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Xia M, Ye Y, Zhou N. Novel approaches for accurately measuring radon exhalation rate and mechanism interpreted by numerical simulation. JOURNAL OF HAZARDOUS MATERIALS 2024; 468:133865. [PMID: 38412801 DOI: 10.1016/j.jhazmat.2024.133865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 02/29/2024]
Abstract
Measurements of radon exhalation rate using traditional methods can be affected by back-diffusion or differential pressure in the accumulation chamber, resulting in deviations between the measured and the true values. To obtain an accurate radon exhalation rate for evaluation of radon-risk regions, two novel approaches of measurements based on traditional methods were proposed. Repeated experiments were implemented on a self-designed stainless cylindrical vessel filled with uranium tailings sand. The measured radon exhalation rates on average were 0.51 ± 0.02 and 0.52 ± 0.02 Bq m-2 s-1 for the two proposed methods, with 0.02% and 0.04%, respectively, deviations from the theoretical value. In addition, numerical techniques were employed to interpret the defects of traditional methods and mechanisms of proposed approaches to measure accurate values. Two novel approaches have significantly reduced the impact of back diffusion and differential pressure inside the chamber and consumed less time.
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Affiliation(s)
- Ming Xia
- School of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, China
| | - Yongjun Ye
- School of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, China; Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China.
| | - Ning Zhou
- School of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, China
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Fuhrmann M, Benson CH, Likos WJ, Stefani N, Michaud A, Waugh WJ, Williams MM. Radon fluxes at four uranium mill tailings disposal sites after about 20 years of service. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 237:106719. [PMID: 34454248 DOI: 10.1016/j.jenvrad.2021.106719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 06/28/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
To evaluate the properties of earthen covers over uranium mill tailings disposal cells after about 20 years of service, we measured Rn-222 fluxes and radon barrier properties at the Falls City, TX, Bluewater, NM, Shirley Basin South, WY, and Lakeview, OR disposal sites in western USA. A total of 115 in-service Rn fluxes were obtained at 26 test pit locations from the top surface of the exposed Rn barrier (i.e., after protective layers were removed by excavation) and 24 measurements were obtained from the surface of the underlying waste after excavation through the Rn barrier layer. Rn-222 concentrations were determined in accumulation chambers using a continuously monitoring electronic radon monitor (ERM) equipped with a solid-state alpha particle detector. Effects of surface features on Rn flux including vegetation, seasonal ponding, and animal burrowing were quantified. Comparison of measured fluxes with values that were measured shortly after the Rn barriers were completed (as-built) show that most measurements fell within the range of the as-built fluxes, generally at very low fluxes. At two sites fluxes were measured that were greater than the highest as-built flux. High fluxes are typically caused by a combination of enhanced moisture removal and preferential pathways for Rn transport, often caused by deep-rooted plants. Such localized features result in a spatially heterogeneous distribution of fluxes that can vary substantially over only a meter or two.
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Affiliation(s)
- Mark Fuhrmann
- Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Rockville, MD, 20852, USA
| | - Craig H Benson
- Consortium for Risk Evaluation with Stakeholder Participation (CRESP) and Geological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - William J Likos
- Geological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA.
