RE: DU -- FYI

["Heinmiller, Bruce" <heinmillerb@aecl.ca>]

Natural uranium ORE contains the nuclides listed below.  Natural uranium
(that is, elemental uranium with the natural isotopic abundance) does not.
However, the canonical value of 2.2 mGy/h for a contact dose rate from a
natural uranium slab assumes that the relatively-short-lived Th-234,
Pa-234m, and Th-231 have grown in since chemical separation of the uranium.
If someone hands you a piece of what they refer to as natural uranium, I
think it's generally assumed that it contains three isotopes of uranium in
their natural isotopic abundance as well as (unless it's very freshly
separated) the three nuclides listed above, and nothing else of
significance.  The other nuclides end up in the tailings from the mill.

Bruce Heinmiller
heinmillerb@aecl.ca

> ----------
> From: 	Bernard L Cohen[SMTP:blc+@pitt.edu]
> Reply To: 	radsafe@romulus.ehs.uiuc.edu
> Sent: 	Monday, May 17, 1999 9:42 AM
> To: 	Multiple recipients of list
> Subject: 	RE: DU -- FYI
> 
> 
> On Fri, 14 May 1999, Heinmiller, Bruce wrote:
>         > 
> > For example, the statement that DU is much less radioactive than Unat.
> The
> > U-235 chain is unimportant in the context of activity of either Unat or
> DU,
> > so Unat comprises principally four nuclides (unless it's exceedingly
> fresh)
> > of nominally equal activity, and DU comprises the same activity of the
> first
> > three of these (unless it's exceedingly fresh), plus a small quantity of
> the
> > remaining U-234.  If you looked at both Unat and DU with a G-M pancake
> > detector you'd be hard-pressed to differentiate between the two, because
> > almost everything you're seeing is the same Pa-234m in each case.  With
> > regard to doses from potential intakes, the activity of alpha emitters
> (the
> > uranium isotopes) in DU is nominally half that of the same mass of Unat.
> 
> 	--Natural uranium contains Th-230, Ra-226, Rn-222, Po-218, Po-214,
> and Pb-210, all alpha emitters, not to mention lots of beta and gamma
> emitters (eg Bi-214, Pb-214), which would be absent in DU.
> 
> 
> 
> 
> 
> Bernard L. Cohen
> Physics Dept.
> University of Pittsburgh
> Pittsburgh, PA 15260
> Tel: (412)624-9245
> Fax: (412)624-9163
> e-mail: blc+@pitt.edu
> 
> 
> 
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
> 
************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html