1
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Adelikhah M, Imani M, Kovács T. Development of a thoron calibration chamber based on computational fluid dynamics simulation and validation with measurements. Sci Rep 2023; 13:13611. [PMID: 37604958 PMCID: PMC10442380 DOI: 10.1038/s41598-023-40776-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 08/16/2023] [Indexed: 08/23/2023] Open
Abstract
Recently, interest in measuring the concentration of 220Rn in air has increased greatly following the development of standards and the calibration of monitoring instruments. In this study, a 220Rn calibration chamber was designed and developed at the Institute of Radiochemistry and Radioecology (RRI) based on the computational fluid dynamics (CFD) method implemented in ANSYS Fluent 2020 R1 code at the University of Pannonia in Hungary. The behavior of 220Rn and its spatial distribution inside the 220Rn calibration chamber at RRI were investigated at different flow rates. The 220Rn concentration was close to homogeneous under higher flow regimes due to thorough mixing of the gas inside the chamber. Predictions based on CFD simulations were compared with experimentally measured transmission factors (Cout/Cin). The spatial distribution of 220Rn was dependent on the flow rate and the positions of the inlet and outlet. Our results clearly demonstrate the suitability of the 220Rn calibration chamber at RRI for calibrating monitoring instruments. Furthermore, the CFD-based predictions were in good agreement with the results obtained at higher flow rates using experimental and analytical models according to the relative deviation, with a maximum of approximately 9%.
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Affiliation(s)
- Mohammademad Adelikhah
- Institute of Radiochemistry and Radioecology; Research Centre for Biochemical, Environmental and Chemical Engineering, University of Pannonia, Veszprém, 8200, Hungary
| | - Morteza Imani
- Engineering Department, Shahid Beheshti University, Tehran, Iran
| | - Tibor Kovács
- Institute of Radiochemistry and Radioecology; Research Centre for Biochemical, Environmental and Chemical Engineering, University of Pannonia, Veszprém, 8200, Hungary.
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2
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Voltattorni N, Gasparini A, Galli G. The Analysis of 222Rn and 220Rn Natural Radioactivity for Local Hazard Estimation: The Case Study of Cerveteri (Central Italy). INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:6420. [PMID: 37510652 PMCID: PMC10378882 DOI: 10.3390/ijerph20146420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/18/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023]
Abstract
Radon (222Rn) is the second most common cause of lung cancer after smoking. As radon poses a significant risk to human health, radon-affected areas should be identified to ensure people's awareness of risk and remediation. The primary goal of this research was to investigate the local natural radioactivity (in soils, groundwater, and indoors) because of the presence of tuff outcrops (from middle-lower Pleistocene volcanic activity) that naturally produce radioactive gas radon at Cerveteri (Rome, Central Italy). The results of the radon survey highlighted moderate (>16,000 Bq/m3) but localized anomalies in soils in correspondence with a funerary site pertaining to the Etruscan Necropolis of Cerveteri, which extends over a volcanic rock plateau. Indoor radon measurements were performed at several tuff-made dwellings, and the results showed medium-low (<200 Bq/m3) values of indoor radon except for some cases exceeding the reference level (>300 Bq/m3) recommended by the 2013/59 Euratom Directive. Although no clinical data exist regarding the health effects of thoron (220Rn) on humans, the study of 220Rn average activity concentration in the soil gas survey reveals new insights for the interpretation of radon sources that can affect dwellings, even taking into account the considerable difference in the half-lives of 222Rn and 220Rn.
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Affiliation(s)
- Nunzia Voltattorni
- Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome, Italy
| | - Andrea Gasparini
- Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome, Italy
| | - Gianfranco Galli
- Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome, Italy
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3
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Adelikhah M, Imani M, Kovács T. Measurements and computational fluid dynamics investigation of the indoor radon distribution in a typical naturally ventilated room. Sci Rep 2023; 13:2064. [PMID: 36739299 PMCID: PMC9899222 DOI: 10.1038/s41598-022-23642-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 11/03/2022] [Indexed: 02/06/2023] Open
Abstract
Based on the European Union Basic Safety Standards to protect people against exposure to ionizing radiation, establishing and addressing the reference levels for indoor radon concentrations is necessary. Therefore, the indoor radon concentration should be monitored and control in dwelling and workplaces. However, proper ventilation and sustainability are the major factors that influence how healthy the environment in a building is for its occupants. In this paper, the indoor radon distribution in a typical naturally ventilated room under two scenarios (when the door is closed and open) using the computational fluid dynamics (CFD) technique was studied. The CFD code ANSYS Fluent 2020 R1 based on the finite volume method was employed before the simulation results were compared with analytical calculations as well as passive and active measurements. The average radon concentration from the CFD simulation was found to be between 70.21 and 66.25 Bq m-3 under closed and open-door conditions, respectively, at the desired ventilation rate of 1 ACH (Air Changes per Hour). Moreover, the highest concentrations of radon were measured close to the floor and the lowest values were recorded near to the inlet, resulting in the airflow velocity profile. The simulation results were in good agreement with the maxima of 19% and 7% compared to analytical calculations at different indoor air velocities in the open- and closed-door scenarios, respectively. The measured radon concentrations obtained by the active measurements also fitted well with the CFD results, for example, with a relative standard deviation of around 7% and 2% when measured by AlphaGUARD and RAD7 monitors at a height of 1.0 m above the ground in the open-door scenario. From the simulation results, the effective dose received by an individual from the indoor air of the workplace was also calculated.
