Effect of Moisture Content on Radon Emanation from Uranium Ore and Tailings

Strong, Kaye P.; Levins, D.M.

doi:10.1097/00004032-198201000-00003

Cited by 113 publications

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“…The details of this tendency were examined, paying particular attention to the emanation coefficient which influences the exhalation rate. The thoron exhalation rate was obtained by changing the emanation coefficient that was given by Strong and Levins 20) from À30% to +30% with an interval of 10%, and it was shown with the measured exhalation rate in Fig. 6(c).…”

Section: Comparison Of the Measured And Calculated Thoron Exhalation mentioning

confidence: 91%

“…Although the radon emanation coefficient for soil has been determined in many previous studies, 9,[19][20][21][22][23][24] only Strong and Levins 20) have presented continuous measurements of both radon emanation coefficient and moisture content. In the theoretical estimation, therefore, we calculated the radon exhalation rate with the data of Strong and Levins.…”

Section: Theoretical Calculation Of Radon and Thoron Exhalation Ratesmentioning

confidence: 99%

“…The emanation coefficient of soil was read from a graph concerning the relationship between the emanation coefficient and each measured moisture content shown by Strong and Levins. 20) As a result, the emanation coefficient varied widely, being in the range of 0.079-0.28. The thoron emanation coefficient for soil has been previously reported by Megumi and Mamuro.…”

Section: Theoretical Calculation Of Radon and Thoron Exhalation Ratesmentioning

confidence: 99%

“…We, therefore, substituted the emanation coefficient of radon for that of thoron. 18,20) Important parameters used in the trial calculation are shown in Table 1.…”

Section: Theoretical Calculation Of Radon and Thoron Exhalation Ratesmentioning

confidence: 99%

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Effect of Soil Moisture Content on Radon and Thoron Exhalation

Hosoda

Shimo

Sugino

et al. 2007

J. Nucl. Sci. Technol.

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ÃÃIn this study, the authors considered the effect of soil moisture in the emanation process of radon and thoron gases. Weathered granite soil was selected as the test soil and it was packed in a polypropylene container (275 Â 210 mm 2 and 100 mm in height), up to 50 mm in depth from the bottom. The container was covered with the exhalation rate measuring instrument adopting the accumulation method and -particles were counted at 30 s intervals for 30 min to estimate the exhalation rates. A sporadic increase in the radon and thoron exhalation rates was caused by the increase in the moisture content up to 8%. However, the exhalation rates showed a decreasing tendency with the increase in moisture content over 8%. Although the measured radon exhalation rate was about 25% of the calculated one, both measured and calculated radon exhalation rates had similar trends with an increase in the moisture content in the soil. The measured thoron exhalation rate agreed well with the calculated one. When the moisture content was in the range of 3.5-18%, it was considered that applying the correlation between the moisture content and the measured thoron exhalation rate is useful for estimating the thoron effective diffusion coefficient.

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Section: Comparison Of the Measured And Calculated Thoron Exhalation mentioning

confidence: 91%

Section: Theoretical Calculation Of Radon and Thoron Exhalation Ratesmentioning

confidence: 99%

Section: Theoretical Calculation Of Radon and Thoron Exhalation Ratesmentioning

confidence: 99%

“…We, therefore, substituted the emanation coefficient of radon for that of thoron. 18,20) Important parameters used in the trial calculation are shown in Table 1.…”

Section: Theoretical Calculation Of Radon and Thoron Exhalation Ratesmentioning

confidence: 99%

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Effect of Soil Moisture Content on Radon and Thoron Exhalation

Hosoda

Shimo

Sugino

et al. 2007

J. Nucl. Sci. Technol.

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“…It thus depends on the mineral assembly and grain sizes (Megumi and Mamuro, 1974;Somlai et al, 2008), radium distribution (Semkow and Parekh, 1990;Greeman and Rose, 1996), water content and water distribution (Menetrez et al, 1996;Adler and Perrier, 2009;Breitner et al, 2010). Water content is an important factor recognized long ago (Auxier et al, 1974;Strong and Levins, 1982), causing an increase of E of about a factor of 2 at low saturations, with a maximum at around 5 to 15 % volumetric saturation for rock and soil samples, and a subsequent smaller decrease at higher saturation (e.g., Markkanen and Arvela, 1992;Menetrez et al, 1996). While experimental measurements of the variation of EC Ra with water content still need to be refined, its physical basis is now reasonably well understood (Barillon et al, 2005;Adler and Perrier, 2009).…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous temperature sensitivity of effective radium concentration from various rock and soil samples

Girault

Perrier

2011

Nat. Hazards Earth Syst. Sci.

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Abstract. Temporal variations of radon concentration, or spatial variations around geothermal systems, are partly driven by the effect of temperature on the radon source term, the effective radium concentration (EC Ra ). EC Ra from 12 crushed rock and 12 soil samples from Nepal was measured in the laboratory using the radon accumulation method and Lucas scintillation flasks at three temperatures: 7, 22 and 37 • C. For each sample and at each temperature, 5 or 6 measurements were carried out, representing a total of 360 measurements, with an EC Ra average varying from 1.1 to 75 Bq kg −1 . While the effect is small, EC Ra was observed to increase with temperature in a significant and sufficiently reproducible manner. The increase was approximately linear with a slope (temperature sensitivity, TS) expressed in % • C −1 . We observed a large heterogeneity of TS with average values (range min-max) of 0.79 ± 0.05 (0.16-2.0) % • C −1 and 0.61 ± 0.05 (0.10-2.0) % • C −1 , for rock and soil samples, respectively. While this range overlaps with the results of previous studies, our values of TS tend to be smaller. The observed heterogeneity implies that the TS, rather poorly understood, needs to be assessed by dedicated experiments in every case where it is of consequence for the interpretation.

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Radon: Radionuclides

Tracy¹

2005

Encyclopedia of Inorganic Chemistry

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Radon is a naturally occurring radioactive gas formed by the decay of uranium and thorium in the Earth's crust. At atomic number 86, it is the heaviest member of the noble or inert gas family, which also includes helium, neon, argon, krypton, and xenon. Unlike the other members of the family, radon has no stable isotopes. Of the 34 known radioactive isotopes of radon, only three are supported by the decay of primordial radionuclides, and only two occur with any significant abundance in nature. The three isotopes, along with their half‐lives, are 222 Rn (3.8235 days), 220 Rn (55.6 s), and 219 Rn (3.96 s). Both 222 Rn and 220 Rn decay by the emission of α‐particles and give rise to a number of short‐lived progeny. 222 Rn and 220 Rn are the only ones regarded as having any health impacts and this is due to their short‐lived progeny— 218 Po, 214 Pb, 214 Bi, and 214 Po from 222 Rn; 216 Po, 212 Pb, 212 Bi, 212 Po, and 208 Tl from 220 Rn. Being a gas, radon diffuses readily into the atmosphere and may build up to hazardous concentrations in confined spaces in homes and underground mines. Radon is the largest single contributor to natural background radiation exposure worldwide. Radon is now recognized as the second leading cause of lung cancer, following tobacco smoking, and is responsible for up to 20 000 deaths per year in the United States and 1900 deaths per year in Canada. Many countries have now established programs to reduce radon exposures to the population.

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Effect of Moisture Content on Radon Emanation from Uranium Ore and Tailings

Cited by 113 publications

References 0 publications

Effect of Soil Moisture Content on Radon and Thoron Exhalation

Effect of Soil Moisture Content on Radon and Thoron Exhalation

Heterogeneous temperature sensitivity of effective radium concentration from various rock and soil samples

Radon: Radionuclides

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