| | - Nicolas Stefani
- Geological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - Alex Michaud
- Geological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
| | - W Joseph Waugh
- RSI Entech, 2597 Legacy Way, Grand Junction, CO, 81503, USA
| | - Morgan M Williams
- Department of Geography - ESDL, University of California, Berkeley, 505 McCone Hall #4740, Berkeley, CA, 94720-4740, USA
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Szajerski P, Zimny A. Numerical analysis and modeling of two-loop experimental setup for measurements of radon diffusion rate through building and insulation materials. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 256:113393. [PMID: 31733950 DOI: 10.1016/j.envpol.2019.113393] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/11/2019] [Accepted: 10/12/2019] [Indexed: 06/10/2023]
Abstract
Radon is a natural radioactive gas present in the environment, which is considered as the second most important lung cancer cause worldwide. Currently, radon gas is under focus and was classified as contaminant of emerging concern, which is responsible for serious biological/health effects in human. In presented work we propose the numerical model and analysis method for radon diffusion rate measurements and radon transport parameters determination. The experimental setup for radon diffusion was built in a classical, two chamber configuration, in which the radon source and outlet reservoirs are separated by the sample being tested. The main difference with previously known systems is utilization of only one radon detector, what was achieved by a careful characterization of the Rn-222 source and development of a numerical model, which allows for exact determination of radon transport parameters by fitting simulated radon concentration profile in the outlet reservoir to experimental data. For verification of the developed system, several insulation materials commonly used in building industry and civil engineering, as well as, common building materials (gypsum, hardened cement paste, concrete) were tested for radon diffusion rate through these barriers. The results of radon transmittance, permeability and diffusion coefficients for investigated materials are in compliance with values known previously from the literature. The analysis method is fast and efficient, and requires measurement period varying from a dozen or so hours up to 2-3 days depending on material properties. The described method is entirely based on a numerical analysis of the proposed differential equation model using freely available SCILAB software and experimental data obtained during sample measurements.
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Affiliation(s)
- Piotr Szajerski
- Institute of Applied Radiation Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590 Lodz, Poland.
| | - Arkadiusz Zimny
- Institute of Applied Radiation Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590 Lodz, Poland.
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Li X, Xu X, Li W, Wang F, Hai C. Preliminary study on the variation of radon-222 inside greenhouse of Shouguang county, China. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 153:120-125. [PMID: 26771243 DOI: 10.1016/j.jenvrad.2015.12.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/18/2015] [Accepted: 12/28/2015] [Indexed: 06/05/2023]
Abstract
Studies on radon have become the focus of indoor radiation. In this study, we chose greenhouse to be the study field, the research aims to: (1) explore the diurnal variation of radon concentration inside greenhouse in Shouguang county, China; (2) pre-analyze the relationship between radon concentration, temperature and relative humidity, and shed light on the radon behavior characteristic inside greenhouse; (3) verify the feasibility of calculating radon radiation dose by using short-period detected radon concentrations in typical months in Shouguang county. The following conclusions were drawn. Firstly, the average radon levels in typical months in Shouguang county are all much higher than that in ordinary dwellings in China, diurnal and seasonal variations in radon levels are observed inside greenhouse. Secondly, temperature and relative humidity may play a role indirectly through affecting soil moisture and other factors. The mechanism need to be further studied. Thirdly, radon concentrations detected in typical months are still useful in preliminary estimation of radon radiation dose for vegetable-plant farmers in Shouguang county.
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Affiliation(s)
- Xiaohong Li
- Department of Toxicology, School of Military Preventive Medicine, The Fourth Military Medical University, Xi'an 710032, Shanxi, China; College of Public Health and Management, Weifang Medical University, Weifang 261053, Shandong, China
| | - Xianqin Xu
- Affiliated Hospital of Weifang Medical University, Yuhe Road, 261031 Weifang, Shandong Province, China
| | - Wanwei Li
- College of Public Health and Management, Weifang Medical University, Weifang 261053, Shandong, China.
| | - Fei Wang
- College of Public Health and Management, Weifang Medical University, Weifang 261053, Shandong, China
| | - Chunxu Hai
- Department of Toxicology, School of Military Preventive Medicine, The Fourth Military Medical University, Xi'an 710032, Shanxi, China.
