Speaker
Description
Uranium waste rock dumps contain residual uranium mineralization and, as a result, the entire uranium decay chain, notably the radioactive gas radon. Due to their high air permeability and large thermal capacity, these dumps naturally facilitate airflow through the stack effect. This thermally induced airflow leads to both spatial and temporal variations in radon gas exhalation at uranium waste rock dumps.
The airflow in these dumps is driven by temperature differences, primarily between the dump's inner structure and the atmosphere. This behaviour can be simplified into two main regimes: winter—gas flows upwards, and summer—gas flows downwards.
To obtain long-term observation of this phenomenon, our study utilizes thermometers placed just below the surface of the waste rock dump. These thermometers are advantageous due to their resistance to harsh environments, inconspicuous nature and small size that allows easier placement between large rocks. The ground surface temperature should follow atmospheric temperature at a location of gas intake and mirrors the internal temperature during at a location of gas outflow. We propose that these measurements can identify the temperature at which gas flow inversion occurs (the change in the flow regime).
We will present results from an in-situ pilot campaign as well as preliminary findings from a long-term in-situ study.