Halving Half Lives

An anonymous reader writes "PhysicsWeb is reporting that German scientists may have found a way to significantly reduce the radioactive decay time of nuclear waste. This could render the waste harmless in just tens of years and make disposal much less difficult as opposed to current standards. From the article: 'Their proposed technique - which involves slashing the half-life of an alpha emitter by embedding it in a metal and cooling the metal to a few degrees kelvin - could therefore avoid the need to bury nuclear waste in deep repositories, a hugely expensive and politically difficult process. But other researchers are skeptical and believe that the technique contradicts well-established theory as well as experiment.'"

Comments

Um

[Geoffreyerffoeg]

Is this wise? Decreasing the half-life means increasing the radioactivity. Given the option of living near a nuclear waste site and living near the lab where this is performed, I'd choose the former....

In order to get the radiation down to safe levels, you have to out-radiate everything up to that level. Same radiation, doesn't matter if it takes the normal amount of time or less.

Re:Um

[Anonymous Coward]

True, but it's easier to contain the radiation for a short time then to design a system to contian it for a long time.

Re:Um

[LWATCDR]

Actually yes it is wise.
It is easy to shield high level waste. Water will work just fine. If you only have to store it for a few years then it really becomes a simple problem.
The sad thing is I doubt that this could work they way the say it will. It really needs to be tested.
I could understand if they used a good neutron emitter like beryllium. When an Alpha particle hits that you get neutrons. The neutrons could then cause an increase in decay type reactions, if it was captured by a nuclei of the the substance that you wanted to degrade. Even that is a big maybe since I am just thinking of ways it could work without doing any math.
Even then it seems like you wouldn't get anything like what this guy is claiming.

Re:Um

[gardyloo]

Is this wise? Decreasing the half-life means increasing the radioactivity. Given the option of living near a nuclear waste site and living near the lab where this is performed, I'd choose the former....

    You're right. But (as other posters have said) it is [probably] a good tradeoff. In my laboratory, we use ozone to purify water (read: kill bad things therein). It's nasty stuff, but it's so reactive (therefore lethal to buggies) that it disappears really fast. We used to use chlorine, which wasn't nearly so nasty, but which stuck around for much, much longer than the ozone. If you can deal with the reactivity during the worst of the reaction (at the very beginning), then you're pretty much home-free. Constant exposure to low-level chemicals (or radioactivity) which you might not know about is most likely much worse than very quick exposure to high levels of the same stuff which you DO know about.

Re:Um

[RoffleTheWaffle]

That's actually the idea - to make radioactive substances even more radioactive under controlled conditions so as to decay them into safer forms over a much shorter period of time, decreasing the amount of dangerously radioactive waste that has to be disposed of. Sure, it becomes more radioactive, but only under specific conditions and within a small timespan.

I just think it's a shame the Integral Fast Reactor project got canned back in Clinton's day. If it hadn't been shut down, maybe nuclear waste wouldn't be nearly as huge a problem now...

Re:Um

[MindStalker]

Couldn't you simply put it back into productions. I mean if its emitting all this excess radiation could you..... produce power with it????

Energy-balance?

[rainer_d]

I haven't read the article, but doesn't cooling things to a few K consume a sizeable amount of energy?

Even if this works, it will be tough.

[Animats]

Even if this works, it will be tough to use. You'll have to cool something that emits heat down to near absolute zero. The energy required for that refrigeration job will be greater than the heat energy the radioactive material will emit over its remaining decay life.

Re:Kerning

[rrohbeck]

How do these Germans know so much about the atomic nucleus? Did Neils Bohr leave them a working model or something?

Easy: General education level, good science classes in high school, social image/reputation of science and scientists, and an absence of religious bias against science.

Niels Bohr was Danish, FWIW.

d00d!

[Black Parrot]

> you slow down an atom to near absolute zero, you would be lengthening the half-life, say from 200,000 years to 400,000 or whatever, because the binding energy would stay the same, just the ability of the particles to break free would be reduced because of the slowed movements between the particles. you might even generate a spike in atomic activity when it warms up.

FYI, radioactive decay isn't caused by thermal energy. Notice the lack of a term for temperature in the relevant equations.

> how does some of what passes for scientific papers get accepted, anyway? box tops? there's a lot of stuff that the mass media picks up on and publicizes that just can't stand the smell test.

One might ask a similar question about Slashdot moderation.

Too Expensive to Measure

[Doc Ruby]

This development is encouraging, though of course not immediately useful. Because storing radioactive masses in even more metallic mass down near 0K for a century or more sounds like it consumes a vast amount of energy. Maybe more energy than the fuel produces while it's useful in reactors. Add the cost of building, securing and maintaining the nuke plant and its "detox" coolers, and nuke power still looks like a loser.

But there's scientific hope for better engineering that could change that. The extra energy more quickly removed from the spent fuel in this process could possibly be harnessed. That would mean that nuclear fuel not only is made safe in manageable durations, like less than a century, but more of its potential energy is available right away, or during the lifetime of its "soft landing". The combination of greater efficiency and closed-ended management does transform at least that part of nuclear's currently unacceptable cost basis.

As long as we're redesigning these reactions, we should do it all in space. There's plenty of microtemperatures out there; microgravity can make operations more energy efficient; security is less fuzzy; accidents have less exposure to vulnerable facilities, ecosystems and organisisms. It's still risky and expensive transporting fuel out of Earth's gravity well, but that's a lot more addressable by failsafe engineering than terrestrial proliferation.

Re:why bury it all?

[The Snowman]

Keep in mind that you aren't going to load up a rocket to full capacity with nuclear waste. You need to contain it somehow, preferably in multiple boxes that will protect it in case of an accident on launch (or at least until it escapes Earth's gravity and the Sun's gravity takes over). Even then you're better off not loading it to capacity anyway, to make very sure you have enough lift and fuel to achieve its mission.

Also keep in mind that as far as I know all of our launch vehicles are designed to carry payloads into orbit, not all the way to the sun. Yes, we launch stuff to Mars and other planets, but not to the Sun. We would have to design and test a launch vehicle (even if just a second stage vehicle that would go from orbit to the Sun) specifically for the task at hand.

Finally, we have a large backlog of waste material that needs to go as well. This means more rockets to get the job done, which means more money. This also assumes we can't recycle some of the waste, which is a very real possibility.