Radon data processing and outputs for the needs of the State Office for Nuclear Safety (according to the Czech Radon Programme)

Much of the population living in the Czech Republic is exposed to radiation from natural sources, especially to the
radon effect. The aim of geological research defined by the State Office for Nuclear Safety (SONS) was to detect
areas with estimated high radon concentration in soil gas. A uniform method of measurements and uniform methodology
of radon risk category assessment of geological units and a centralized radon database was established. Radon
risk classification was based on statistical evaluation of soil gas radon concentration and permeability in investigated
geological units. Prognostic radon risk maps in various scales were the main outputs of this research. With the
help of GIS tools spatial analyses were found a correlation between soil gas radon values in selected geological units
and indoor measurements in dwellings. After verification of the efficiency of track etch detectors placed in dwellings
with the help of prognostic maps 75% reliability of these maps was proven. This reliability of analyses induced the
SONS to widely use radon risk maps to determine areas with predicted high radon risk category.