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Abbasi A, Mirekhtiary F. Comparison of active and passive methods for radon exhalation from a high-exposure building material. RADIATION PROTECTION DOSIMETRY 2013; 157:570-574. [PMID: 23798709 DOI: 10.1093/rpd/nct163] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The radon exhalation rates and radon concentrations in granite stones used in Iran were measured by means of a high-resolution high purity Germanium gamma-spectroscopy system (passive method) and an AlphaGUARD model PQ 2000 (active method). For standard rooms (4.0 × 5.0 m area × 2.8 height) where ground and walls have been covered by granite stones, the radon concentration and the radon exhalation rate by two methods were calculated. The activity concentrations of (226)Ra in the selected granite samples ranged from 3.8 to 94.2 Bq kg(-1). The radon exhalation rate from the calculation of the (226)Ra activity concentration was obtained. The radon exhalation rates were 1.31-7.86 Bq m(-2)h(-1). The direction measurements using an AlphaGUARD were from 218 to 1306 Bq m(-3) with a mean of 625 Bq m(-3). Also, the exhalation rates measured by the passive and active methods were compared and the results of this study were the same, with the active method being 22 % higher than the passive method.
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Affiliation(s)
- A Abbasi
- Department of Physics, Eastern Mediterranean University, Famagusta, North Cyprus, Mersin10, Turkey
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Allen JG, Zwack LM, MacIntosh DL, Minegishi T, Stewart JH, McCarthy JF. Predicted indoor radon concentrations from a Monte Carlo simulation of 1,000,000 granite countertop purchases. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2013; 33:151-162. [PMID: 23295242 DOI: 10.1088/0952-4746/33/1/151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Previous research examining radon exposure from granite countertops relied on using a limited number of exposure scenarios. We expanded upon this analysis and determined the probability that installing a granite countertop in a residential home would lead to a meaningful radon exposure by performing a Monte Carlo simulation to obtain a distribution of potential indoor radon concentrations attributable to granite. The Monte Carlo analysis included estimates of the probability that a particular type of granite would be purchased, the radon flux associated with that type, the size of the countertop purchased, the volume of the home where it would be installed and the air exchange rate of that home. One million countertop purchases were simulated and 99.99% of the resulting radon concentrations were lower than the average outdoor radon concentrations in the US (14.8 Bq m(-3); 0.4 pCi l(-1)). The median predicted indoor concentration from granite countertops was 0.06 Bq m(-3) (1.59 × 10(-3) pCi l(-1)), which is over 2000 times lower than the US Environmental Protection Agency's action level for indoor radon (148 Bq m(-3); 4 pCi l(-1)). The results show that there is a low probability of a granite countertop causing elevated levels of radon in a home.
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Affiliation(s)
- J G Allen
- Environmental Health and Engineering, Inc., 117 Fourth Avenue, Needham, MA 02494, USA.
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Zhang L, Lei X, Guo Q, Wang S, Ma X, Shi Z. Accurate measurement of the radon exhalation rate of building materials using the closed chamber method. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2012; 32:315-323. [PMID: 22809839 DOI: 10.1088/0952-4746/32/3/315] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The construction department of the Chinese government is now discussing the possibility of reducing indoor radon exposure through controlling the radon exhalation rate of building materials. However, which quantity is suitable for control and how to specify and measure this quantity are still not clear. A comparison of a theoretical model and measurement process of radon exhalation between the surface of soil and building materials was carried out. As a result, the so-called intrinsic exhalation rate is thought to be a suitable quantity for control. Through theoretical analysis and experimental comparisons of different pre-treatment methods, it was indicated that the closed chamber method could be used to measure the intrinsic exhalation rate of building materials. Measurement results show that the average intrinsic radon exhalation rate of building materials commonly used in Beijing is 4.891 mBq m(-2) s(-1), with a range of 0.323-21.250 mBq m(-2) s(-1), and the average diffusion length is 16.448 cm, with a range of 2.371-41.960 cm.