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Affiliation(s)
- Mohammademad Adelikhah
- grid.7336.10000 0001 0203 5854Institute of Radiochemistry and Radioecology, University of Pannonia, Veszprém, 8200 Hungary
| | - Morteza Imani
- grid.412502.00000 0001 0686 4748Engineering Department, G.C, Shahid Beheshti University, P.O. Box: 1983963113, Tehran, Iran
| | - Tibor Kovács
- grid.7336.10000 0001 0203 5854Institute of Radiochemistry and Radioecology, University of Pannonia, Veszprém, 8200 Hungary
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4
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Agarwal TK, Mishra R, Sapra BK. A CFD-based approach to study the deposition and distribution behaviour of 212Pb in a calibration chamber. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:46950-46959. [PMID: 36735138 DOI: 10.1007/s11356-023-25499-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 01/18/2023] [Indexed: 02/04/2023]
Abstract
Among the several aspects of decay products behavior, deposition is of special significance because of its prominent role in the activity removal from the environment, which eventually results in the occurrence of decay product disequilibrium with the parent gas. This point is particularly important in case of thoron dosimetry where thoron progeny 212Pb accounts for the most of the radiological dose. The deposition depends on the size distribution of decay products and the structure of air turbulence at the air-surface interface. In the present work, the effect of varying air-flow (fan speed) and aerosol count median diameter (CMD) was studied on the deposition and distribution profile of 212Pb using computational fluid dynamics (CFD). The simulations have been carried out in a cubical calibration chamber of volume 8 m3, facilitated at RP&AD, BARC. Simulated results showed that the increase of total depositional loss rate of attached fraction of 212Pb due to increase of the fan speed was significant for CMD up to 400 nm, beyond which this effect started becoming less prominent with increasing diameter. Besides, a minimum of the total depositional loss rate curve was seen to be shifted to the higher CMD with increase of the fan speed. CFD results were found to be in good agreement with experimental observations obtained in the controlled conditions with thoron source.
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Affiliation(s)
- Tarun Kumar Agarwal
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India. .,Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400085, India. .,Global Centre for Nuclear Energy Partnership, Bahadurgarh, Haryana, 124505, India.
| | - Rosaline Mishra
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India.,Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - Balvinder Kaur Sapra
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India.,Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
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5
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Agarwal TK, Kanse SD, Mishra R, Sapra BK. A CFD based approach to assess the effect of environmental parameters on decay product-aerosol attachment coefficient. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-022-08402-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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6
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Agarwal TK, Gaware JJ, Sapra BK. A CFD-based approach to optimize operating parameters of a flow-through scintillation cell for measurement of 220Rn in indoor environments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:16404-16417. [PMID: 34648166 DOI: 10.1007/s11356-021-16780-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
The measurements and monitoring of 222Rn/220Rn have been of emerging interest in occupational environments particularly in radium/thorium handling facilities and environments with monazite deposits for the inhalation dosimetry. The performance of a flow-through Lucas scintillation cell (LSC) for long run 220Rn measurements, depends upon the exact distribution pattern of 220Rn and its decay products in the LSC which can vary with the design of inlet path and flow rates. In this work, the CFD technique has been used to study the concentration profiles of 220Rn and its decay products in LSC for varying flow rates and inlet needle lengths. The variation of alpha production efficiency (ηα) is computed and analyzed for each case; aiming to select the best operating range of parameters for the optimum performance of LSC for 220Rn measurements. It is seen that LSC can be operated in the flow rate ranging from 0.6 to 1 lpm with inlet needle length varying from 22.5 to 45 mm for improved sensitivity.
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Affiliation(s)
- Tarun Kumar Agarwal
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India.
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
| | - Jitendra Jalindar Gaware
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - Balvinder Kaur Sapra
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
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7
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Lee CW, Kim HR. SPATIAL DISTRIBUTION ANALYSIS AND DOSE ASSESSMENT OF THE RADON EMITTED FROM THE MONAZITE-CONTAINING MATTRESS IN GENERAL RESIDENTIAL SPACE BY CFD METHODS. RADIATION PROTECTION DOSIMETRY 2022; 198:8-15. [PMID: 35021229 DOI: 10.1093/rpd/ncab181] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 10/31/2021] [Accepted: 11/19/2021] [Indexed: 06/14/2023]
Abstract
Recently, mattresses produced from radon-emitting monazite raw materials in the manufacturing process were found to be releasing radon, and a survey by the Korean Nuclear Safety and Security Commission indicated that some of these products exceeded safety standards. In this study, the distribution of the radon resulting from radon-emitting mattresses was evaluated. The computational fluid dynamics (CFD) code FLUENT was used to analyze the distribution of radon in a general living space, and to assess the exposures of residents. Drawings from the Korea Land and Housing Corporation were analyzed to determine the layout and geometry of the general residential space. Based on the results of the CFD simulation, the distribution of radon in the general residential space was analyzed based on the direction of ventilation and distance from the source. The dose was evaluated to analyze the radiological safety, and was determined to be less than 0.101 mSv per year. These results were in accordance with the reference level of 10 mSv from the International Commission on Radiological Protection recommendation and the annual dose limit of 1 mSv per year for processed products in South Korea.
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Affiliation(s)
- Choong Wie Lee
- Integrated Radwaste Management Team, Korea Atomic Energy Research Institute, Daejeon 34057 South Korea
| | - Hee Reyoung Kim
- Department of Nuclear Energy, Ulsan National Institute of Science and Technology, Ulsan 44919 South Korea
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8
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A Computational Fluid Dynamics code for aerosol and decay-product studies in indoor environments. J Radioanal Nucl Chem 2021. [DOI: 10.1007/s10967-021-07877-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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9
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Devi V, Chauhan RP. Implications on dose estimation and dispersion patterns of thoron in a typical indoor environment. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2021; 60:309-316. [PMID: 33689025 DOI: 10.1007/s00411-021-00899-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 02/20/2021] [Indexed: 06/12/2023]
Abstract
A model that describes the pollutant sources/sinks and inlet-outlet can help to assess the indoor exposure. Short half-life of radioactive thoron (220Rn) makes it vital and an interesting element to study its dispersion behavior. This work presents an extensive depiction of the influence of indoor environment thoron dispersion under fixed boundary conditions within the volume domain of 90 m3 using computational fluid dynamics (CFD) software. For the desirable air flow, inlet and outlet are considered in the room and the k-ɛ model is used. The thoron distribution is studied at different locations and different heights to cover the whole room. Obtained dispersion patterns vary at different locations and indicate non-uniformity of thoron level with elevated values in the room corners. Mean concentration was found to be 11 Bq/m3 with the exhalation rate of 0.102 Bqm-2 s-1. Some stagnant zones were found especially at the corners where the concentration is almost 5 times the average concentration. Such varying thoron level results in the overestimation and underestimation of the dose. The inhomogeneous behavior of thoron may cause variation in equilibrium factor. A simulated model is beneficial in understanding the radioactive gas behavior and has its importance in planning to find the correct dose estimation and, therefore, the best mitigation techniques.
