[ RadSafe ] Advection / Diffusion of Radon through Media

[Emer, Dudley]

Dan,
Sorry for the late response as I'm playing email catch-up after beginning deployed to the hurricanes for 3 weeks with FEMA US&R.

We've done some 1-D modeling here at the test site on the advective and diffusive transport of radon in alluvium that may help.  The model is CASCADER which is a gas-phase isothermal 1-D fate and transport model using Bateman m-chain rules for radionuclide decay in dry soils.  It contains both barometric pressure induced advection and diffusion with reversible and irreversible sorption for each radionuclide.

CASCADER: An M-Chain Gas-Phase Radionuclide Transport and Fate Model, Volume 1 - Basic Physics and Mathematics;
Lindstrom, F.T., Cawlfield, D.E., Emer, D.F., Shott, G.J., Donahue M.E.; June 1992; DOE/NV/10630-23

CASCADER: An M-Chain Gas-Phase Radionuclide Transport and Fate Model, Volume 2 - Users Manual for CASCADR8;
Cawlfield, D.E, Been, K.B., Emer, D.F., Lindstrom, F.T., Shott, G.J.; June 1993; DOE/NV/10630-57.

CASCADER: An M-Chain Gas-Phase Radionuclide Transport and Fate Model, Volume 3 - Heterogeneous Layered Porous Media;
Lindstrom, F.T., Cawlfield, D.E., Emer, D.F., Shott, G.J., Donahue M.E.; February 1993; DOE/NV/10630-41.

CASCADER: An M-Chain Gas-Phase Radionuclide Transport and Fate Model, Volume 4 - Users Guide to CASCADR9;
Cawlfield, D.E., Emer, D.F., Lindstrom, F.T., Shott, G.J.; September 1993; DOE/NV/10630-63.

A Simulation of the Transport and Fate of Radon-222 Derived from Thorium-230 Low Level Waste in the Near-Surface Zone of the Radioactive Waste Management Site in Area 5 of the Nevada Test Site; Lindstrom, F.T., Cawlfield, D.E., Emer, D.F., Shott, G.J., December 1993; DOE/NV/10630-58.


Regards,

Dudley Emer
Geophysicist
National Security Technologies
702-295-7808 office
702-794-5824 pager
702-521-8577 cell

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf Of Dan W McCarn
Sent: Thursday, August 21, 2008 12:32 PM
To: 'Radsafe'
Subject: RE: [ RadSafe ] Advection / Diffusion of Radon through Media

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
>
>
> _______________________________________________
> You are currently subscribed to the RadSafe mailing list
>
> Before posting a message to RadSafe be sure to have read and understood
> the RadSafe rules. These can be found at:
> http://radlab.nl/radsafe/radsaferules.html
>
> For information on how to subscribe or unsubscribe and other settings
> visit: http://radlab.nl/radsafe/
>


_______________________________________________
You are currently subscribed to the RadSafe mailing list

Before posting a message to RadSafe be sure to have read and understood the RadSafe rules. These can be found at: http://radlab.nl/radsafe/radsaferules.html

For information on how to subscribe or unsubscribe and other settings visit: http://radlab.nl/radsafe/