specific activity of depleted uranium

["Jim Dunlap" <jim.dunlap@guardian.brooks.af.mil>]

     In 49CFR173.434, the Wt% of U-235 in depleted uranium (DU) = 0.45, and 
     the specific activity (SA) = 5.0 E(-)7 Ci/g.  For U-natural the SA is 
     7.1 E(-)7 Ci/g.  A footnote to that table says these values indicate 
     the activity of U-234 (that) is concentrated during the enrichment 
     process.  I suppose for DU a more appropriately term would be 
     'de-enrichment.' In any event, when I calculate the SA for DU I get  
     get 3.5 E(-)7 Ci/g [0.01 E(-)7 Ci/g for U-235 + 3.34 E(-)7 Ci/g for 
     U-238].  My value for DU is similar to the SA value for U-natural 
     found on page 65 of "Radioactivity in the Environment" by Ron Kathren.
     Should I assume the difference in the 49CFR values and my values are 
     due to U-234.  I'm not sure why my values for DU closely match Ron's.  
     I would an explanation for these differences.  Thanks.    

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