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Affiliation(s)
- Vandana Devi
- Department of Physics, National Institute of Technology, Kurukshetra, Haryana, 136119, India
| | - R P Chauhan
- Department of Physics, National Institute of Technology, Kurukshetra, Haryana, 136119, India.
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10
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Agarwal TK, Sahoo BK, Shetty T, Gaware JJ, Kumara S, Karunakara N, Sapra BK, Datta D. Numerical simulation of 222Rn profiling in an experimental chamber using CFD technique. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 220-221:106298. [PMID: 32560887 DOI: 10.1016/j.jenvrad.2020.106298] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 03/03/2020] [Accepted: 05/03/2020] [Indexed: 06/11/2023]
Abstract
Measurement of indoor 222Rn concentration and interpretation of distribution patterns are important for inhalation dosimetry in occupational and residential areas. Experimental determination of 222Rn concentration distribution and estimation of inhalation doses depend on the underlying aspects such as calibration of the detectors, accuracy of the techniques etc. Therefore, 222Rn concentration distribution needs to be very well understood in a closed domain for the controlled studies. In the recent times, Computational fluid dynamics (CFD) technique has gained a lot of attention for the prediction and visualization of indoor 222Rn concentration profiles and their mixing ability in the domain. The present study aims to simulate the effect of forced mixing on the 222Rn concentration profile in a 22 m3 experimental chamber. This chamber is designed for carrying out the controlled experiments, calibration and inter-comparison studies of various types of 222Rn detectors. Effect of different parameters such as time, flow rates, fan-off and fan-on conditions have been studied on the transient response, extent of the air mixing patterns and subsequently on 222Rn concentration profile in the chamber. Further, Non uniformity index (NUI) is introduced as a measure of the uniformity of the distribution in the closed domain. NUI is estimated for different cases in order to efficiently interpret the effect of above mentioned parameters on 222Rn profile in the chamber. This study will be useful to represent the turbulent conditions in real indoor domains and occupational facilities as U-mines during calibration and inter-comparison exercises of different 222Rn detectors.
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Affiliation(s)
- Tarun K Agarwal
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - B K Sahoo
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - Trilochana Shetty
- Centre for Advanced Research in Environmental Radioactivity (CARER), Mangalore University, Mangalagangothri, Karnataka, 574199, India
| | - J J Gaware
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - Sudeep Kumara
- Centre for Advanced Research in Environmental Radioactivity (CARER), Mangalore University, Mangalagangothri, Karnataka, 574199, India
| | - N Karunakara
- Centre for Advanced Research in Environmental Radioactivity (CARER), Mangalore University, Mangalagangothri, Karnataka, 574199, India
| | - B K Sapra
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
| | - D Datta
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
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11
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CFD-based simulation and experimental verification of 222Rn distribution in a walk-in type calibration chamber. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06957-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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Serge Didier TS, Tokonami S, Hosoda M, Suzuki T, Kudo H, Bouba O. Simultaneous measurements of indoor radon and thoron and inhalation dose assessment in Douala City, Cameroon. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2019; 55:499-510. [PMID: 31394926 DOI: 10.1080/10256016.2019.1649258] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 07/13/2019] [Indexed: 06/10/2023]
Abstract
Radon, thoron and associated progeny measurements have been carried out in 71 dwellings of Douala city, Cameroon. The radon-thoron discriminative detectors (RADUET) were used to estimate the radon and thoron concentration, while thoron progeny monitors measured equilibrium equivalent thoron concentration (EETC). Radon, thoron and thoron progeny concentrations vary from 31 ± 1 to 436 ± 12 Bq m-3, 4 ± 7 to 246 ± 5 Bq m-3, and 1.5 ± 0.9 to 13.1 ± 9.4 Bq m-3. The mean value of the equilibrium factor for thoron is estimated at 0.11 ± 0.16. The annual effective dose due to exposure to indoor radon and progeny ranges from 0.6 to 9 mSv a-1 with an average value of 2.6 ± 0.1 mSv a-1. The effective dose due to the exposure to thoron and progeny vary from 0.3 to 2.9 mSv a-1 with an average value of 1.0 ± 0.4 mSv a-1. The contribution of thoron and its progeny to the total inhalation dose ranges from 7 to 60 % with an average value of 26 %; thus their contributions should not be neglected in the inhalation dose assessment.
