Radon dose calculation methodology for underground workers in the Czech Republic.

The project focused on classifying the level of irradiation from natural ionising radiation sources for workers in publicly accessible caves and in caves used for speleotherapy, with applicability to other underground workplace. A correct and accurate procedure (and calculation) is defined for determining the effective dose that workers are exposed to in caves, based on the results of integral measurements of radon volume activity and on the length of time spent by workers in the caves. A review was made of various approaches for evaluating lung irradiation found in the literature. Experimental measurements of cave atmosphere characteristics (continuous measurement of radon volume activity, continuous and integral measurements of radon decay products, interior climatic parameters and aerosol spectra) were the main sources for the methodology.