Radium activity and radon exhalation rates from phosphate ores using CR-39 on-line with an electronic radon gas analyzer “Alpha GUARD”

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.

Download Full-text

Study on the Reduction of Radon Exhalation Rates of Concrete with Different Activated Carbon

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.726.558 ◽

2017 ◽

Vol 726 ◽

pp. 558-563

Author(s):

Yong Gui Zhang ◽

Yang Wang ◽

Chun Yong Yang ◽

Gui Qiang Li ◽

Hao Chun Yan

Keyword(s):

Activated Carbon ◽

Pore Distribution ◽

Coconut Shell ◽

Radon Exhalation ◽

Adsorption Mechanisms ◽

Radon Gas ◽

Radon Exhalation Rates

Four different material of activated carbon, i.e., coconut shell, fruit shell, wood and coal, were used to be mixed with concrete, the radon exhalation rates of concrete then was measured. At the same time, the pore distribution of activated carbon and some performances of concrete were tested. The results show that coconut shell carbon has the best effect for reduction radon exhalation rates of concrete, fruit shell carbon comes second. The adsorption mechanisms of activated carbon towards the radon gas in the solid and in the air are similar. Activated carbon have less effect on the strength of concrete, however, they have greater influence on the constructability and durability.

Download Full-text

Apparatus for purifying pre-treatment in on-line coal gas analyzer with desulfurization

Fuel and Energy Abstracts ◽

10.1016/s0140-6701(02)80276-4 ◽

2002 ◽

Vol 43 (1) ◽

pp. 27

Keyword(s):

Gas Analyzer ◽

Coal Gas ◽

On Line ◽

Pre Treatment

Download Full-text

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

10.5194/egusphere-egu21-4222 ◽

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>

Download Full-text