[ RadSafe ] Radiation degrades nuclear waste-containing materialsfaster than expected

[Muckerheide, Jim (CDA)]

>-----Original Message-----
>From: radsafe-bounces at radlab.nl 
>[mailto:radsafe-bounces at radlab.nl] On Behalf Of John A Grant
>Sent: Thursday, January 11, 2007 12:13 PM
>To: ROY HERREN; radsafe at radlab.nl
>
>--- ROY HERREN <royherren2005 at yahoo.com> wrote:
>
>> 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

Well, Weber at PNNL makes the stuff, and isn't in the same "fear-monger"
business as "the Cambridge team" and "earth scientist" Farnan.  He could
even be "just an engineer."

Regards, Jim 

PS:  He IS "just an engineer." :-)  See:
http://www.pnl.gov/fsd/people/fellows_lab/weber_william.stm