Measurements on, and modelling of diffusive and advective radon transport in soil

Results are presented of measurements on radon transport in soil under controlled conditions with a laboratory facility consisting of a stainless steel vessel (height and diameter 2 m) filled with a uniform column of sand. At several depths under the sand surface, probes are radially inserted into the vessel to measure the radon concentration in the soil gas.

To study advective radon transport a perforated circular box is placed in the sand close to the bottom of the vessel. By pressurising this box, an air flow through the sand column is induced. Radon concentration profiles were measured without an air flow as a function of time, and for several values of the air flow, equilibrium radon concentration profiles were measured.