scholarly journals Long-Term Measurements of Radon and Thoron Exhalation Rates from the Ground Using the Vertical Distributions of Their Activity Concentrations

2021 ◽  
Vol 18 (4) ◽  
pp. 1489
Author(s):  
Oumar Bobbo Modibo ◽  
Yuki Tamakuma ◽  
Takahito Suzuki ◽  
Ryohei Yamada ◽  
Weihai Zhuo ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Long Term Results ◽  
Exhalation Rate ◽  
Radon Exhalation ◽  
Accumulation Chamber ◽  
Activity Concentrations ◽  
Vertical Distributions ◽  
Radon Exhalation Rates ◽  
Good Agreement

A long-term measurement technique of radon exhalation rate was previously developed using a passive type radon and thoron discriminative monitor and a ventilated type accumulation chamber. In the present study, this technique was applied to evaluate the thoron exhalation rate as well, and long-term measurements of radon and thoron exhalation rates were conducted for four years in Gifu Prefecture. The ventilated type accumulation chamber (0.8 × 0.8 × 1.0 m3) with an open bottom was embedded 15 cm into the ground. The vertical distributions of radon and thoron activity concentrations from the ground were obtained using passive type radon-thoron discriminative monitors (RADUETs). The RADUETs were placed at 1, 3, 10, 30, and 80 cm above the ground inside the accumulation chamber. The measurements were conducted from autumn 2014 to autumn 2018. These long-term results were found to be in good agreement with the values obtained by another methodology. The radon exhalation rates from the ground showed a clearly seasonal variation. Similar to findings of previous studies, radon exhalation rates from summer to autumn were relatively higher than those from winter to spring. In contrast, thoron exhalation rates were not found to show seasonal variation.

Influence of the accumulation chamber insertion depth to measure surface radon exhalation rates

2021 ◽  
Author(s):  
Isidoro Gutiérrez Álvarez ◽  
José Luis Guerrero ◽  
José Enrique Martín ◽  
José Antonio Adame ◽  
Juan Pedro Bolívar
Keyword(s):  
Field Experiments ◽  
Lateral Diffusion ◽  
External Effects ◽  
Insertion Depth ◽  
Radon Exhalation ◽  
Accumulation Chamber ◽  
Diffusion Effects ◽  
Radon Exhalation Rates ◽  
The City ◽  
Effective Decay

<p>A common method to measure radon exhalation rates relies on the accumulation chamber technique. Usually, this approach only considers one-dimensional gas transport within the soil that neglects lateral diffusion. However, this lateral transport could reduce the reliability of the method. In this work, several cylindrical- shaped accumulation chambers were built with different heights to test if the insertion depth of the chamber into the soil improves the reliability of the method and, in that case, if it could limit the radon lateral diffusion effects. To check this hypothesis in laboratory, two reference exhalation boxes were manufactured using phospho- gypsum from a repository located nearby the city of Huelva, in the southwest of Spain. Laboratory experiments showed that insertion depth had a deep impact in reducing the effective decay constant of the system, extending the interval where the linear fitting can be applied, and consistently obtaining reliable exhalation measurements once a minimum insertion depth is employed. Field experiments carried out in the phosphogypsum repository showed that increasing the insertion depth could reduce the influence of external effects, increasing the re- peatability of the method. These experiments provided a method to obtain consistent radon exhalation mea- surements over the phosphogypsum repository.</p>

scholarly journals Influence of the accumulation chamber insertion depth to measure surface radon exhalation rates

2020 ◽  
Vol 393 ◽  
pp. 122344
Author(s):  
I. Gutiérrez-Álvarez ◽  
J.L. Guerrero ◽  
J.E. Martín ◽  
J.A. Adame ◽  
J.P. Bolívar
Keyword(s):  
Insertion Depth ◽  
Radon Exhalation ◽  
Accumulation Chamber ◽  
Radon Exhalation Rates

scholarly journals The activity concentrations of 222Rn in some groundwater wells, Najran City, Saudi Arabia

2017 ◽  
Vol 32 (2) ◽  
pp. 166-173 ◽  
Author(s):  
Tayseer Al-Naggar ◽  
Ayman Abdalla
Keyword(s):  
Saudi Arabia ◽  
Radon Exhalation Rate ◽  
Exhalation Rate ◽  
Radon Exhalation ◽  
Passive Measurement ◽  
Activity Concentrations ◽  
Effective Doses ◽  
Linear Correlations ◽  
Groundwater Wells ◽  
Radon Concentrations

In this work, the radon exhalation rate, effective radium content and radiation doses from some groundwater wells in Najran City, Saudi Arabia, were addressed and discussed in detail. This survey of radon concentrations in the groundwater was carried out using the passive measurement technique, where the radon gas passively diffuses into the detector. The obtained results revealed that the radon exhalation rate in terms of area and mass exhibits linear correlations with effective radium in groundwater (correlation coefficient R2 = 1). Also, the majority of radon concentrations are within the UNSCEAR 1993 permitted level and the average annual effective doses obtained for radium and radon are 180 ?Sv and 860 ?Sv, respectively.

