Posted on 08/01/2006 7:30:30 PM PDT by AFreeBird
31 July 2006
A group of physicists in Germany claims to have discovered a way of speeding up radioactive decay that could render nuclear waste harmless on timescales of just a few tens of years. 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 sceptical and believe that the technique contradicts well-established theory as well as experiment.
The leader of the German-based group, Claus Rolfs of Ruhr University in Bochum, is an astrophysicist and made the discovery about alpha decay after replicating the fusion reactions that take place in the centre of stars. Using the university’s particle accelerator he fired protons and deuterons (nuclei containing a proton and a neutron) at various light nuclei. He noticed that the rate of fusion reactions was significantly greater when the nuclei were encased in metals than when they were inserted into insulators. He also observed that the effect is enhanced at lower temperatures (J. Phys. G: Nucl. Part. Phys. 32 489).
Rolfs believed this effect could be explained in simple terms by assuming that the free electrons in a metal act like the electrons in a plasma, as described in a model by Dutch physicist Peter Debye. The lower the temperature of the metal, the closer the free electrons get to the radioactive nuclei. These electrons accelerate positively charged particles towards the nuclei, thereby increasing the probability of fusion reactions.
But Rolfs realized that the reverse reaction might also occur and that free electrons could enhance the ejection of positively charged particles from a nucleus. This would reduce the half-lives of α-decay or β+-decay, and increase half-lives for processes involving electrons (which are repelled by the free electrons within the metal), i.e. β–-decay and electron capture.
The group has investigated this hypothesis by embedding a number of radioactive nuclei inside metals and then cooling the metal to a few degrees kelvin. As expected, they observed a longer half-life for the electron capture of beryllium-7 and shorter half-lives for β+-decay in sodium-22 (Eur. Phys. J. A 28 251) and α-decay in polonium-210. They are now investigating the α-decay of radium-226, a hazardous component of spent nuclear fuel with a half-life of 1600 years. Rolfs calculates that this half-life could be reduced to as little as a year and at the very least to 100 years, and believes that the half-lives of all other hazardous alpha emitters within nuclear waste could be shortened by similar amounts.
"This means that nuclear waste could probably be dealt with entirely within the lifetimes of the people that produce it," he says. "We would not have to put it underground and let our great-great-grandchildren pay the price for our high standard of living."
Rolfs admits that much engineering research needs to be done to convert his idea into practice, but he believes there are probably no insurmountable technical barriers. Other physicists, however, think that the basic idea may be flawed. According to Nick Stone, a nuclear physicist recently retired from Oxford University, physicists have already carried out experiments in which they cooled alpha emitters to 4 K and below, but found no significant changes in their half-lives.
Meanwhile, Hubert Flocard, director of the CSNSM nuclear-physics lab near Paris, believes that Rolfs' model contradicts standard solid-state physics, although he admits that he cannot explain the group's data himself. Rolfs concedes that he needs a more sophisticated theory, but stands by his results. "Nature decides what is right," he says.
Edwin Cartlidge is News Editor of Physics World
Saw this over on /. thought I'd ping for comment.
Old saw goes: To eliminate nuclear waste, just put five points in it and give it to Merrill Lynch. It will be gone 15 minutes after the market opens.
LOL! The old "Pump & Dump"!
So where does the energy go?
I will read the article later. I have a better idea regardless. Get a big butter knife and spread it on the middle east.
This is a far better ultimate solution than those daffy schemes for shooting waste into the Sun.
(have to admit I stole the idea from the solar project in Oz)
Gun Laying would be necessary to insure we don't hit Venus or Mercury.
LOL
I read a sci-fi story where waste been shot onto the moon...and that is part of the plot.
Problem of nuc-waste was solved long ago, but it makes the hot fusion community look bad, that's why the hatred and malice towards Cold Fusion/LENR, emanating from MIT/Charles Vest(GWB's science advisor)and their DOE. Stan Gleason in cincinnati invented, in the corner of a welding shop, a process that transmutates thorium to copper and titanium isotopes in 3 hours : a zirconium pipe 3" in diameter, 4 " long, with end caps. Central stainless steel rod with stainless steel disc at middle. 3KWH input. 90%nitric acid, 10% thorium. In 3 hours 90% of the thorium is gone, and the detrius at the bottom shows VISIBLE copper flakes. This is but one of many CF techniques, but you'll never hear about it in the media controlled by uknowwho.
Have you heard of this?
If the rate of decay can be doubled, the halflife will be reduced, and if the hotter material is still not so hot as to be beyond the means of handling as waste, it would bring the material to a safer state sooner. Whether 1000 years to a nearly inert state is really any better than 100,000 years is another question.
Wasn't that the plot of SPACE: 1999? Or maybe Moonbase?
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