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Affiliation(s)
- Takoukam Soh Serge Didier
- Nuclear Physics Laboratory, Faculty of Science, University of Yaoundé I , Yaoundé , Cameroon
- Nuclear Technology Section, Institute of Geological and Mining Research , Yaoundé , Cameroon
| | - Shinji Tokonami
- Department of Radiation Physics, Institute of Radiation Emergency Medicine, Hirosaki University , Hirosaki City , Japan
| | - Masahiro Hosoda
- Department of Radiation Science, Graduate School of Health Sciences, Hirosaki University , Hirosaki City, Aomori , Japan
| | - Takahito Suzuki
- Department of Radiation Science, Graduate School of Health Sciences, Hirosaki University , Hirosaki City, Aomori , Japan
| | - Hiromi Kudo
- Department of Radiation Science, Graduate School of Health Sciences, Hirosaki University , Hirosaki City, Aomori , Japan
| | - Oumarou Bouba
- Nuclear Physics Laboratory, Faculty of Science, University of Yaoundé I , Yaoundé , Cameroon
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13
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CFD simulations to study the effect of ventilation rate on 220Rn concentration distribution in a test house. Radiat Phys Chem Oxf Engl 1993 2019. [DOI: 10.1016/j.radphyschem.2019.04.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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14
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Visnuprasad AK, Reby Roy KE, Jojo PJ, Sahoo BK. Comparison of results from indoor radon measurements using active and passive methods with those from mathematical modeling. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2019; 58:345-352. [PMID: 31250094 DOI: 10.1007/s00411-019-00804-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Accepted: 06/15/2019] [Indexed: 06/09/2023]
Abstract
Computational fluid dynamics (CFD) has been used to simulate the distribution of indoor radon concentration in a naturally ventilated room. Finite volume method was employed in CFD code for the simulation of indoor radon. The simulation results were validated at 34 points in a matrix of two horizontal planes (y = 1.3 m and y = 2.1 m) using passive pinhole dosimeters and at six points using an active scintillation radon monitor. The CFD results were found to exhibit an excellent correlation with the measured values. It is concluded that CFD analysis is a powerful tool to visualize indoor radon distribution.
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Affiliation(s)
- A K Visnuprasad
- Center for Advanced Research in Physical Sciences (CARPS), Fatima Mata National College (Autonomous), Kerala, 691001, India
| | - K E Reby Roy
- Department of Mechanical Engineering, T.K.M College of Engineering, Kerala, 691005, India
| | - P J Jojo
- Center for Advanced Research in Physical Sciences (CARPS), Fatima Mata National College (Autonomous), Kerala, 691001, India.
- Department of Applied Physics, Papua New Guinea University of Technology, Lae, Papua New Guinea.
| | - B K Sahoo
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India
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15
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Rabi R, Oufni L, Amrane M. Modeling of indoor 222Rn distribution in ventilated room and resulting radiation doses measured in the respiratory tract. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2019. [DOI: 10.1016/j.jrras.2017.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- R. Rabi
- Sultan Moulay Slimane University, Faculty of Sciences and Techniques, Department of Physics - LPM, B.P.523, Beni-Mellal, 23000, Morocco
| | - L. Oufni
- Sultan Moulay Slimane University, Faculty of Sciences and Techniques, Department of Physics - LPM, B.P.523, Beni-Mellal, 23000, Morocco
| | - M. Amrane
- Sultan Moulay Slimane University, Faculty of Sciences and Techniques, Department of Physics - LPM, B.P.523, Beni-Mellal, 23000, Morocco
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16
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Hu J, Yang G, Hegedűs M, Iwaoka K, Hosoda M, Tokonami S. Numerical modeling of the sources and behaviors of 222Rn, 220Rn and their progenies in the indoor environment-A review. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 189:40-47. [PMID: 29573590 DOI: 10.1016/j.jenvrad.2018.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 03/18/2018] [Accepted: 03/18/2018] [Indexed: 06/08/2023]
Abstract
222Rn, 220Rn and their short-lived progenies are well known radioactive indoor pollutants, identified as the leading environmental cause of lung cancer next to smoking. Apart from the conventional measurement methods, numerical modeling methods are developed to simulate their physical and decay processes in 222Rn and 220Rn's life cycle, estimate their levels, concentration distributions, as well as effects of control strategies in the indoor environment. In this article, we summarized the numerical models used to illustrate the physical processes of each source of 222Rn and 220Rn entry into the indoor environment, and the application of Jacobi room models and CFD (Computational Fluid Dynamic) models used to present the behaviors of indoor 222Rn, 220Rn and their progenies. Furthermore, we consider that the development of numerical modeling of 222Rn and 220Rn would have a bright prospect in the directions of stochastic methods based on a steady-state model, the fine simulation of the time-dependent model as well as the multi-dimension model.
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Affiliation(s)
- Jun Hu
- Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan; Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Guosheng Yang
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Miklós Hegedűs
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Kazuki Iwaoka
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Masahiro Hosoda
- Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Shinji Tokonami
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan.
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17
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Evaluation of indoor radon equilibrium factor using CFD modeling and resulting annual effective dose. Radiat Phys Chem Oxf Engl 1993 2018. [DOI: 10.1016/j.radphyschem.2017.10.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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18
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Visnuprasad AK, Jaikrishnan G, Sahoo BK, Pereira CE, Jojo PJ. CONTRIBUTION OF THORON AND PROGENY TOWARDS INHALATION DOSE IN A THORIUM ABUNDANT BEACH ENVIRONMENT. RADIATION PROTECTION DOSIMETRY 2018; 178:405-413. [PMID: 28981889 DOI: 10.1093/rpd/ncx126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 08/10/2017] [Indexed: 06/07/2023]
Abstract
In an environment having thorium rich soil the activity concentration of thoron in soil gas and ground-level outside air is comparable to that to radon. Recent reports indicate that in terms of the energy of the alpha particle decays of thoron's progeny, its concentration in indoor air is significant, typically about half that due to radon progeny. We made a detailed radiometric profiling of inhalation dose to the population of the high background radiation area in the west southern coastal region of India. Here we report the results obtained from the long-term time integrated passive measurements of radon, thoron and their progeny concentrations in the high background radiation areas of Chavara and Neendakara hamlets of Kollam district. The equilibrium factors of radon and thoron with their progeny were determined for the region and was consistent with a previous study. The estimated value of total annual inhalation dose in the region ranged from 0.4 ± 0.06 to 3.7 ± 0.6 mSv y-1. The annual effective dose due to thoron and thoron progeny contributes ~35% to the total inhalation dose which means that thoron and its progeny is significant in assessing the radiation dose to the public.
