Deactivating radioactive waste

[SkepticLance]

Just encountered an interesting article that suggests a neutron bombardment method might, in a couple of decades, be able to speed the decay of radioactive waste in hundreds of years.

 

http://www.sciencedaily.com:80/releases/2008/09/080922100148.htm

 

If so, this would be a great development, and would enhance nuclear fission as an energy source. Anyone got any further information?

[npts2020]

I have been interested in the mechanism of radioactive elements' decaying for a long time now and have never seen a good explanation for the cause. My question about bombarding something like that with neutrons, is why are the neutrons in a reactor insufficient to do the same thing (most things coming out of any reactor are more radioactive not less)? Sounds like somebodies high-tech scam to get money from the gov to me.

[Mr Skeptic]

The trouble is where do you get the neutrons? Getting neutrons from fission generates more radioactive material. Getting neutrons from fusion is still impractical and I doubt anyone would want their big expensive fusion reactor stuffed full of radioactive waste.

[Gilded]

Well, fusors aren't too expensive or impractical as far as neutron sources go.

[John Cuthber]

The problem is that for some isotopes it would help to irradiate them and turn them into somethinmg else (with a shorter half life for example) for a lot of other isotopes irradiating it would turn it into something more hazardous.

The only way it would work would be if you could separate out each element in the waste, then separate the individual isotopes of each element, then treat those resulting isotopes which would "benefit" from treatment.

I don't see how it will ever be practical.

[SkepticLance]

As I understand it, the energy carried by the neutrons is critical. You have to extract and separate the most radioactive isotopes, and expose them to the correct number of neutrons at the correct energy levels. This does not happen inside the reactor.

[Physiman]

I do not understand one word u guys are saying.

But someday I will! ; )

[swansont]

Yeah, I saw this earlier. The article is remarkable short on useful information.

 

Typically these are alpha decayers, so by activating them you have them beta decay with a much shorter half-life, and that gets them into a different decay chain. Isotopes with a million-year (+) half-life are going to be low-level waste, because the specific activity is small, so this isn't a huge priority. Along the same lines, isotopes with really short half-lives decay quickly, so they aren't a problem either — the activity quickly drops to levels that aren't much of a problem. The real issue is the isotope with the 1,000-10,000 year half-life that's already beta decaying. The activity level will be high, and it won't decay away very quickly.

 

You probably don't do this in a reactor because you want those neutrons to induce fission (these would be a poison) and you want to absorb only one neutron; in a reactor you may absorb several.

[npts2020]

I understand how changing the isotope of an element may shorten the half-life but how many elements is that true of? If you have a massive amount of a relatively pure element it might work but refining will be no small task, eg. how hard it is to refine reactor fuels. Seems to me like the details are intentionally few to make it easier to get funding. Almost anyone who can claim to neutralize radioative waste will get money for research right now if they can make their idea for it seem even plausible. This idea might sound good but I will believe it when I see it. Seems just as likely to me that you could neutralize the waste by bombarding it with protons, electrons, or some kind of quark.

[Mr Skeptic]

Well, fusors aren't too expensive or impractical as far as neutron sources go.

 

How many moles of neutrons do you need to neturalize tons of radioactive waste? I'm pretty sure you will need self-sustaining fusion to get that, unless you want to pay for all that energy.

[Pete]

Just encountered an interesting article that suggests a neutron bombardment method might, in a couple of decades, be able to speed the decay of radioactive waste in hundreds of years.

 

http://www.sciencedaily.com:80/releases/2008/09/080922100148.htm

 

If so, this would be a great development, and would enhance nuclear fission as an energy source. Anyone got any further information?

Too bad we can't simply put the radioactive material back where we found it.

[Gilded]

Too bad we can't simply put the radioactive material back where we found it.

 

Well perhaps not the same exact spot but it certainly tends to go back into the ground.