Speaker
Description
Radiation protection in underground workplaces, such as minning tunnels, requires systematic monitoring of occupational exposure. Workers are exposed not only to external gamma radiation originating from surrounding rock, but also to radon and its short-lived progeny present in the air. At established workplaces, monitoring strategies typically combine personal dosimetry with ambient measurements.
In addition to routine monitoring, the determination of ambient dose equivalent H(10) using portable survey instruments is an essential part of operational radiation protection and the characterization of newly explored underground spaces. In environments with elevated radon concentrations, however, the interpretation of H(10) measurements becomes non-trivial. A key question is the relative contribution of gamma radiation from the rock mass versus that arising from decay of radon progeny deposited on surfaces or attached to aerosol particles in air.
This study combines Monte Carlo simulations with experimental measurements performed in selected underground environments as well as in controlled experimental enviroment. The simulations allow systematic investigation of different tunnel geometries and enable parametric analyses for varying radon concentrations, equilibrium factors, unattached fractions, and activity concentrations of naturally occurring radionuclides (particularly from the uranium decay series) in the surrounding rock. The experimental data are used to validate the simulation approach and to assess the consistency between modeled and measured ambient dose equivalent values. The results provide guidance for interpreting field measurements and for optimizing radiation monitoring strategies in high-radon underground environments.