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Affiliation(s)
- A K Visnuprasad
- Department of Physics, Fatima Mata National College, Kollam, India
| | - G Jaikrishnan
- Low Level Radiation Research Laboratory, Bhabha Atomic Research Centre, Kollam, India
| | - B K Sahoo
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Kollam, India
| | - C E Pereira
- Department of Physics, Fatima Mata National College, Kollam, India
| | - P J Jojo
- Department of Physics, Fatima Mata National College, Kollam, India
- Department of Applied Physics, The Papua New Guinea University of Technology, Lae, Papua New Guinea
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Iwaoka K, Yajima K, Suzuki T, Yonehara H, Hosoda M, Tokonami S, Kanda R. Investigation of Natural Radioactivity in a Monazite Processing Plant in Japan. HEALTH PHYSICS 2017; 113:220-224. [PMID: 28749812 DOI: 10.1097/hp.0000000000000692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Monazite is a naturally occurring radioactive material that is processed for use in a variety of domestic applications. At present, there is little information available on potential radiation doses experienced by people working with monazite. The ambient dose rate and activity concentration of natural radionuclides in raw materials, products, and dust in work sites as well as the Rn and Rn concentrations in work sites were measured in a monazite processing plant in Japan. Dose estimations for plant workers were also conducted. The activity concentration of the U series in raw materials and products for the monazite processing plant was found to be higher than the relevant values described in the International Atomic Energy Agency Safety Standards. The ambient dose rates in the raw material yard were higher than those in other work sites. Moreover, the activity concentrations of dust in the milling site were higher than those in other work sites. The Rn concentrations in all work sites were almost the same as those in regular indoor environments in Japan. The Rn concentrations in all work sites were much higher than those in regular indoor environments in Japan. The maximum value of the effective dose for workers was 0.62 mSv y, which is lower than the reference level range (1-20 mSv y) for abnormally high levels of natural background radiation published in the International Commission of Radiological Protection Publication 103.
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Affiliation(s)
- Kazuki Iwaoka
- *National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan; †Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Honcho, Hirosaki, Aomori 036-8564, Japan; ‡National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan; §Hirosaki University Graduate School of Health Sciences, 66-1 Honcho, Hirosaki, Aomori 036-8564, Japan
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20
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Iwaoka K, Hosoda M, Yajima K, Tokonami S. Measurements of radon exhalation rate in NORM used as consumer products in Japan. Appl Radiat Isot 2017; 126:304-306. [PMID: 28153437 DOI: 10.1016/j.apradiso.2017.01.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/21/2016] [Accepted: 01/23/2017] [Indexed: 11/28/2022]
Abstract
Twenty-five beauty products known to contain natural radionuclides were collected, and their 222Rn mass exhalation rates were measured. The effective doses to workers due to 222Rn exhaled from these products were estimated. The 222Rn mass exhalation rates of these products were below 177 μBq kg-1 s-1 and were almost identical to those of natural rocks in Japan. The maximum effective dose of 222Rn exhaled from these products was 71 μSv y-1.
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Affiliation(s)
- Kazuki Iwaoka
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Honcho, Hirosaki, Aomori 036-8564, Japan; National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Sciences and Technology, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan.
| | - Masahiro Hosoda
- Hirosaki University Graduate School of Health Sciences, 66-1 Honcho, Hirosaki, Aomori 036-8564, Japan
| | - Kazuaki Yajima
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Sciences and Technology, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan
| | - Shinji Tokonami
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Honcho, Hirosaki, Aomori 036-8564, Japan
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21
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Dieguez-Elizondo PM, Gil-Lopez T, O'Donohoe PG, Castejon-Navas J, Galvez-Huerta MA. An analysis of the radioactive contamination due to radon in a granite processing plant and its decontamination by ventilation. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 167:26-35. [PMID: 27876160 DOI: 10.1016/j.jenvrad.2016.11.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 10/28/2016] [Accepted: 11/13/2016] [Indexed: 06/06/2023]
Abstract
This work focuses on studying concentration distribution of 222Rn radioisotope in a granite processing plant. Using Computational Fluid Dynamic Techniques (CFD), the exposure of the workers to radiation was assessed and, in order to minimise this exposure, different decontamination scenarios using ventilation were analysed. Natural ventilation showed not sufficient to maintain radon concentration below acceptable limits, so a forced ventilation was used instead. Position of the granite blocks also revealed as a determining factor in the radioactive level distribution. Thus, a correct layout of the stored material and an adequate ventilation system can guarantee free of exposure to radiation zones within the studied workshop. This leads to a drastic fall in the exposure of the workers and consequently minimises their risk of developing aggressive illness like lung cancer.
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Affiliation(s)
| | - Tomas Gil-Lopez
- Madrid Polytechnic University, Avda. Juan de Herrera, 6, 28040 Madrid, Spain.
| | - Paul G O'Donohoe
- Madrid Polytechnic University, Avda. Juan de Herrera, 6, 28040 Madrid, Spain
| | - Juan Castejon-Navas
- Madrid Polytechnic University, Avda. Juan de Herrera, 6, 28040 Madrid, Spain
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22
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de With G, de Jong P. Impact from indoor air mixing on the thoron progeny concentration and attachment fraction. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 158-159:56-63. [PMID: 27064565 DOI: 10.1016/j.jenvrad.2016.02.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 02/19/2016] [Accepted: 02/19/2016] [Indexed: 06/05/2023]
Abstract
Despite the considerable amount of work in the field of indoor thoron exposure, little studies have focussed on mitigation strategies to reduce exposure to thoron and its progeny. For this reason an advanced computer model has been developed that describes the dispersion and aerosol modelling from first principal using Computational Fluid Dynamics. The purpose of this study is to investigate the mitigation effects from air mixing on the progeny concentration and attachment with aerosols. The findings clearly demonstrate a reduction in thoron progeny concentration due to air mixing. The reduction in thoron progeny is up to 60% when maximum air mixing is applied. In addition there is a reduction in the unattached fraction from 1.2% under regular conditions to 0.3% in case of maximum mixing.
