Sunday, January 29, 2012

UC Davis Researcher: Sea Water Can Corrode Nuclear Fuel, Forming Uranium Compounds That Could Travel Long Distance

From UC Davis News and Information (1/26/2012; emphasis is mine):

Japan used seawater to cool nuclear fuel at the stricken Fukushima-Daiichi nuclear plant after the tsunami in March 2011 -- and that was probably the best action to take at the time, says Professor Alexandra Navrotsky of the University of California, Davis.

But Navrotsky and others have since discovered a new way in which seawater can corrode nuclear fuel, forming uranium compounds that could potentially travel long distances, either in solution or as very small particles. The research team published its work Jan. 23 in the journal Proceedings of the National Academy of Sciences.

“This is a phenomenon that has not been considered before,” said Alexandra Navrotsky, distinguished professor of ceramic, earth and environmental materials chemistry. “We don’t know how much this will increase the rate of corrosion, but it is something that will have to be considered in future.”

Japan used seawater to avoid a much more serious accident at the Fukushima-Daiichi plant, and Navrotsky said, to her knowledge, there is no evidence of long-distance uranium contamination from the plant.

Uranium in nuclear fuel rods is in a chemical form that is “pretty insoluble” in water, Navrotsky said, unless the uranium is oxidized to uranium-VI — a process that can be facilitated when radiation converts water into peroxide, a powerful oxidizing agent.

Peter Burns, professor of civil engineering and geological sciences at the University of Notre Dame and a co-author of the new paper, had previously made spherical uranium peroxide clusters, rather like carbon “buckyballs,” that can dissolve or exist as solids.

In the new paper, the researchers show that in the presence of alkali metal ions such as sodium — for example, in seawater — these clusters are stable enough to persist in solution or as small particles even when the oxidizing agent is removed.

In other words, these clusters could form on the surface of a fuel rod exposed to seawater and then be transported away, surviving in the environment for months or years before reverting to more common forms of uranium, without peroxide, and settling to the bottom of the ocean. There is no data yet on how fast these uranium peroxide clusters will break down in the environment, Navrotsky said.

Navrotsky and Burns worked with the following co-authors: postdoctoral researcher Christopher Armstrong and project scientist Tatiana Shvareva, UC Davis; May Nyman, Sandia National Laboratory, Albuquerque, N.M.; and Ginger Sigmon, University of Notre Dame. The U.S. Department of Energy supported the project.

Professor Navrotsky says as far as she knows there is no evidence of long-distance uranium contamination from Fukushima I Nuke Plant. I don't think the Japanese government is specifically looking for uranium anywhere outside the plant. They are not even looking for strontium. That doesn't mean it doesn't exist.

The abstract of the paper at PNAS (Proceedings of the National Academy of Sciences of the United States of America):

Uranyl peroxide enhanced nuclear fuel corrosion in seawater

Christopher R. Armstrong, May Nyman, Tatiana Shvareva, Ginger E. Sigmon, Peter C. Burns, and Alexandra Navrotsky

Abstract

The Fukushima-Daiichi nuclear accident brought together compromised irradiated fuel and large amounts of seawater in a high radiation field. Based on newly acquired thermochemical data for a series of uranyl peroxide compounds containing charge-balancing alkali cations, here we show that nanoscale cage clusters containing as many as 60 uranyl ions, bonded through peroxide and hydroxide bridges, are likely to form in solution or as precipitates under such conditions. These species will enhance the corrosion of the damaged fuel and, being thermodynamically stable and kinetically persistent in the absence of peroxide, they can potentially transport uranium over long distances.


(H/T anon reader, gr81)

3 comments:

Anonymous said...

Thanks for posting this. I linked it because I think it proves that there's a lot more going on behind the scenes that we're not aware of, and it underscores the dangers of using a technology that we don't fully understand and can't reliably control.

It should also help to silence the naive fools who overconfidently proclaim that "radiation found in areas without nuclear plants can't be the result of nuclear technology". Who knows how many other radioactive particles are traveling across the planet using means unknown to us?

And you're right - just because they're not aware of the evidence doesn't mean there isn't any... especially if they're not looking or are intentionally trying to hide it.

Anonymous said...

"Doomsday Clock",designed in 1947 with the concern-"the atom bomb would only be the first of many presents from Pandora's box of modern science".

When the scientists at Woods Hole finish their study from this summer maybe they would like to model a clock for the Pacific Ocean.

Plastiki could sail out again to the Garbage Patch and see how the toxic stew is cooking along.

There is no Immediate harm to Human health.
Dilution is the Solution...
Tick-Tock

michael jordan said...

These days fuel prices are increasing.Production of fuel from sea water is one of the latest technology, which is developed by U.S.Naval Research Laboratory.In this sea water converts into jet fuel.Hope this will be helpful to the shipping industry for fuel problems.

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