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Affiliation(s)
- Lei Zhang
- Solid Dosimetric Detector and Method Laboratory, Beijing 102205, People's Republic of China
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Allen JG, Minegishi T, Myatt TA, Stewart JH, McCarthy JF, Macintosh DL. Assessing exposure to granite countertops--Part 2: Radon. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2010; 20:263-272. [PMID: 19707250 DOI: 10.1038/jes.2009.43] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 06/20/2009] [Accepted: 07/13/2009] [Indexed: 05/28/2023]
Abstract
Radon gas ((222)Rn) is a natural constituent of the environment and a risk factor for lung cancer that we are exposed to as a result of radioactive decay of radium ((226)Ra) in stone and soil. Granite countertops, in particular, have received recent media attention regarding their potential to emit radon. Radon flux was measured on 39 full slabs of granite from 27 different varieties to evaluate the potential for exposure and examine determinants of radon flux. Flux was measured at up to six pre-selected locations on each slab and also at areas identified as potentially enriched after a full-slab scan using a Geiger-Muller detector. Predicted indoor radon concentrations were estimated from the measured radon flux using the CONTAM indoor air quality model. Whole-slab average emissions ranged from less than limit of detection to 79.4 Bq/m(2)/h (median 3.9 Bq/m(2)/h), similar to the range reported in the literature for convenience samples of small granite pieces. Modeled indoor radon concentrations were less than the average outdoor radon concentration (14.8 Bq/m(3); 0.4 pCi/l) and average indoor radon concentrations (48 Bq/m(3); 1.3 pCi/l) found in the United States. Significant within-slab variability was observed for stones on the higher end of whole slab radon emissions, underscoring the limitations of drawing conclusions from discrete samples.
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Affiliation(s)
- Joseph G Allen
- Environmental Health & Engineering, Needham, MA 02494-2725, USA.
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Chen J, Rahman NM, Abu Atiya I. Radon exhalation from building materials for decorative use. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2010; 101:317-22. [PMID: 20167403 DOI: 10.1016/j.jenvrad.2010.01.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 01/15/2010] [Accepted: 01/21/2010] [Indexed: 05/10/2023]
Abstract
Long-term exposure to radon increases the risk of developing lung cancer. There is considerable public concern about radon exhalation from building materials and the contribution to indoor radon levels. To address this concern, radon exhalation rates were determined for 53 different samples of drywall, tile and granite available on the Canadian market for interior home decoration. The radon exhalation rates ranged from non-detectable to 312 Bq m(-2) d(-1). Slate tiles and granite slabs had relatively higher radon exhalation rates than other decorative materials, such as ceramic or porcelain tiles. The average radon exhalation rates were 30 Bq m(-2) d(-1) for slate tiles and 42 Bq m(-2) d(-1) for granite slabs of various types and origins. Analysis showed that even if an entire floor was covered with a material having a radon exhalation rate of 300 Bq m(-2) d(-1), it would contribute only 18 Bq m(-3) to a tightly sealed house with an air exchange rate of 0.3 per hour. Generally speaking, building materials used in home decoration make no significant contribution to indoor radon for a house with adequate air exchange.
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Affiliation(s)
- Jing Chen
- Radiation Protection Bureau, Health Canada, 775 Brookfield Road, Ottawa K1A 1C1, Canada.
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Kotrappa P, Stieff F. Radon exhalation rates from building materials using electret ion chamber radon monitors in accumulators. HEALTH PHYSICS 2009; 97:163-166. [PMID: 19590276 DOI: 10.1097/hp.0b013e3181a9ab15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
An electret ion chamber (EIC) radon monitor in a sealed accumulator measures the integrated average radon concentration at the end of the accumulation duration. Theoretical equations have been derived to relate such radon concentrations (Bq m(-3) ) to the radon emanation rate (Bq d(-1)) from building materials enclosed in the accumulator. As an illustration, a 4-L sealable glass jar has been used as an accumulator to calculate the radon emanation rate from different granite samples. The radon emanation rate was converted into radon flux (Bq mm(-2) d(-1)) by dividing the emanation rate by surface area of the sample. Fluxes measured on typical, commercially available granites ranged from 20-30 Bq m(-2) d(-1). These results are similar to the results reported in the literature. The lower limit of detection for a 2-d measurement works out to be 7 Bq m(-2) d(-1). Equations derived can also be used for other sealable accumulators and other integrating detectors, such as alpha track detectors.
