4–7 Nov 2024
LH Hotel Dvořák, Tábor, Česká republika
Europe/Prague timezone

Long term radon monitoring in the Bozkov dolomite caves in the context of the geological situation

Not scheduled
15m
LH Hotel Dvořák, Tábor, Česká republika

LH Hotel Dvořák, Tábor, Česká republika

Hradební 3037, 390 01 Tábor 1
Přednáška Radon a další přírodní zdroje ionizujícího záření Radon a další přírodní zdroje ionizujícího záření

Speaker

Václav Štěpán (CTU FNSPE)

Description

These caves are situated in a Lugian region, in the area geologically called the Krkonoše-Jizera crystalline unit. Carbonate rocks occur in discontinuous streaks and lenses in this area. The lens in which the Bozkov caves were formed is 300 m in length and has a maximum width of about 150 m. The cave is permeated by calcareous and siliceous dolomite lenses from the Silurian age, surrounded by phyletic shales. The bedrock below the underground areas is the major source of radon. The environment of caves is typically characterized by 100% humidity, and the number of aerosol particles is around 102 times lower than outside (but the number of free ions is higher). The concentration of radon in the Bozkov dolomite caves may reach levels tens of thousands Bq/m3. The methodology for effective dose from radon estimation for cave guides is based on integral radon activity concentration measurement cV,Rn (integral RAMARN detectors) and evidence of working hours spent in the underground. Continuous radon measurement has been taking place here since 2003, and the measured concentrations form a complete set of data that was processed for the purpose of estimating and predicting movements in the earth's crust.

Monitoring by integral monitors at basic communication (ventilation) nodes in the cave can also show how in-outside temperature changes affect air mass movements in a given cave, if we have a cave model available. 2 years ago, the continuous measurement was extended to a total of 7 positions in the cave system, and the measurement results allow a better understanding of the cave ventilation. The presented contribution introduces 3D cave system visualization (LiDAR technology), embedded in a geological environment following the results of in situ gamma spectrometry (surface above the cave) and continuous radon activity concentration measured by a set of TSR probes.

Primary author

Co-authors

Dušan Milka Lenka Thinová (CTU FNSPE) Lukáš Loula (GeoSLAM Ltd., Innovation House, Ruddington Fields Business park, Mere Way, Nottingham NG11 6JS, GB) Martin Kaschner (CTU FNSPE) Tomáš Bláha (GeoSLAM Ltd., Innovation House, Ruddington Fields Business park, Mere Way, Nottingham NG11 6JS, GB)

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