Accelerating radioactive decay

[sphenisc]

Can any of you physicists provide more details on this? Is it too good to be true?

http://www.iop.org/Media/Press Releases/press_6762.html

 

[CyCrow]

I'm not a physicist, but even if their theory is true, I doubt it would be practical. The energy requirements would be huge, as decay produces heat that must be removed. Radium-226 isn't much of a problem anyway, it's not a significant part of spent nuclear fuel, but it occurs naturally as part of the Uranium decay series. We already have the technology to make reactors that "burn" all the long-lived fission products to produce only short-lived waste.

// CyCrow

 

[Ririon]

I was not aware that you could change the half-life much. That process happens in the nucleus of the atom, so electrons should have very little to do with it, since they are relatively far away. I assume that "ultra-low temperatures" refers to temperatures at or below liquid helium (4 K). That gets expensive on an industrial scale. That cost would have to be compared to encasing and burying stuff "forever" or using different types of reactors. But the science in itself is rather interesting. Radiation increasing by a factor 100 should be easy to detect, and the tecnology to cool small samples to these temperatures is well-known and widespread, so any results should be out soon.

 

[Cuddles]

Mentioned in this thread. As I said there, the claims about fusion are believable, but the claims about radioactive decay seem unlikely, and should have already been observed.

From here

Nick Stone of Oak Ridge National Laboratory in Tennessee. If alpha decay rates could really be changed as radically as Rolfs suggests, we'd already know about it, he adds. For more than four decades his group has studied the decay of many radioisotopes, including the alpha emitter radium-224, in iron chilled to a whisker above absolute zero. They did this to test fundamental theories about how radioisotopes decay when aligned by strong magnetic fields experienced by trace nuclei surrounded by cold iron atoms. If there had been dramatic changes in alpha decay rates at low temperatures, they should have stuck out like a sore thumb during the checks and balances in his experiments, he says. "Either we've been totally asleep, or this huge change in alpha decay rates just isn't there."

 

[Matabiri]

Science by press release?

One technique that I know has been discussed at length is putting fission waste into the path of fusion-emitted neutrons, to bump low-lived radioactive nuclei onto a faster decay path. So a fusion reactor would not only produce cleaner energy, it could help clean up after fission power...

 

[RichardR]

Entirely unnecessary - Madonna can already make nuclear waste safe with Kabbalah water!

 

[Schneibster]

Stranger things have happened, but I'm having a lot of trouble seeing how supercooling radioactive atoms is going to have any effect on their half-lives. It has an effect on fusion because fusion happens between atoms; but radioactive decay involves only a single nucleus. Why should it matter how much kinetic energy the atom that nucleus is part of has?

 

[GodMark2]

Stranger things have happened, but I'm having a lot of trouble seeing how supercooling radioactive atoms is going to have any effect on their half-lives. It has an effect on fusion because fusion happens between atoms; but radioactive decay involves only a single nucleus. Why should it matter how much kinetic energy the atom that nucleus is part of has?

The energy of the nucleus might matter if the increase in fission wasn't due to an increase spontaneous fission, but due to a chain reaction. I can imagine a scenario where cooling the atoms might enable some of the neutron's that would normally glance off another nucleus would become captured. But that effect would seem to be several orders of magnitude lower than the 100X that the OP study is claiming.

The refuting study mentioned Iron in particular. Do we know what metal the OP study was using for the casing? Could supercooling cause a material to become a better neutron reflector (which could lead to chain reactions at much less than 'critical mass')?

In short: Interesting study, needs to be replicated. If it is, then we have a lot of questions to ask.

 

[Dilb]

The energy of the nucleus might matter if the increase in fission wasn't due to an increase spontaneous fission, but due to a chain reaction. I can imagine a scenario where cooling the atoms might enable some of the neutron's that would normally glance off another nucleus would become captured. But that effect would seem to be several orders of magnitude lower than the 100X that the OP study is claiming.

That wouldn't have any effect. The neutron capture cross section does depend on energy, which then depends on the relative speeds of the neutron compared to the nucleus, but thermal energies are several orders of magnitude too small to matter, plus both the neutrons and atoms are moving randomly anyway, so thermal velocities can add or subtract or anything in between.

Also, Ra-226 is an alpha emitter. You can get neutrons if you mix it with beryllium, but those neutrons come out with ~10 MeV, so they can travel through several cm without hitting anything. Even when they hit something, unless it's a moderator (hydrogen, deuterium or carbon), they'll scatter off with almost all of their energy and continue to not interact with stuff. Plus it's a small number of neutrons anyway: in a typical Ra-Be reactor you can expect about 1 neutron for every 1000 radium decays.

 

[politas]

Stranger things have happened, but I'm having a lot of trouble seeing how supercooling radioactive atoms is going to have any effect on their half-lives. It has an effect on fusion because fusion happens between atoms; but radioactive decay involves only a single nucleus. Why should it matter how much kinetic energy the atom that nucleus is part of has?

Well, exactly what is it that causes radioactive decay? There must be some process occuring inside and/or around the nucleus that leads to it.

 

[Soapy Sam]

Why?

 

[GodMark2]

But that effect would seem to be several orders of magnitude lower than the 100X that the OP study is claiming.

... but thermal energies are several orders of magnitude too small to matter

We're not really disagreeing here.

Also, Ra-226 is an alpha emitter. You can get neutrons if you mix it with beryllium, but those neutrons come out with ~10 MeV, so they can travel through several cm without hitting anything. Even when they hit something, unless it's a moderator (hydrogen, deuterium or carbon), they'll scatter off with almost all of their energy and continue to not interact with stuff. Plus it's a small number of neutrons anyway: in a typical Ra-Be reactor you can expect about 1 neutron for every 1000 radium decays.

I kew you could get neutrons, I didn't remember the energy for those neutrons. Yes, at 10MeV, very little could be done to slow them down. I guess we now wait until someone replicates the experiment before spending much time on it.

 

[Ziggurat]

Well, exactly what is it that causes radioactive decay? There must be some process occuring inside and/or around the nucleus that leads to it.

From a quantum mechanics standpoint, it's actually fairly simple: the undecayed state nuclei is higher energy than the decayed state nuclei, so there's a finite probability of tunneling from the undecayed state into the decayed state. But that all has to do with nuclear forces, and it's hard to see how thermal differences of the sort mentioned could possibly have any significant affect on this process. If this guy is right, it should be experimentally provable, but I doubt he is.

 

[ingoa]

The original paper can be found here.

To be honest it is a lousy paper. Almost incomprehensible.

What I make out of it is the following.

They have a parametrization for an effect (Debye model) which they tested in one area and then extrapolated to an entire different area. It is like saying: my car goes from 0 to 50 km/h in 5 seconds, from 0 to 100 km/h in ten seconds therefore I am sure in 60 seconds I will reach 600 km/h.

Radioactive decay has been measured for more than a hundred years in almost all thinkable conditions and environments. It is highly unlikely that such a large effect (changing the lifetime of radioactive isotopes) would have gone unnoticed.