction I read in *The New Yorker *in which a desperate Russian (or maybe Soviet?) nuclear plant worker decides to steal some plutonium, with the intent of selling it to some nuke-aspiring rogue nation. He’s doing it to secure his family’s future.
He steals granular plutonium and, through a series of mishaps, does not make his connection. He ends up being attacked by some thugs. The end of the story is that the thugs assume this granular stuff they’ve stolen is a drug, and they snort it. :eek:
Good question. You’d get some kind of a fizzle, but exactly what it’d look like is difficult to say.
Say you toss your fourth pit or so into a bucket. At some point in its trajectory, enough of the stray neutrons that all the pits are emitting will hit the other pits, so fission neutrons will be generated faster than they’re escaping. You’ve just crossed into marginally supercritical territory. Cut to extreme slo-mo.
As that pit carries on towards the bucket, the neutron population in the pits grows exponentially. People nearby receive lethal doses of neutron and gamma. They may see a blue flash from the Cerenkov radiation of neutrons passing through their eyeballs.
A whole lot of energy is being released. As the pit continues towards the bucket, the degree of supercriticality increases and the rate of fission and energy release increases. At some point, the energy release is going to blow the arrangement apart and remove the supercriticality. The question is, how much energy is released before that happens?
Maybe the intense gamma ionises and superheats the surrounding air and scatter the pits with a firecracker-strength explosion. Maybe the pits burst apart into exciting white-hot chunks and droplets of liquid metal. Plutonium apparently gives an unsatisfactory explosion even if put together with a gun-type assembly, so I’d expect plutonium pits to do little more than make a little bang, zap everyone nearby, and create a nasty contamination problem.
Uranium pits OTOH might yield a bit more, because a greater degree of supercriticality can be achieved before the chain reaction really gets going.
You will get the effects Matt mentioned at the addition of the second pit. Plutonium is very “aware” of other masses. Pits are very close to critical, and with no shielding, two pits will cause a fizzle, fires, radiation release, fragmentation, substantial pollution of the local environment.
Outside my weapons area really. Pure Pu-239 in any sort of non-engineered mass (lump) would spontaneously try to break up. The non-critical pits inside the warheads and inside the substantial metal shipping/storage containers were still hot in so far as readings went. The radiation geeks would have the detectors set to audible and the racket would substantially increase just moving one warhead by another in storage several feet away.
