[ RadSafe ] Radiation degrades nuclear waste-containing materials faster than expected

[John A Grant]

--- ROY HERREN <royherren2005 at yahoo.com> wrote:

>     bV = parseInt(navigator.appVersion);  if (bV >=
> 4) window.print();    
> http://www.physorg.com/news87657811.html
>    
>              Radiation degrades nuclear
> waste-containing materials faster than expected     
> Minerals intended to entrap nuclear waste for
> hundreds of thousands of years may be susceptible to
> structural breakdown within 1,400 years, a team from
> the University of Cambridge and the Pacific
> Northwest National Laboratory reported this week in
> the journal Nature.     
> The new study used nuclear magnetic resonance, or
> NMR, to show that the effects of radiation from
> plutonium incorporated into the mineral zircon
> rapidly degrades the mineral's crystal structure. 
> 
> This could lead to swelling, loss of physical
> strength and possible cracking of the mineral as
> soon as 210 years, well before the radioactivity had
> decayed to safe levels, said lead author and
> Cambridge earth scientist Ian Farnan. 
> 
> According to current thinking, highly radioactive
> substances could be rendered less mobile by
> combining them, before disposal, with glass or with
> a synthetic mineral at a very high temperature to
> form a crystal. 
> 
> However, the crystal structure can only hold the
> radioactive elements for so long. Inside the crystal
> radioactive decay occurs, and tiny atomic fragments
> called alpha particles shoot away from the decaying
> nucleus, which recoils like a rifle, with both types
> repeatedly blasting the structure until it breaks
> down. 
> 
> This may increase the likelihood for radioactive
> materials to leak, although co-author William J.
> Weber, a fellow at the Department of Energy national
> laboratory in Richland, Wash., who made the samples
> used in the study, cautioned that this work did not
> address leakage, and researchers detected no
> cracking. Weber noted that the "amorphous," or
> structurally degraded, natural radiation-containing
> zircon can remain intact for millions of years and
> is one of the most durable materials on earth. 

The above paragraph disagrees with the rest of the
report.

John Grant