RE: Uranium Analysis

["Fulmer, Philip" <philip.fulmer@cplc.com>]

Joelle,

There are a few avenues of inquiry you may pursue.  First, the chemical
analysis reports the concentration/amount in mass units in all
likelihood while the alpha spec results are in activity units.  To
compare the two, someone had to assume some isotopic mix, which because
of different half-lives of the various isotopes could contribute some
error.  Second, some of the alpha energies for the uranium isotopes are
similar in energy and a given alpha peak may consist of counts from
alpha particles emitted from multiple isotopes.  Again, with different
half-lives for these isotopes, the "true" activity represented by any
given alpha peak may have some error associated with it.  And if this
activity is converted to mass units, the results will differ from a
technique that measures the mass directly.

Any other ideas, anyone?

Philip



__________________________
Philip C. Fulmer, PhD, CHP 
Carolina Power & Light Company
Harris Energy and Environmental Center
3932 New Hill-Holleman Road
P. O. Box 327
New Hill, NC 27562-0327
philip.fulmer@cplc.com
(919) 362-3363      

>Dear Radsafers:
>
>I was recently reviewing a licensee request that delt with Uranium.  In the
>original request, the U content was determined chemically.  We asked
>them to take more samples, and these were analyzed with alpha spec. 
>The second samples showed about twice as much Uranium than the first
>samples.  I called the company to ask them if they had any theories as to
>why this was so.  They said that they had the same question and asked
>their HP consultant.  The consultant told them that it was because of the
>different type of analysis.  The HP said he trusted the alpha spec more
>but that this may just be his HP bias.
>
>What do you people out in HP land know about this?  Is there a reason to
>think that one analysis is more reliable than the other?  Has anyone
>studied this question?
>
>I appreciate any help ya'll can give me.
>
>Joelle Key
>TN-DRH
>jkey@mail.state.tn.us
>