[ RadSafe ] Advection / Diffusion of Radon through Media

Fri Aug 22 02:24:23 CDT 2008

Some lit.:

Characteristics of soil radon transport in different geological formations
N. M. Ershaidat,  B. A. Al-Bataina, S. A. Al-Shereideh
Environ Geol (2008) 55:29–35
DOI 10.1007/s00254-007-0961-x

Simulation of Radon Transport through Building Materials: Influence of 
the Water Content on Radon Exhalation Rate
F. FOURNIER, J. E. GROETZ; F. JACOB, J. M. CROLET and H. LETTNER
Transp Porous Med (2005) 59:197–214 
DOI 10.1007/s11242-004-1489-0

Iakovleva V. S., Ryzhakova N. K. (2003):
A method for estimating the convective radon transport velocity in soils
Rad. Meas. 36, 389-391

Iskandar D., Oida T., Nakashima S. (xxx): Determination of 222Rn 
Diffusion Coefficient in Japanese Soils.
Irpa 10, P-1b-48

Speelman W . J. (2004): Modelling and measurement of Radon diffusion 
through soil for application on mine tailings dams.
Thesis, University of the Western Cape. (I have it as pdf, if you want 
it. ca. 3 MB)

Thang N. X., Dunf L T., Vuong L. V. (1995):
Radon transport equation in earth's crust.
Rad. Meas. 25 (1-4), 661-3

Holkko J., Liukonnen S. (1992):
Radon diffusion in Finnish glacial till soil
Rad Prot Dos 45 (1-4), 231-3

regards,
p

Dan W McCarn wrote:
> Hello Group:
>
> What I'm really fishing for transport equations for diffusion / advection including 
> time and decay or some papers / pubs that describe the mechanisms.
>
> Dan ii
>
> Dan W. McCarn, Geologist; 3118 Pebble Lake Drive; Sugar Land, TX 77479; USA 
> Home: +1-281-903-7667; Austria-cell:  +43-676-725-6622
> HotGreenChile at gmail.com   mccarn at unileoben.ac.at   UConcentrate at gmail.com
>
>
> From: "Dan W McCarn" <hotgreenchile at gmail.com>
> To: "'Radsafe'" <radsafe at radlab.nl>
> Sent: Wednesday, August 20, 2008 7:18 PM
> Subject: [ RadSafe ] Advection / Diffusion of Radon through Media
>
>
>   
>> Hello:
>>
>> Perhaps this has been done somewhere before:  How does one go about
>> estimating that component of radon that emanates from a granite or other
>> material? There are several factors that I can think of:
>>
>> 1 - Nature of uranium mineralization: a) contained within minerals e.g.
>> zircon, monazite; biotite and b) epigenetic mineralization via solutions
>> precipitating U minerals in pore spaces and fractures.  Most granites show
>> secular equilibrium in the uranium series.  Is this a macroscopic or
>> microscopic property?  Does the 5 MeV or so recoil dislodge the radon that
>> far away from the origin in a mineral grain? Since granites are massive
>> rock
>> bodies, emanation of radon and subsequent decay would / could occur within
>> the same granite, except near the margins.
>>
>> Does the accumulation of alpha decays e.g. U-238, Th-234, U-234, Th-230,
>> Ra-226 ⇒ Rn-222 make it more accessible to mobilization? Because U-234 is
>> more easily leachable than U-238 (Wyoming Basins, Kazakhstan), this
>> suggests
>> to me that the Ra-226 has been fairly well dislocated prior to decay to
>> Rn-222.
>>
>> 2 - Dual porosity matrix - the nature of the permeability associated with
>> fractures or porous fractions of a material vs. that portion that is
>> contained within a mineral grain.  I can imagine that if the rock was
>> porous
>> / permeable enough to be an aquifer, that the radon would advect at the
>> same
>> rate as the water.  This is borne-out by borehole measurements in and near
>> sandstone U deposits.
>>
>> 3 - Distance to a surface (e.g. fracture or actual surface of material)
>>
>> Empirically, does a 1 or 2 cm slab of uniform composition granite emanate
>> at
>> the same rate per unit surface area as a 10 cm slab?
>>
>> Dan ii
>>
>> Dan W. McCarn, Geologist; 3118 Pebble Lake Drive; Sugar Land, TX 77479;
>> USA
>> HotGreenChile at gmail.com   UConcentrate at gmail.com
>>
>>
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>
>
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