Re[2]: Uranium Uptake Above 10 CFR 20 Limit

[Rodney Bauman <rodney_bauman@wssrap-host.wssrap.com>]

W. A. Lorenzen wrote:

>Is to possible to exceed a committed dose limit from a
>regulatory standpoint for a class Y material before
>any nephrotoxic limit is reached?

Answer = YES

For insoluble uranium compounds, an individual will exceed applicable TEDE/TODE
limits prior to exceeding kidney protection mass action levels.

Also, for soluble uranium compounds enriched to greater than 5% U-235 (by
weight), the radiological limits are more limiting than the kidney protection
limits.  This is due to the corresponding increase in uranium's specific
activity (primarily due to the increase in U-234 concentrations).

>What is the committed dose from an inhalation intake of 29 mg of >class Y
uranium (assume 1 micron particle size)?

This calculation is very dependent upon the uranium's enrichment.  For example,
due to its lower specific activity, depleted uranium will give approximately 1/2
the CEDE/CDE of normal enriched uranium.  However, if this intake was assumed to
consist of normal enriched Class-Y uranium, then using FGR #11 and a specific
activity of 2.5 E4 Bq/g, the following doses are obtained:  CEDE ~ 2,500 mrem
and CDE to the lung ~ 20.8 rem.

Rodney Bauman, CHP, RRPT
rodney_bauman@wssrap-host.wssrap.com


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