Radioactive Decay

Alzarakh

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Science people needed.

As far as I understand Uranium eventually decays into Lead. Would that lead still be considered radioactive and dangerous afterwards?

Example: There's a lump of uranium and a Character picks it up to absorb the energy. (This is fantasy based but I want it to at least somewhat follow science) This absorption turns it into lead (decays it super fast). Could the character then pass it to his friend with no ill effects?

The main idea I'm going for is to have this character be able to clean up nuclear waste by absorbing the radiation. Is it plausible that in doing so they would just leave a fine dusting of lead everywhere if a bomb had been exploded? I know air doesn't transmit the alpha particles well and neither does water but for fantasy sake they would just stand in the crater and suck it all up kind of like a vacuum; turning the radioactive particles into their decayed states and making it habitable again.
 

cornflake

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There are geologists and stuff who will be waaay better at answering this but that doesn't make sense to me.

I don't think 'absorbing the energy' speeds up radioactive decay? I think you need a nuclear reaction of some kind or a massive, specific magnet, to move electrons, no? There are different types of decay too, iirc.

Also, the half life of uranium is bananas, isn't it? Ecological kind of timelines.
 

Alzarakh

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That's the fantasy element. The decay would be a few seconds instead of millenia.
 

morngnstar

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Not exactly right. Uranium if left alone will eventually decay into lead. And you're right, the lead is safe and 100% non-radioactive. However, when it undergoes fission in a reactor or bomb, uranium produces different products, e.g. strontium. Those are what are termed as "nuclear waste". Those products also decay, and eventually will lead to non-radioactive elements, but different ones than lead. Your general principle makes sense (except that there is no known physical means to speed up or slow down decay, but you're allowed that as your One Big Lie), but the actual products would be a variety of elements, not lead.
 
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blacbird

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As far as I understand Uranium eventually decays into Lead. Would that lead still be considered radioactive and dangerous afterwards?

Uranium-238, the most common isotope of uranium, decays through about 14 intermediate steps into Lead-206, which is radiometrically stable (non-radioactive). U-235, the fissionable isotope, also decays eventually into Pb-206. The half-life decay of both these isotopes is very long, ~4.5 billion years in the case of U-238. Half-life is the amount of time it takes for half of a radioactive isotope to decay into a stable "daughter" isotope. The length of a radioactive half-life is specific to each individual unstable isotopes, and can range from microseconds to many billions of years. And they are stochastic physical constants, not subject to alteration via artificial means.



Example: There's a lump of uranium and a Character picks it up to absorb the energy. (This is fantasy based but I want it to at least somewhat follow science) This absorption turns it into lead (decays it super fast). Could the character then pass it to his friend with no ill effects?

The main idea I'm going for is to have this character be able to clean up nuclear waste by absorbing the radiation. Is it plausible that in doing so they would just leave a fine dusting of lead everywhere if a bomb had been exploded? I know air doesn't transmit the alpha particles well and neither does water but for fantasy sake they would just stand in the crater and suck it all up kind of like a vacuum; turning the radioactive particles into their decayed states and making it habitable again.


Scientifically, this is utter nonsense.

caw

blackbird, Ph.D., Geology, University of Iowa, 1981
 

GeorgeK

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It's no worse than any other super hero story like radioactive spiders. I think it could work especially well as a graphic novel concept. As morningstar said, in fantasy stories you get one big lie. If you want to assuage some irked people you can have some other character comment, "How does that work? Shouldn't it be some conglomerate of other elements besides lead?"

"Dude, I just do it. I don't know how it works."

Those people who are going to obsess about the physics involved aren't your target audience anyway.
 

King Neptune

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I've read sillier ideas. But the answer is that the lead that is a decay product of uranium is ordinary, non-radioactive lead. If you need a pseudo-scientific way to explain the fast decay, then say that that character's touch causes a nuclear fission with lead and something else being the results.
 

GeorgeK

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I've read sillier ideas..
Yes, this!
I think actually if you're going with the super hero concept, the anvil is ripe for the striking if your heroes can clean up nuclear waste dumps. It's a very green idea. Name him or her Verd...maybe Vern?
 

Twick

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Yes. Radioactive decay goes from unstable (radioactive) to stable (non-radioactive). So, if your character has "The Touch" to somehow accelerate radioactive decay, that should result in end product that's non-radioactive.

Of course, there should logically be a very quick and intense release of energy as all the atoms decay at once, but if you can technobabble accelerating decay you should be able to technobabble that problem as well.
 

GeorgeK

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Of course, there should logically be a very quick and intense release of energy as all the atoms decay at once, but if you can technobabble accelerating decay you should be able to technobabble that problem as well.
Yes and if I were writing this superhero I'd have him or her yell and glow and finally crumple to the ground upon which green things would start to slowly (well technically quickly if you can watch them grow) grow up in a rather uncontrolled fashion.
 