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Affiliation(s)
- G de With
- Nuclear Research and Consultancy Group (NRG), Utrechtseweg 310, NL-6800 ES Arnhem, The Netherlands.
| | - P de Jong
- Nuclear Research and Consultancy Group (NRG), Utrechtseweg 310, NL-6800 ES Arnhem, The Netherlands
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23
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Agarwal TK, Joshi M, Sahoo BK, Kanse SD, Sapra BK. Effect of 220Rn gas concentration distribution on its transmission from a delay chamber: evolving a CFD-based uniformity index. RADIATION PROTECTION DOSIMETRY 2016; 168:546-552. [PMID: 26152566 DOI: 10.1093/rpd/ncv361] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 06/05/2015] [Indexed: 06/04/2023]
Abstract
(220)Rn mitigation can be achieved by delay chamber technique, which relies on the advantage of its short half-life. However, flow rate as well as inlet-outlet position for the delay chamber can have a significant impact on (220)Rn concentration distribution patterns and hence transmission factor. In the present study, computational fluid dynamics simulations to estimate the concentration distribution has been carried out in a chamber of 0.5 m(3) for the combination of six different inlet-outlet positions and five different flow rates. Subsequently, the transmission factor (TF) for the chamber was evaluated and found to be highly dependent on the flow rate and inlet-outlet positions. For ease of scale up, the dependency of TF on the flow rate and the inlet-outlet positions is best summarised by relative transmission factor (RTF), which is the ratio of the TFs for the case of inlet and outlet on different faces to that on the same face.
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Affiliation(s)
- T K Agarwal
- Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - M Joshi
- Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - B K Sahoo
- Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - S D Kanse
- Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - B K Sapra
- Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
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24
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Lee JE, Park HC, Choi HS, Cho SY, Jeong TY, Roh SC. A numerical study on the performance evaluation of ventilation systems for indoor radon reduction. KOREAN J CHEM ENG 2016. [DOI: 10.1007/s11814-015-0214-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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25
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Chauhan N, Chauhan RP. Active-passive measurements and CFD based modelling for indoor radon dispersion study. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2015; 144:57-61. [PMID: 25817925 DOI: 10.1016/j.jenvrad.2015.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 02/24/2015] [Accepted: 03/06/2015] [Indexed: 06/04/2023]
Abstract
Computational fluid dynamics (CFD) play a significant role in indoor pollutant dispersion study. Radon is an indoor pollutant which is radioactive and inert gas in nature. The concentration level and spatial distribution of radon may be affected by the dwelling's ventilation conditions. Present work focus at the study of indoor radon gas distribution via measurement and CFD modeling in naturally ventilated living room. The need of the study is the prediction of activity level and to study the effect of natural ventilation on indoor radon. Two measurement techniques (Passive measurement using pin-hole dosimeters and active measurement using continuous radon monitor (SRM)) were used for the validation purpose of CFD results. The CFD simulation results were compared with the measurement results at 15 points, 3 XY planes at different heights along with the volumetric average concentration. The simulation results found to be comparable with the measurement results. The future scope of these CFD codes is to study the effect of varying inflow rate of air on the radon concentration level and dispersion pattern.
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Affiliation(s)
- Neetika Chauhan
- Department of Physics, National Institute of Technology, Kurukshetra 136119, India.
| | - R P Chauhan
- Department of Physics, National Institute of Technology, Kurukshetra 136119, India
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26
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Chauhan N, Chauhan RP, Joshi M, Agarwal TK, Aggarwal P, Sahoo BK. Study of indoor radon distribution using measurements and CFD modeling. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2014; 136:105-111. [PMID: 24929505 DOI: 10.1016/j.jenvrad.2014.05.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 04/16/2014] [Accepted: 05/22/2014] [Indexed: 06/03/2023]
Abstract
Measurement and/or prediction of indoor radon ((222)Rn) concentration are important due to the impact of radon on indoor air quality and consequent inhalation hazard. In recent times, computational fluid dynamics (CFD) based modeling has become the cost effective replacement of experimental methods for the prediction and visualization of indoor pollutant distribution. The aim of this study is to implement CFD based modeling for studying indoor radon gas distribution. This study focuses on comparison of experimentally measured and CFD modeling predicted spatial distribution of radon concentration for a model test room. The key inputs for simulation viz. radon exhalation rate and ventilation rate were measured as a part of this study. Validation experiments were performed by measuring radon concentration at different locations of test room using active (continuous radon monitor) and passive (pin-hole dosimeters) techniques. Modeling predictions have been found to be reasonably matching with the measurement results. The validated model can be used to understand and study factors affecting indoor radon distribution for more realistic indoor environment.
