Radon-222 signatures of natural ventilation regimes in an underground quarry

Perrier, Frédéric; Richon, Patrick; Crouzeix, Catherine; Morat, Pierre; Mouël, J. L. Le

doi:10.1016/s0265-931x(03)00117-6

Cited by 73 publications

(54 citation statements)

References 30 publications

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“…residence time) (Faimon et al, 2011). According to Wilkening and Watkins (1976) and Perrier et al (2004), the temporal evolution of radon concentration at a given location in the cave can be described as…”

Section: Estimation Of Radon Sourcementioning

confidence: 99%

“…Radon ( 222 Rn, α-radioactive, half-life t 1/2 = 3.82 days) has often been used as an excellent tracer for air circulation, since it is a noble gas and highly abundant in caves (Cigna, 2003;Cunningham and Larock, 1991;Hakl et al, 1996Hakl et al, , 1997Kies and Massen, 1997;Kowalczk and Froelich, 2010;Perrier et al, 2004;Przylibski, 1999). Its half-life, suitable for the timescales on which cave ventilation takes place, distinguishes 222 Rn from the other two radon isotopes ( 220 Rn and 219 Rn).…”

Section: Introductionmentioning

confidence: 99%

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Reasons for large fluctuation of radon and CO<sub>2</sub> levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)

Gregorič¹,

Vaupotič

Gabrovšek

2013

Nat. Hazards Earth Syst. Sci.

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Abstract. Measurements of radon concentration were performed at three geomorphologically different locations in Postojna Cave, Slovenia. In the part of the cave open to visitors, annual average radon activity concentrations of 3255 ± 1190 Bq m−3 and 2315 ± 1019 Bq m−3 were found at the lowest point (LP) and in the Lepe jame (Beautiful Caves, BC), respectively. A much higher average of 25 020 ± 12 653 Bq m−3 was characteristic of the dead-end passage Pisani rov (Gaily Coloured Corridor, GC), in which CO2 concentration also reached very high values of 4689 ± 294 ppm in summer. Seasonal variations of radon and CO2 levels in the cave are governed by convective airflow, controlled mainly by the temperature difference between the cave and the outside atmosphere. The following additional sources of radon and CO2 were considered: (i) flux of geogas from the Earth's crust through fractured rocks (radon and CO2 source), (ii) clay sediments inside the passage (radon source) and (iii) the soil layer above the cave (radon and CO2 source).

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Section: Estimation Of Radon Sourcementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reasons for large fluctuation of radon and CO<sub>2</sub> levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)

Gregorič¹,

Vaupotič

Gabrovšek

2013

Nat. Hazards Earth Syst. Sci.

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“…The first is the aspect of radiation protection (Duenas et al, 1999; Correspondence to: A. Gregorič (asta.gregoric@ijs.si) al., 1984;Kávási et al, 2010;Vaupotič, 2008) and the second that of radon as a tracer for air movement within a cave (Cunningham and Larock, 1991;Hakl et al, 1996;Kies and Massen, 1997;Kowalczk and Froelich, 2010;Perrier et al, 2004;Przylibski, 1999). Minute quantities of uranium ( 238 U) present in limestone result in relatively high values of radon in karstic caves (Cigna, 2005;Gillmore et al, 2002;Hakl et al, 1997) due to the low natural ventilation of the underground cavities.…”

Section: Introductionmentioning

confidence: 99%

Dependence of radon levels in Postojna Cave on outside air temperature

Gregorič¹,

Zidanšek²,

Vaupotič

2011

Nat. Hazards Earth Syst. Sci.

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Abstract. Postojna Cave is the largest of 21 show caves in Slovenia. The radon concentration there was measured continuously in the Great Mountain hall from July 2005 to October 2009 and ranged from about 200 Bq m −3 in winter to about 3 kBq m −3 in summer. The observed seasonal pattern of radon concentration is governed by air movement due to the difference in external and internal air densities, controlled mainly by air temperature. The cave behaves as a large chimney and in the cold period, the warmer cave air is released vertically through cracks and fissures to the colder outside atmosphere, enabling the inflow of fresh air with low radon levels. In summer the ventilation is minimal or reversed and the air flows from the higher to the lower openings of the cave. Our calculations have shown that the effect of the difference between outside and cave air temperatures on radon concentration is delayed for four days, presumably because of the distance of the measurement point from the lower entrance (ca. 2 km). A model developed for predicting radon concentration on the basis of outside air temperature has been checked and found to be successful.

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“…While there is no correlation with the distance from the floor, or to the nearest wall, smaller annual variations are observed at the points most remote from the main access pit (point number 6). This suggests that natural ventilation (Perrier et al, 2004) may be dominating the amplitude of the annual variation. The slope of the long-term trend can be obtained by fitting these data to a function composed of an annual sine wave superimposed to a linear trend.…”

Section: Underground Measurements At Vincennesmentioning

confidence: 99%

“…Its roof is 18 m thick. Natural ventilation operates mainly through the access pit, with a diameter of about 4.6 m (Perrier et al, 2004). Temperatures are recorded, in the atmosphere, by Seabird  autonomous sensors.…”

Section: Underground Measurements At Vincennesmentioning

confidence: 99%

Long-term climate change and surface versus underground temperature measurements in Paris

et al. 2005

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Careful temperature measurements performed from 1783 to 1852 in underground galleries, 28 m below the Paris Observatory, are compared with current measurements performed in a limestone quarry, 20 m below ground surface, and with local and European surface temperature records. When averaged using a backward 11-year moving window, the surface temperature time series looks similar and exhibits the already well-known 1°C temperature increase over the last century. In addition, since about 1987, a steeper increase of about 0.07°C per year is noticed on all surface records. Underground temperatures, unaffected by surface fluctuations and averaging procedures, show a 0.9°C increase and thus confirm the trend indicated by the surface records. The averaged time series of the temperature in Paris and of the Wolf number, an indicator of sunspot activity, were reasonably well correlated till 1987 but deviated significantly from each other after that date. The long-term connection between surface temperature and solar cycles is further supported by a temporal analysis of the frequency content at 11 years and 5.5 years. Visual correlations between temperature and sunspot numbers, unconvincing when using recent records, appear more striking with underground data from 1783 to 1852. This analysis suggests that solar activity played an important role in temperature changes till the last century, but that different processes, possibly related to human-induced changes in the climate system, have been taking place lately with increasing intensity, especially since 1987.

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Radon-222 signatures of natural ventilation regimes in an underground quarry

Cited by 73 publications

References 30 publications

Reasons for large fluctuation of radon and CO<sub>2</sub> levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)

Reasons for large fluctuation of radon and CO<sub>2</sub> levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)

Dependence of radon levels in Postojna Cave on outside air temperature

Long-term climate change and surface versus underground temperature measurements in Paris

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Radon-222 signatures of natural ventilation regimes in an underground quarry

Cited by 73 publications

References 30 publications

Reasons for large fluctuation of radon and CO&lt;sub&gt;2&lt;/sub&gt; levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)

Reasons for large fluctuation of radon and CO&lt;sub&gt;2&lt;/sub&gt; levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)

Dependence of radon levels in Postojna Cave on outside air temperature

Long-term climate change and surface versus underground temperature measurements in Paris

Contact Info

Product

Resources

About

Reasons for large fluctuation of radon and CO<sub>2</sub> levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)

Reasons for large fluctuation of radon and CO<sub>2</sub> levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)