[ RadSafe ] pyrophoric uranium considered nonessential

[Otto G. Raabe]

At 10:05 PM 7/6/2005, James Salsman wrote:

>The temperature of a particle suspended in air has no bearing on
>whether or not it can be inhaled.  That is beside the point.
>
>After being thrust into air by a fire, a molecule of UO3(g) is not
>likely to collide with more than a few dozen other UO3(g) particles,
>and not likely to glom onto any of them until it has had a chance
>to cool, and further diffuse into air.  Based on detection patterns
>-- from http://www.bovik.org/du/Salbu-uranyl-detected.pdf and Dr.
>Johnson's and his colleagues' work -- UO3 readily plates on surfaces
>(and therefore lung tissue, where all particles smaller than 0.01
>microns are absorbed into the bloodstream immediately), but does not
>fall to the ground with the U3O8 and UO2 combustion product dusts
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Apparently Mr. Salsman never studied aerosol science, and seems to think 
his imagination defines aerosol behavior. The facts concerning the actual 
characteristics of DU aerosols including UO3 and the actual biological 
risks thereof are well described 
in:  http://www.gulflink.osd.mil/du_ii      It is clear that the actual 
risks are minimal, and limited to kidney damage associated with really 
immense systemic intakes.

Airborne monomeric UO3 is not a gas at room temperatures and would 
agglomerate and/or attach quickly to other airborne dust particles and 
surfaces. The study by Salbu et al. (2205) that is referenced clearly 
refers to "UO3 particles". Although, UO3 is more readily absorbed into the 
blood than other oxides of uranium, its abundance under real conditions is 
apparently minimal.

Otto


**********************************************
Prof. Otto G. Raabe, Ph.D., CHP
Center for Health & the Environment
(Street Address: Bldg. 3792, Old Davis Road)
University of California, Davis, CA 95616
E-Mail: ograabe at ucdavis.edu
Phone: (530) 752-7754   FAX: (530) 758-6140
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