RE: Natural Thorium

[Craig Reed <CReed@novoste.com>]

> -----Original Message-----
> From:	Craig Reed [SMTP:CReed@novoste.com]
> Sent:	Wednesday, May 26, 1999 11:13 AM
> To:	Multiple recipients of list
> Subject:	RE: Natural Thorium 
> 
> Elizabeth,
> 
> Your answer is sufficiently accurate for a geologist in the mineral
> extraction industry (See NRCP 118), but might not be adequate if
> he/she
> is working on a radioactive waste repository or a thorium compound
> processing facility that will accept thorium from all possible DOE/DOD
> operations. 
> 
> As you indicate, natural thorium is the naturally occurring
> distribution
> of thorium isotopes (essentially 100% Thorium by weight.)  For
> example,
> Th-228 in near equilibrium with Th-232, etc.  However, it is possible
> to
> accumulate inventories of thorium (compounds) from various fuel/weapon
> cycle activities that yield Th-232/Th-228 (correction), Th-229 and
> Th-230 in
> significantly different proportions.  Different proportions will yield
> different specific activities depending upon the mixture and would
> present a range of  "doses per mass of intake" (and a complex
> radon/thoron release scenario).
> 
> Craig Reed
> Novoste
> creed@novoste.com
> Tel 770 717 6098 
> 
> > -----Original Message-----
> > From:	Elizabeth Algutifan
> > [SMTP:elizabeth_algutifan@wssrap-host.wssrap.com]
> > Sent:	Wednesday, May 26, 1999 9:46 AM
> > To:	Multiple recipients of list
> > Subject:	Natural Thorium 
> > 
> > This is a question of semantics: What does the term "natural
> thorium"
> > really
> > mean? A geologist colleague of mine came up to me this morning and
> > asked me to
> > tell him the specific activity of natural thorium. As I got to
> > thinking about
> > it, it occurred to me that if natural thorium is only referring to
> the
> > thorium
> > isotopes in the decay chain, I can calculate it based on assuming
> > secular
> > equilibrium between Th-232 and Th-228 (and say they both contribute
> > half to the
> > total nat Th activity). Is that an oversimplification? 
> > 
> > Elizabeth Algutifan
> > Elizabeth_Algutifan@wssrap-host.wssrap.com
> > 
> >
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