Touching weps grade uranium/plutonium

[Paulanddiw]

It takes quite a bit of effort to get a mushroom-type explosion. You have to hold the fissile bodies near each other for an period of time for the neuton flux to build up. If you don't, the bodies will just get hot and melt. Pu and/or U melt at red heat, so it'd probably burn up you bench that you'd be experimenting on. Of course, there will be an enormous gamma radiation emission during all of this. Easily kill a person.

 

[sean_omahoney]

@Moribus

What would happen if you were to touch nuclear waste out of a plant?


(It's my homework assignment.)

 

[QuantumPion]

Morbius, I was under the impression that Pu is one of the most radiologically toxic substances on earth.

No on both sides. There are non-radioactive molecules which are fatal in far more miniscule amounts, such as Dimethylmercury. And on the radioactivity side, plutonium is not very dangerous compared to, say Cobalt-60 (strong gamma emitter) or Iodine-131 (short half life, concentrates in body).

 

[QuantumPion]

@Moribus

What would happen if you were to touch nuclear waste out of a plant?


(It's my homework assignment.)

You wouldn't be able to. A rad engineering co-worker of mine once did a calculation: if you placed an unshielded spent fuel assembly at one end of a football field, and starting from the other end, ran right towards it, you would drop dead of radiation poisoning at about the 15 yard line.

 

[nikkkom]

You wouldn't be able to. A rad engineering co-worker of mine once did a calculation: if you placed an unshielded spent fuel assembly at one end of a football field, and starting from the other end, ran right towards it, you would drop dead of radiation poisoning at about the 15 yard line.

I wanted to point something similar about how deadly spent fuel is, but then I realized that question has too many unknowns to make sense.

How big the chunk of waste I'm trying to touch - kg? gram? nanogram? How old the waste is - 1 day since reactor was scrammed? 10 years? 10000 years?
"Nuclear waste out of a plant" is what exactly? Spent fuel? All non-fissile materials in spent fuel? (If yes, from which reactor exactly?) The output of La Hague? (If yes, (1) in what form - raffinate? Glass?... (2) from what day and batch of fuel?).
Etc. etc. etc.

Depending on these additional data, the answer ranges from "we touch this waste every day (when, for example, we inhale air with a few atoms of reactor-produced Kr-85 in it)" to "you would die".

 

[Rive]

You wouldn't be able to. A rad engineering co-worker of mine once did a calculation: if you placed an unshielded spent fuel assembly at one end of a football field, and starting from the other end, ran right towards it, you would drop dead of radiation poisoning at about the 15 yard line.

It would be interesting to see (and redo) that calculation, because it sounds really ridiculous.

Chernobyl had some (really fresh) spent fuel around during the cleanup, and part of it was cleaned up manually. With only a few direct fatalities - and none of those fatal radiation poisonings were the 'dropping dead' kind.

Ps.: by the previous conversations here in the forum I have the impression that 'average' spent fuel has a surface radiation of 100-1000 Sv/h. If so, then you can touch it. At least once...

 

[nikkkom]

It would be interesting to see (and redo) that calculation, because it sounds really ridiculous.

Chernobyl had some (really fresh) spent fuel around during the cleanup, and part of it was cleaned up manually. With only a few direct fatalities - and none of those fatal radiation poisonings were the 'dropping dead' kind.

Soviet authorities did not bother tracking the fates of the conscripts who performed that work. I have a reason to believe that the fatalities were much more numerous that "a few": these young boys were just discharged from the service and sent back home to "rest", where they soon died from "unrelated causes".

 

[nikkkom]

Ps.: by the previous conversations here in the forum I have the impression that 'average' spent fuel has a surface radiation of 100-1000 Sv/h. If so, then you can touch it. At least once...

He said "if you placed an unshielded spent fuel assembly...". Typical fuel *assembly* is several meters long and has more than 50 fuel rods. So, you need to multiply your levels by about 100...

 

[Rive]

Soviet authorities did not bother tracking the fates of the conscripts who performed that work. I have a reason to believe that the fatalities were much more numerous that "a few": these young boys were just discharged from the service and sent back home to "rest", where they soon died from "unrelated causes".

A tracking record exists. However... Even you are talking about young men who were sent home. The secondary meaning of this is that they left the site alive. So they did not 'dropped dead on the 15 yard line'...

He said "if you placed an unshielded spent fuel assembly...". Typical fuel *assembly* is several meters long and has more than 50 fuel rods. So, you need to multiply your levels by about 100...

For surface radiation? I don't think so. IMO a cylindrical source with different diameter, but with a similar surface radiation will do for a simplified calculation.

 

[Dmytry]

re: plutonium dust inhalation: alpha particle emitting strongly radioactive dust in lungs should not be expected to have identical biological effects to more uniform sources. Such dust particle would burn away the tissue around itself, leading to a tiny necrosis while the nearby cells would regenerate (divide).

The one rather interesting thing about nuclear power is that the nuclear power plant really does have rather staggeringly huge toxic repository (measured in LD50s) compared to a toxic chemical plant, even if you consider just the internal exposure to Cs-137 and/or I-131
I did comparison between Bhopal and Chernobyl release based on WHO figures for internal exposure from consumed caesium and iodine.
http://dmytry.com/blog/?p=15

That shouldn't be very surprising though; for the amount of deposited energy, the radiation is very lethal; the energy that heats you uniformly by 0.001 K would kill you if delivered in form of ionizing radiation, but not in form of almost anything else (unless concentrated on vital organs, e.g. stabbing or gunshot).