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Author Topic: Do hydrogen bombs cause radioactive fallout?  (Read 12768 times)

John Reid

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Do hydrogen bombs cause radioactive fallout?
« on: 17/08/2009 10:30:02 »
John Reid  asked the Naked Scientists:
   
Dear Chris,

I have been unable to get through to you during your weekly talk with Redi so I hope this does get through to you.
  
I have in recent years I have become totally absorbed with many issues relating to Einstein's theory and having read much including Stephen Hawkins A brief history of time and of course David Bodanis E=mc^2
  
  
NOW can you tell me and possibly many of your listeners:

The conventional nuclear bombs as fell on Japan were Plutonium fuelled and caused serious radioactive fall out. I presume this is because of the Uranium/Plutonium component. What would the radioactive fallout from a hydrogen bomb be considering that hydrogen is not radioactive to start with.
  
John D.M. Reid

What do you think?

syhprum

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Do hydrogen bombs cause radioactive fallout?
« Reply #1 on: 17/08/2009 12:28:52 »
www.progressive.org/images/pdf/1179.pdf

The above URL tells you how to build your own H-Bomb but it might not be wise to leave it on your computer too long.
Hydrogen bombs are triggered by fission bombs of at least the size of those that were used by the Americans against Japan hence the radioactive fallout from unconsumed Plutonium will be just as great.
The proportion of casualties caused by radioactivity is quite low most people are either blown to pieces or burnt to death!

syhprum

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Do hydrogen bombs cause radioactive fallout?
« Reply #2 on: 25/08/2009 07:20:50 »
Why no further replies, too sensitive a subject ?

Nizzle

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Do hydrogen bombs cause radioactive fallout?
« Reply #3 on: 25/08/2009 07:33:28 »
Oh, I was under the impression the question was answered..

Batroost

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Do hydrogen bombs cause radioactive fallout?
« Reply #4 on: 25/08/2009 19:07:15 »
As you say, most natural hydrogen is not radioactive (i.e. excluding a small natural tritium content. But, during a fusion reaction both ionising and non-ionising radiation (e.g. neutrons, gamma rays, x-rays and alpha and beta particles) will be produced. Some radioactive isotopes (e.g. tritium) will also result from the reaction.

More signifcantly, if a fusion bomb is exploded close enough to ground level a significant quantity of surface soil, water, plants etc.. will be lifted and activated by the intense radiation. This can give a very wide variety of radioactive isotopes which will be manifest as 'fallout'.

Tests have shown that a fusion bomb exploded high enough produces less fallout, but syphrum says, the fission trigger can be significant on its own.

LeeE

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Do hydrogen bombs cause radioactive fallout?
« Reply #5 on: 26/08/2009 17:02:39 »
Weellll... it's not just the fission trigger that's the problem but the fission secondary that's used in most 'hydrogen' bombs.  What we think of as 'hydrogen' bombs are mostly two stage fission-fusion-fission devices where the great majority of energy is released by fission of the secondary.  The primary fission trigger supplies the energy to induce fusion in the fusion fuel but the fusion energy is then used to initiate fission in a much larger amount of additional U235/238.  What is thought of as 'clean' hydrogen bombs are really just ordinary fission-fusion-fission bombs where the uranium secondary tamper is replaced with one of lead, so you get no secondary fission.  These 'clean' versions are naturally much weaker than the 'dirty' versions.

As batroost says though, detonating a 'clean' fission-fusion bomb close to the ground will still produce a lot of fallout.
« Last Edit: 26/08/2009 17:04:16 by LeeE »

Bored chemist

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Do hydrogen bombs cause radioactive fallout?
« Reply #6 on: 26/08/2009 17:53:26 »
I'm fairly sure that at least some of the "hydrogen" in an H bomb is tritium anyway so it is radioactive. Also, I think that one aspect of the bomb's design is a thick layer of depleted uranium acting as deadweight to contain the initial explosion in order to improve transfer of energy to the fusion fuel.
That tamper becoes intensely radioactive fallout too.

 

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