Measurements of radon exhalation from a South African gold mine tailings using sealed tube method

2021 ◽  
Author(s):  
F.S. Komati ◽  
R. Strydom ◽  
O.M. Ntwaeaborwa
Keyword(s):  
South African ◽  
Mine Tailings ◽  
Mining Area ◽  
Mean Value ◽  
Gold Mine ◽  
Exhalation Rate ◽  
Radon Exhalation ◽  
Radon Gas ◽  
Gold Mine Tailings ◽  
Radon Exhalation Rates

To date, approximately 6000 tons of uranium has been disposed of onto tailings dams per year by gold mining activities in South Africa. These uranium bearing tailings dumps contain significant amounts of radium and are therefore possible sources of substantial amounts of radon gas. Due to the large sizes of these dams, measurements of the radon exhalation for the whole dam using established and conventional methods become time consuming and labour intensive. In this study, radon exhalation rates from a gold mine tailings dam around mining area of Odendalsrus were measured using passive “sealed tube” method and CR-39 gas etched track monitors known as Radon Gas Monitors (RGMs). Twenty samples were collected at the depths ranging from 90 cm to 1 m from the tailings for exhalation rate measurements. Radon exhalation rates from these samples were found to vary from 0.0410 ± 0.0042 Bq/m2 · s to 0.440 ± 0.045 Bq/m2 · s with a mean value of 0.102 ± 0.021 Bq/m2 · s and a standard deviation of 0.087 Bq/m2 · s. The results of these measurements show very high radon exhalation rate and radium content from one particular sample which requires further investigations.

Experimental study of the effect of seepage on radon exhalation in circular tubular porous emanation media

2019 ◽  
Vol 29 (5) ◽  
pp. 701-710
Author(s):  
Yongjun Ye ◽  
Wenhao Wu ◽  
Chunhua Huang ◽  
Kimberlee J. Kearfott
Keyword(s):  
Pressure Side ◽  
Radon Exhalation Rate ◽  
Pressure Gradients ◽  
Exhalation Rate ◽  
Seepage Velocity ◽  
Radon Exhalation ◽  
Maximum Value ◽  
Diffusion Migration ◽  
Velocity Pressure ◽  
Good Agreement

Radium, which is naturally present in many rocks, decays to the radioactive gas radon, which is then exhaled from the surface of underground tunnels and other underground buildings and is a major source of human exposure to radioactivity. A mathematical model for the migration of radon from a circular tubular emanation medium was established based on the seepage–diffusion migration theory for radon in porous emanation media, such as artificial retaining walls and the surrounding rocks in these locations. An analytical solution for the distribution of radon concentrations and the calculation formula for the radon exhalation rate under steady-state conditions were then obtained. An experimental device was designed to determine the radon exhalation rate under different pressure gradients. The theoretical calculation values for the radon exhalation rate and the total amount of radon exhalation are in good agreement with the experimental results. The radon exhalation rate at the low-pressure side increases with an increase in seepage velocity (pressure difference), while the radon exhalation rate at the high-pressure side is on the contrary. The total amount of radon exhalation increased over time with an increase in the seepage velocity and tended towards a maximum value.

scholarly journals Measurement of Radon Concentration Using SSNTD in Bartella Region

2019 ◽  
Vol 29 (4) ◽  
pp. 110 ◽  
Author(s):  
Malik Hussain Kheder
Keyword(s):  
Radon Concentration ◽  
Mean Value ◽  
Exhalation Rate ◽  
High Concentration ◽  
Radon Exposure ◽  
Radon Exhalation ◽  
Radon Activity ◽  
Activity Concentrations ◽  
The Earth ◽  
Can Technique

The alpha-radioactive inert gas Radon exhalation is associated with presence of Radium and its ultimate precursor uranium in the earth crust. Uranium decay deposits radon in soil, which is harmful on human and environment. The exposure of population to high concentration of alpha radioactivity mainly of Radon for a long period leads to lung cancer. The radon activity concentrations, radium contents, radon exhalation rates in twenty one soil samples collected from Bartella region, were measured using the sealed-can technique based on the CR-39 SSNTDs. In the present paper the estimated values for radon activity concentration in air space are in the range 323.2-2424 Bq/m3 with mean value of 1212.7 Bq/m3, the radon concentration in soil sample are 31.66-237.46 KBq/m3 with mean value of 118.83 KBq/m3, the radium contents were found vary between 1.36-10.24 Bq/Kg with mean value 5.11 Bq/Kg, the radon mass exhalation rate vary between 10.34-77.56 mBq/Kg/hr with mean 38.81 mBq/Kg/hr, the radon surface exhalation rate are between 234.2-1756.4 mBq/m2/hr with mean value of 878.6 mBq/m2/hr. All values of the samples under the test are below of permissible values 370 Bq/Kg of radium content and 57600 mBq/m2/hr radon exhalation, recommended by Organization for Economic Cooperation and Development (OECD). Hence the area under investigation is safe as for as health hazards of radium and safe in radiological risks due to radon exposure from the soil.

scholarly journals Radon exhalation rates of some granites used in Serbia

2015 ◽  
Vol 30 (2) ◽  
pp. 145-148
Author(s):  
Mladen Nikolic ◽  
Rodoljub Simovic
Keyword(s):  
Measurement Technique ◽  
Back Diffusion ◽  
Radon Exhalation Rate ◽  
Exhalation Rate ◽  
Closed Chamber ◽  
Radon Measurement ◽  
Radon Exhalation ◽  
Radium Content ◽  
Radon Exhalation Rates ◽  
Closed Chamber Method

In order to address concern about radon exhalation in building material, radon exhalation rate was determined for different granites available on Serbian market. Radon exhalation rate, along with mass exhalation rate and effective radium content were determined by closed chamber method and active continuous radon measurement technique. For this research, special chambers were made and tested for back diffusion and leakage, and the radon concentrations measured were included in the calculation of radon exhalation. The radon exhalation rate ranged from 0.161 Bq/m2h to 0.576 Bq/m2h, the mass exhalation rate from 0.167 Bq/kgh to 0.678 Bq/kgh, while the effective radium content was found to be from 12.37 Bq/kg to 50.23 Bq/kg. The results indicate that the granites used in Serbia have a low level of radon exhalation.

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