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Affiliation(s)
- Neetika Chauhan
- Department of Physics, National Institute of Technology, Kurukshetra 136119, India.
| | - R P Chauhan
- Department of Physics, National Institute of Technology, Kurukshetra 136119, India
| | - M Joshi
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - T K Agarwal
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Praveen Aggarwal
- Department of Civil Engineering, National Institute of Technology, Kurukshetra 136119, India
| | - B K Sahoo
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
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27
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Agarwal TK, Sahoo BK, Gaware JJ, Joshi M, Sapra BK. CFD based simulation of thoron ((220)Rn) concentration in a delay chamber for mitigation application. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2014; 136:16-21. [PMID: 24860913 DOI: 10.1016/j.jenvrad.2014.05.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 04/16/2014] [Accepted: 05/03/2014] [Indexed: 06/03/2023]
Abstract
The release of (220)Rn gas (conventionally referred to as thoron) is an issue of concern from the radiological point of view for occupational environments pertaining to the thorium fuel cycle. Studies for understanding its release and developing systems to control it are crucial for exposure control research. A thorough study of the "Delay Volume Technique" for mitigation of (220)Rn has been carried out. Experiments have been carried out with (220)Rn source and associated measurement system in a cubical chamber (delay chamber) of 0.5 m(3) volume. For different flow conditions and inlet-outlet positions, (220)Rn transmission factor has been obtained. Computational Fluid Dynamics (CFD) technique has been employed for these experimental conditions and the simulated transmission factors have been compared. The results show that the flow and the position of the inlet and outlet play an imperative role in the transportation, mixing and subsequent mitigation of thoron inside the chamber. Predictive capability of CFD technique for such delay volume experiments has been validated in this work. A comparison has been made with uniform mixing model and it is found that the results of simulation differ appreciably from that of uniform mixing model at the tested flow regime.
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Affiliation(s)
- T K Agarwal
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - B K Sahoo
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - J J Gaware
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - M Joshi
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - B K Sapra
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
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28
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Iwaoka K, Tabe H, Suzuki T, Yonehara H. Occupational exposure to natural radiation in zirconium refractory plants in Japan. HEALTH PHYSICS 2013; 104:151-157. [PMID: 23274817 DOI: 10.1097/hp.0b013e31826f55f8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The authors measured the ambient dose rate and activity concentration of natural radionuclides in raw materials, products, and aerosols on worksites, as well as the (222)Rn and (220)Rn concentrations in an unshaped refractory, a shaped refractory, and an electrocast refractory plant processing zirconium ore in Japan. Estimations were made of the effective doses to plant workers. The activity concentration of the (238)U series in raw materials and products in the refractory plants was higher than the critical values (10 Bq g(-1) for (40)K and 1 Bq g(-1) for all other radionuclides of natural origin) specified in the International Atomic Energy Agency Safety Guide. The ambient dose rate in the raw material warehouse of the electrocast refractory plant was 0.75 μSv h(-1), which was the highest among all the worksites at all the refractory plants studied. The activity concentrations of aerosols in the product-output site of the unshaped refractory plant was 0.0015 Bq m for U and 0.00078 Bq m(-3) for (232)Th, which were the highest of all the worksites for all refractory plants. The indoor (222)Rn and (220)Rn concentrations in all worksites of all the refractory plants were almost the same levels as those in everyday indoor places in Japan. The maximum value of the effective dose to workers was 430 μSv y(-1), which was lower than the intervention exemption level (1,000 μSv y(-1)) specified in ICRP Publication 82.
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Affiliation(s)
- Kazuki Iwaoka
- Research Center for Radiation Protection, National Institute of Radiological Sciences 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan.
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29
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Markovic VM, Stevanovic N, Nikezic D. Doses from beta radiation in sensitive layers of human lung and dose conversion factors due to 222Rn/220Rn progeny. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2011; 50:431-440. [PMID: 21556846 DOI: 10.1007/s00411-011-0369-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 04/24/2011] [Indexed: 05/27/2023]
Abstract
Great deal of work has been devoted to determine doses from alpha particles emitted by (222)Rn and (220)Rn progeny. In contrast, contribution of beta particles to total dose has been neglected by most of the authors. The present work describes a study of the detriment of (222)Rn and (220)Rn progeny to the human lung due to beta particles. The dose conversion factor (DCF) was introduced to relate effective dose and exposure to radon progeny; it is defined as effective dose per unit exposure to inhaled radon or thoron progeny. Doses and DCFs were determined for beta radiation in sensitive layers of bronchi (BB) and bronchioles (bb), taking into account inhaled (222)Rn and (220)Rn progeny deposited in mucus and cilia layer. The nuclei columnar secretory and short basal cells were considered to be sensitive target layers. For dose calculation, electron-absorbed fractions (AFs) in the sensitive layers of the BB and bb regions were used. Activities in the fast and slow mucus of the BB and bb regions were obtained using the LUNGDOSE software developed earlier. Calculated DCFs due to beta radiation were 0.21 mSv/WLM for (222)Rn and 0.06 mSv/WLM for (220)Rn progeny. In addition, the influence of Jacobi room parameters on DCFs was investigated, and it was shown that DCFs vary with these parameters by up to 50%.
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Affiliation(s)
- V M Markovic
- Department of Physics, Faculty of Science, University of Kragujevac, R. Domanovic 12, 34000, Kragujevac, Serbia
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30
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de With G, de Jong P. CFD modelling of thoron and thoron progeny in the indoor environment. RADIATION PROTECTION DOSIMETRY 2011; 145:138-144. [PMID: 21447502 DOI: 10.1093/rpd/ncr056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Thoron (220Rn) exhalation from building materials has become increasingly recognised as a potential source for radiation exposure in residences. However, contrary to radon (222Rn), limited information on thoron exposure is available. The purpose of this study is to estimate the concentration of thoron and its progeny products in a typical Dutch living room using computational fluid dynamics. The predicted thoron concentration is ∼9 Bq m(-3) using a source term of 14 Bq s(-1) for the thoron exhalation from building materials. The concentration varies from 15 Bq m(-3) near the building materials to 2.7 Bq m(-3) in the centre of the living room. The mean effective dose from thoron progeny is calculated as 0.09 mSv y(-1), with a total effective dose from radon and thoron progeny of 0.38 mSv y(-1).
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Affiliation(s)
- G de With
- Nuclear Research and consultancy Group, PO Box 9034, NL-6800 ES Arnhem, The Netherlands.
