Re: Airborne Uranium -- Summary of Responses

[barberj@m4lp.com (Jerry Barber)]

     David (and Radsafe)
     
     You have your Class D and Class Y chemical forms mixed up.  U308 and 
     UO2 are considered Class Y, UO2F2 etc. are Class D.
     
     Jerry Barber
     Molten Metal Technology
     1000 Clearview Ct.
     Oak Ridge TN 37830
     barberj@m4lp.com


______________________________ Reply Separator _________________________________
Subject: Airborne Uranium -- Summary of Responses
Author:  "David W. Lee" <lee_david_w@lanl.gov> at Internet
Date:    7/24/97 6:24 PM


Group:
     
        Radsafer Mike McNaughton earlier asked about the logic behind the DAC
values in 10 CFR 835, noting that the Class W inhalation DAC value for 
U-238 was 15 times larger than the value for Class Y, and that the Class Y
inhalation DAC value for Pu-239 was 3 times larger than the value for Class W.
     
        The following is a summary from the responses received from Radsafers
Jerry Hunt, Liz Brackett, Otto Raabe, and Vince King.
     
     
        U-238   Class D (UO2; U3O8)
                Class W (UO3; UF4; UCl4)
                Class Y (UO2F2; OU2(NO3)2; UF6)
     
                Organs of Ultimate Deposition:  Sometimes kidney, sometimes
mineralized
(compact) bone
     
                Chemical toxicity typically overrides radiotoxicity for Class D
forms of
U-238. Insoluble (Class Y) forms are removed from the lung more slowly; 
hence, they reside in the lung longer to irradiate lung tissue; thus the 
Class Y inhalation DAC is smaller (implying greater radiological hazard) 
than the value for Class W.
     
        Pu-239  Class Y (all Pu-oxides)
                Class W (all other chemical forms)
     
                Organ of ultimate deposition:  bone surfaces
     
                Since Class W Pu-239 once inhaled would be cleared from the lung
faster
than a Class Y chemical form, Class W will get into the blood sooner and 
transfer to bone surfaces sooner than Class Y.  Thus, the Class W 
inhalation DAC is smaller (implying greater radiological hazard) than the 
value for Class Y.
     
REGARDS  David W. Lee, (lee_david_@lanl.gov); Los Alamos National 
Laboratory, Los Alamos, NM  87545
David W. Lee
Los Alamos National Laboratory
Radiation Protection Services Group (ESH-12) 
PO Box 1663, MS K483
Los Alamos, NM  87545
PH:   (505) 667-8085
FAX:  (505) 667-9726
lee_david_w@lanl.gov