[ RadSafe ] Fwd: Rn-222 from Depleted Uranium

Chris Alston achris1999 at gmail.com
Tue Aug 20 14:25:40 CDT 2013


There is no radon, because there is no radium.  If you take a look at
the half-lives of the daughters (sorry, *progeny*) intermediate
between U-238 and Ra-226, you will see that it takes near-geological
time to reach even 50% secular equilibrium, never mind >99%.


---------- Forwarded message ----------
From: Andrew McGechaen <A.McGechaen at buffaloinspection.com>
Date: Tue, Aug 20, 2013 at 2:18 PM
Subject: [ RadSafe ] Rn-222 from Depleted Uranium
To: "radsafe at health.phys.iit.edu" <radsafe at health.phys.iit.edu>

Dear Sir/Madam,

My building stores about 300kg of depleted uranium. I have read that
the indoor radon hazard in buildings originates from decay products of
uranium in soil. Checking the Radium Series, I noted U-234 (245500a)
-> Th-230 (75380a) -> Ra-226 (1602a) -> Rn-222 (3.8235d), with the
attached half-lives. Fetter and von Hippel (1997) give U-234 at a
concentration of 7 ppm in DU.

Is it safe to ignore the decay chain of U-238 to U-234, and consider
only the initial concentration of U-234 ?

Is it realistic to assume that the residue of Ra-226 in the DU would
be zero after chemical refinement?

I assume the U was depleted and chemically refined years or decades
ago. What activity of Rn-222 would exist now?

Might radon escape through cracks or communicating voids in the
metallic uranium?

Might any appreciable quantity of radon escape from the uranium metal
by Fickian diffusion?
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