Naslov
Radon concentration in Đurovića cave (Čilipi, Croatia)

Autori
Radolić, Vanja ; Miklavčić, Igor ; Poje, Marina ; Varga, Maja ; Vuković, Branko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, ostalo

Izvornik
Radon in environment / Mazur, Jadwiga ; Kozak, Krzysztof ; Kobal, Ivan - Krakov : The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 2009, 32-32

Skup
First International conference "Radon in environment"

Mjesto i datum
Zakopane, Poljska, 10.05.2009. - 14.05.2009

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
radon ; Đurovića cave ; effective dose

Sažetak
Đurovića cave is located near the control tower of the Airport Dubrovnik. In last ten years, there were several geomorphological, meteorological, archaeological, palaeontological and biospeleological research campaigns ordered by the airport management who is interested in its use for tourist purposes. The cave is located on a small karst plateau and was formed in the Upper Cretaceous limestone and breccia beds along the fissures which controlled the passage directions as well as inclination. It is a 156 m long simple cave consisting of main passage and chamber called “Dubrovačka Republika” (DR). The depth of the cave is 25 m (129 m above sea level and 49 m above the Konavosko polje level). In geomorphological sense, the youngest part of the cave is the DR chamber formed at the intersection of older and younger (neotectonic) fissure systems. Cave clay, rock debris and large blocks predominate among the cave sediments. The cave itself is also very rich in all kinds of speleothems which is very suitable for tourist use. Because of these characteristics and in respect with similar karstic tourist caves from literature the elevated radon level is expected. Integrated radon measurements by means of track etch detectors (two LR-115 II films per detector cup) were started from October 2008 and are still going on due to determination of seasonal variability. First set of 15 detectors were exposed for 55 days ; ten detectors were placed along main passage while 5 detectors were placed at DR chamber. The four detectors were flooded because the dripping water is abundant in wet season. The obtained radon concentrations were in range from 6.3 to 11.3 kBq m^-3 with average value of 9.0 kBq m^-3 and standard deviation of 1.6 kBq m^-3. There was no difference between radon concentrations in main passage and DR chamber. The applied radon measuring method with two LR-115 II films enable estimation of equilibrium factor between radon and its short-lived progenies and the average value of 0.395 with standard deviation of 0.207 were obtained. These preliminary data, according to dose conversion factors published in ICRP Publication 65 (radon exposure of 1 Bq h m^-3 is equivalent to the effective dose of 3.108•10^-6 mSv) give dose rate in Đurovića cave of 0.028 mSv/h. In order to preserve annual effective dose of workers in cave (future tourist guide) below action level for workplaces (10 mSv) he/she should not be more than 357.5 hours per year in cave.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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