WeaselFire

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The main idea I'm going for is to have this character be able to clean up nuclear waste by absorbing the radiation.

There is no current scientific basis for this to happen, so you're basically on your own here. Current physics has no way to change a half life or decay period, and there is no known way to absorb radiation and leave only inert byproducts. If it were sci-fi, I'd say to rethink it. It's fantasy, so you'll have to develop your world to account for this, or at least the reader's suspension of disbelief.

Jeff
 

Alsikepike

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There'd be other radioactive elements produced from the decay to worry about, but it sounds plausible overall. Of course a, 'habitable' environment is kind of subjective considering that you'd still be dealing with a very toxic material that is now in a fine, powdered form that can be easily inhaled or absorbed through the skin. But exposure to lead will take a helluva lot longer to kill you than radiation poisoning, so it works well enough. I'd say go for it.
 

King Neptune

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Yes, if U238 fissioned so that most of it would end up as Lead 207, then the other fission product would be Phosphorus, which has an atomic weight of 31, and U235 would fission so that most of it would end up as Lead 207, and the other fission product would be Silicon, which has an atomic weight of 28. Both Silicon and Phosphorus are stable; although there are radioactive isotopes of both. Any missing mass would be converted to energy, and the hero would absorb that.
 

morngnstar

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There is some misunderstanding about the difference between fission and decay here. They are two different things.

Decay converts uranium to lead through several intermediate steps. This happens spontaneously at a slow rate, taking billions of years before most of the uranium is converted.

Fission splits a uranium atom into two smaller atoms, neither of which is lead. Both are about half the weight of uranium, although usually it's a little bit uneven. A very small amount of this happens spontaneously, but much more happens in a reactor or a bomb.
 

King Neptune

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There is some misunderstanding about the difference between fission and decay here. They are two different things.

Decay converts uranium to lead through several intermediate steps. This happens spontaneously at a slow rate, taking billions of years before most of the uranium is converted.

Fission splits a uranium atom into two smaller atoms, neither of which is lead. Both are about half the weight of uranium, although usually it's a little bit uneven. A very small amount of this happens spontaneously, but much more happens in a reactor or a bomb.

And what would the difference between instantaneous decay in which all of the emitted particle were kept together and nuclear fission. I brought up fission, because it better fits the beginning and end products that were desired.

By the way, there has been at least one example of a natural fission reactor, and this thing lasted for a long time.
https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor
 

morngnstar

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And what would the difference between instantaneous decay in which all of the emitted particle were kept together and nuclear fission.

Fission is by definition the breaking of a nucleus into at least two particles of similar mass. By contrast most decay emits a very light particle (a helium nucleus at the heaviest) and leaves most of the mass behind. Fission of uranium into lead and neon is possible, but would be extremely rare. Almost all uranium fission products are between 80 and 160 amu.

https://en.m.wikipedia.org/wiki/Fission_products_(by_element)

By the way, there has been at least one example of a natural fission reactor, and this thing lasted for a long time.
https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor

A natural reactor will work similarly to a man-made reactor and will not produce lead.

However, nuclear waste does contain a significant amount of the original uranium-238, which does not fission. That's not actually the dangerous part, but if you did accelerate its decay, it would produce lead, in addition to smaller quantities of other stable elements. So I think the premise works.
 

Mark HJ

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Are you going to jump straight from uranium to lead, or go through all the intermediates as well? I ask because U238 (the commonest isotope) has Radon as one of its intermediates, and Radon is a gas, so there would be a very loud pop as the gas leaves the area. Unless your character can somehow contain said gas, it's going to get away before you can head on downwards towards lead.

With a quick and dirty calculation, a cubic centimeter of uranium instantly converted to radon would give you about 1.8 litres of gas, so about an 1800 times expansion.

The radon is easily inhaled and very radioactive with a half-life of about four days... not a good thing to breathe in or have hanging around.
 

E. Steve

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Uranium-238, the most common isotope of uranium, decays through about 14 intermediate steps into Lead-206, which is radiometrically stable (non-radioactive). U-235, the fissionable isotope, also decays eventually into Pb-206. The half-life decay of both these isotopes is very long, ~4.5 billion years in the case of U-238. Half-life is the amount of time it takes for half of a radioactive isotope to decay into a stable "daughter" isotope. The length of a radioactive half-life is specific to each individual unstable isotopes, and can range from microseconds to many billions of years. And they are stochastic physical constants, not subject to alteration via artificial means.






Scientifically, this is utter nonsense.

caw

blackbird, Ph.D., Geology, University of Iowa, 1981

I read a book once where they carbon dated a rock. Nonsense abounds in fiction, and if as GeorgeK says and you "get one big lie", this is as good as any.