RE: Activity ratio of U-238/U-235 in natural uranium

["Bradshaw, Keith" <Keith.Bradshaw@nnc.co.uk>]

Franz, RADSAFE



Using



U-238 238.0508 g/mol, 99.2745 atom%, half-life 1.6319E+12 day

U-235 235.0409 g/mol,  0.7200 atom%, half-life 2.5706E+11 day



I calculated 238U/235U activity ratio to be 21.72 (I didn't get as far as

propagating the uncertainties- the largest relative uncertainties seems to

be the half-lives of U-238, at 0.11%, and U-235 at 0.070%.  The atom %

uncertainties are an order of mag smaller.  The nuclide masses appear to be

known with very great precision- more significant figures than above.  My

guesstimate is an overall uncertainty of 0.03 in the last figure.)



The data comes from Radiochemical Manual (1998).



My own unchecked calculation- no responsibility taken for any mistakes!



Regards



Keith Bradshaw

keith.bradshaw@nnc.co.uk



> -----Original Message-----

> From: Franz Schoenhofer [mailto:franz.schoenhofer@CHELLO.AT]

> Sent: 11 January 2004 21:43

> To: radsafe@list.vanderbilt.edu

> Subject: Activity ratio of U-238/U-235 in natural uranium

> 

> 

> 

> RADSAFErs,

> 

> Is there anybody, who has the activity ratio of U-238/U-235 in natural

> uranium at hand and could quickly tell me? I need it for a 

> review of a paper

> for a scientific journal. (When I emptied my office because 

> of my retirement

> I had to put everything quickly into storage boxes and have 

> not yet emptied

> them!)

> 

> Thanks!

> 

> Franz

> 

> 

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