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HASSAN NM, HOSODA M, ISHIKAWA T, SORIMACHI A, SAHOO SK, TOKONAMI S, FUKUSHI M. Radon Migration Process and Its Influence Factors; Review. ACTA ACUST UNITED AC 2009. [DOI: 10.5453/jhps.44.218] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Nabil M. HASSAN
- School of Radiological Sciences, Tokyo Metropolitan University
- Research Centre for Radiation Protection, National Institute of Radiological Sciences
- Department of Physics, Faculty of Science, University of Zagazig
| | - Masahiro HOSODA
- Research Centre for Radiation Protection, National Institute of Radiological Sciences
| | - Tetsuo ISHIKAWA
- Research Centre for Radiation Protection, National Institute of Radiological Sciences
| | - Atsuyuki SORIMACHI
- Research Centre for Radiation Protection, National Institute of Radiological Sciences
| | - Sarata K. SAHOO
- Research Centre for Radiation Protection, National Institute of Radiological Sciences
| | - Shinji TOKONAMI
- Research Centre for Radiation Protection, National Institute of Radiological Sciences
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Ruano-Ravina A, Castro-Bernárdez M, Sande-Meijide M, Vargas A, Barros-Dios JM. Short- versus long-term radon detectors: a comparative study in Galicia, NW Spain. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2008; 99:1121-1126. [PMID: 18313815 DOI: 10.1016/j.jenvrad.2008.01.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 01/02/2008] [Accepted: 01/14/2008] [Indexed: 05/26/2023]
Abstract
As reported in previous studies, Galicia (NW Spain) is an area of high radon concentrations. This study was sought to analyze the correlation between short-term (activated carbon) and long-term (alpha particle track) detectors in this geographic area, and ascertain whether there were differences in their readings that might be influenced by other variables. A comparison study, as part of a case-control study was designed in which two detectors, one of each type, were placed in the selected homes. A total of 391 homes yielded readings with both detectors. The results indicated that there was a relatively good correlation between both types of monitors (correlation coefficient 0.608; p<0.001). The highest correlations between both detectors were observed for unventilated homes, coastal sites, and the oldest buildings. Short-term and long-term detectors do not show a similar performance in all settings or situations. It is advisable to use long-term detectors whenever possible.
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Affiliation(s)
- A Ruano-Ravina
- Department of Preventive Medicine and Public Health, School of Medicine, University of Santiago de Compostela, San Francisco, 15782 Santiago de Compostela, Spain.
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Fournier F, Groetz JE, Jacob F, Crolet JM, Lettner H. Simulation of Radon Transport through Building Materials: Influence of the Water Content on Radon Exhalation Rate. Transp Porous Media 2005. [DOI: 10.1007/s11242-004-1489-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Jang M, Kang CS, Hyun Moon J. Estimation of 222Rn release from the phosphogypsum board used in housing panels. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2005; 80:153-160. [PMID: 15701380 DOI: 10.1016/j.jenvrad.2004.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2004] [Revised: 08/01/2004] [Accepted: 08/10/2004] [Indexed: 05/24/2023]
Abstract
Phosphogypsum board is a popular construction material used for housing panels in Korea. Phosphogypsum often contains (226)Ra which decays into (222)Rn through an alpha transformation. (222)Rn emanated from the (226)Ra-bearing phosphogypsum board has drawn the public concern due to its potential radiological impacts to indoor occupants. The emanation rate of (222)Rn from the board is estimated in this paper. A mathematical model of the emanation rate of (222)Rn from the board is presented and validated through a series of experiments. The back diffusion effect due to accumulation of (222)Rn-laden air was incorporated in the model and found to have a strong impact on the (222)Rn emanation characteristics.
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Affiliation(s)
- Mee Jang
- Department of Nuclear Engineering, Seoul National University, 56-1, Shillim, Gwanak, Seoul 151-742, Republic of Korea.
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