Theoretical considerations regarding the migration of {sup 222}Rn and {sup 220}Rn from uranium- and thorium-bearing underground environments
- Elliot Lake Lab., Elliot Lake, Ontario (Canada)
Theoretical calculations are presented for partially enclosed uranium- and thorium-bearing subterranean environments, such as tunnels and underground uranium mines. The variables of practical interest considered here are the {sup 222}Rn and {sup 220}Rn concentrations in the wall, and the flux densities of the same radioactive gases in the wall and at the wall/air interface of these underground sites. Calculations have been conducted based on a plane, semi-infinite geometry model (commonly used to predict radiation levels in mines) and a cylindrical (i.e., tunnel) geometry model. The {sup 220}Rn flux density, J({sup 220}Rn), calculated according to the plane and cylindrical geometries agree with each other within 5% for wall media of porosity equal to or greater than about 2%, even for tunnels of small radii. However, for {sup 222}Rn the cylindrical geometry gives values for the {sup 222}Rn flux density, J({sup 222}Rn), substantially higher (by a factor of 1.4 to {approximately}3) than those predicted by the plane semi-infinite geometry. A practical difficulty arises in the experimental verification of the models in underground environments. The results are relevant for predicting radioactivity levels ({sup 222}Rn, {sup 220}Rn, and their progeny) in underground environments such as uranium mines. 34 refs., 8 figs.
- OSTI ID:
- 54545
- Journal Information:
- Health Physics, Journal Name: Health Physics Journal Issue: 1 Vol. 67; ISSN HLTPAO; ISSN 0017-9078
- Country of Publication:
- United States
- Language:
- English
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