Is nuclear fusion radioactive?

  • #1
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Main Question or Discussion Point

I was just wondering if nuclear fusion is considered a radioactive process?
 
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Answers and Replies

  • #2
Danger
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It is in a weapon, because a fission trigger is used. Pure fusion, such as in a reactor, is not. Fusion by-products stop at the stage of becoming iron, which isn't heavy enough to be fissile.
 
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  • #3
pam
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Fusion does produce neutrons which can be harmful.
One argument against "cold fusion" is that neutrons aren't seen in the experiments.
 
  • #4
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Hmm. A friend is telling me that "The fusion in the sun produces radiation of several types, including beta positive and gamma in huge quantities" Is this just radioactive waste?
 
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  • #5
Danger
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This might be just a matter of terminology. To me, the term 'radioactive' indicates a decay process. That might not be a proper definition. Of course, fusion releases EM radiation. So do light bulbs and radio stations, but I don't consider them radioactive. I was aware of fusion releasing protons, but not neutrons. Beta decay is just the release of electrons, which again is not something that I think of as being hazardous radiation. After all, that's what makes a TV work. Keep in mind that I'm not a scientist. My apologies if I misled you.
 
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  • #6
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No worries! Please don't apologize, I was just curious.
 
  • #7
Danger
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People come to PF expecting accuracy. If I offered false information, then I do indeed owe you and everyone else who reads this thread an apology.
Let's just hang around and wait for some experts to show up. That way, we can both learn from it. :smile:
 
  • #8
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To me, the term 'radioactive' indicates a decay process. That might not be a proper definition. Of course, fusion releases EM radiation. So do light bulbs and radio stations, but I don't consider them radioactive. I was aware of fusion releasing protons, but not neutrons. Beta decay is just the release of electrons, which again is not something that I think of as being hazardous radiation. After all, that's what makes a TV work.
To most people 'radioactive' means 'invisibly lethal', which isn't a good starting place (in actual fact everything and everyone is radioactive, to varying extents). This means the OP asked the wrong question (and should instead be asking "Is using fusion power safer than not using fusion power?". And it so happens that the answer is "probably" since the realistic alternatives have been shown more dangerous for complicatedly practical reasons).

Usually three specific types of emanation are recognised (being both potentially dangerous and common from the natural nuclear decay of many materials): (a) helium ions, (b) fast electrons, and (c) high frequency light. So, it is a danger (sorry) to categorically dismiss any of these. As for the question of whether fusion of light elements will produce any soon-decaying isotopes, sure: you'll sometimes produce unstable isotopes of light elements or transmute parts of the reactor casing.
 
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  • #9
Danger
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Take my name in vain, huh, you bastard? :tongue:

That was a nice response, Froggie. Very informative. That part about transmutation of the reactor casing never occurred to me.
 
  • #10
Astronuc
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The D + T reaction produces 14.1 MeV neutrons and 3.5 MeV alphas, and in that sense it's radioactive. The neutrons will slow activate the structure enclosing the plasma chamber, so some of the structure overtime will become radioactive.

The D + D reaction produce p + T or n + He3, with about a 50/50 split in probability. T is a low energy beta emitter. In the plasma, T will react with D, n's will leave the plasma, and He3 may react with D in an aneutronic reaction, (D + He3 -> p + He4).

There are other radiative processes in plasma that produce radiation, namely recombination (ions recombining with electrons - think Lyman, Balmer, . . . spectra) and bremsstrahlung radiation. With plasmas at keV energies, there is a fair amount of low energy gamma, X-ray and UV.
 

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