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31
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Chen J, Moir D, Sorimachi A, Tokonami S. Characteristics of thoron and thoron progeny in Canadian homes. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2011; 50:85-89. [PMID: 20872008 DOI: 10.1007/s00411-010-0338-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 09/14/2010] [Indexed: 05/29/2023]
Abstract
Naturally occurring isotopes of radon in indoor air are identified as the second leading cause of lung cancer after tobacco smoking. Radon-222 (radon gas) and radon-220 (thoron gas) are the most common isotopes of radon. While the radon equilibrium factor is well established, the equilibrium factor between thoron progeny and thoron gas is still not well known. Thoron gas and progeny concentrations were determined in the lowest floors of 138 Canadian homes simultaneously. While thoron gas was only detectable in about 52% of the homes, thoron progeny concentrations were measured in every home surveyed. Thoron concentrations, thoron progeny concentrations, and the equilibrium factors varied widely and were log-normally distributed. With a 3 months simultaneous measurement of thoron and thoron progeny concentrations, the equilibrium factor was determined to be 0.024 with a geometric standard deviation of 2.7.
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Affiliation(s)
- Jing Chen
- Radiation Protection Bureau, Health Canada, 775 Brookfield Road, Ottawa, ON, Canada.
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32
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Chambers DB. Thoron and decay products, beyond UNSCEAR 2006 Annex E. RADIATION PROTECTION DOSIMETRY 2010; 141:351-356. [PMID: 20966204 DOI: 10.1093/rpd/ncq224] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Uranium and thorium series radionuclides are present in all soils and rocks. Thus, radon and thoron, the radioactive noble gases originating in the uranium ((238)U) and thorium ((232)Th) decay chains is ubiquitous and everyone is exposed to both radon and thoron gases and their particulate radioactive decay products. As described in UNSCEAR Annex E (2006), radon and its decay products have been recognised for many years as a hazard to underground miners. More recently, the risks from exposure to residential radon have been demonstrated through residential case-control epidemiological studies. However, as discussed by UNSCEAR, exposures to thoron and its decay products have often been relatively ignored. Moreover, unlike radon the effects of exposure to thoron and its decay products are not available from epidemiology and thus, a dosimetric approach is required to assess risks. UNSCEAR continues to recommend the use of a dose conversion factor for thoron decay products of 40 nSv (Bq h m(-3))(-1). UNSCEAR Annex E suggests there is an emerging problem, namely, that the contribution of (220)Rn (thoron) gas to the (222)Rn (radon) gas measurement signal is not well known. Until recently, this has largely been ignored. This is an important consideration as measurements at work and homes are the basis for investigating lung cancer exposure-response relationships. Based on UNSCEAR Annex E, this paper provides an overview of the sources and levels of thoron and its associated decay products at home and work. In addition, this paper provides an overview of the thoron dosimetry considered by UNSCEAR Annex E and some recent results.
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Affiliation(s)
- D B Chambers
- SENES Consultants Limited, Unit 12, Richmond Hill, ON, Canada.
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Stevanovic N, Markovic V, Urosevic V, Nikezic D. Determination of parameters of the Jacobi room model using the Brownian motion model. HEALTH PHYSICS 2009; 96:48-54. [PMID: 19066486 DOI: 10.1097/01.hp.0000326328.47540.6d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Parameters of the Jacobi room model were estimated with simulation of Brownian motion. Deposition on internal room surfaces and attachment of progeny atoms to three modally distributed aerosols were taken into account. The values of parameters were presented as functions of aerosol concentrations. The deposition rate of an unattached progeny was estimated in the range 30-47 h-1; the deposition rate of an attached progeny was very small and its range is 0.0007-0.004 h-1; the attachment rate of a progeny is in range 40-170 h-1. The statistical uncertainty was lower than 1%. The ranges of parameters were similar to those reported in literature.
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Affiliation(s)
- N Stevanovic
- Faculty of Science, University of Kragujevac, R. Domanovic 12, 34000 Kragujevac, Serbia
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34
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Urosevic V, Nikezic D, Vulovic S. A theoretical approach to indoor radon and thoron distribution. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2008; 99:1829-1833. [PMID: 18793818 DOI: 10.1016/j.jenvrad.2008.07.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Revised: 06/16/2008] [Accepted: 07/26/2008] [Indexed: 05/26/2023]
Abstract
A model based on the Finite Element Method was developed to simulate indoor behavior of radon ((222)Rn), thoron ((220)Rn) and their progeny, as well as, to calculate their spatial distributions. Since complex physical processes govern the distribution several simplifications were made in the presented model. Different locations of possible radon/thoron sources, diffusion of these gases, their radioactive decay, etc were taken into account. Influences of different parameters on thoron/radon as well as indoor distribution of their progeny, such as the geometry and room dimension, the presence of aerosols and their size distribution expressed through the diffusion coefficient, different kinds of ventilation, etc, were investigated. It has been found that radon is distributed homogeneously, while the thoron concentration is rather inhomogeneous and decreases exponentially with the distance from the source. Regardless of the source distribution, the distribution of radon was homogeneous, except at places near an air inlet and outlet. However, the distribution of thoron depends on the source distribution. If thoron emanates from walls or the floor, its concentration decreases with the distance from the wall. Moreover, the concentration gradient is much larger near walls. This suggests that the actual selection of the site effect should be taken into account when obtaining a representative value of indoor (220)Rn and their progeny for dose assessment. The simulation results of activities and their distribution were in accordance with the results of other studies and experiments.
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Affiliation(s)
- V Urosevic
- Technical Faculty Cacak, University of Kragujevac, Serbia
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Gargioni E, Model R. A simple method for measuring thoron spatial distributions. RADIATION PROTECTION DOSIMETRY 2005; 113:321-325. [PMID: 15755773 DOI: 10.1093/rpd/nch467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A simple but effective method that allows the measurement of the 220Rn spatial distribution in working or living environments using a solid-state detector is presented in this paper. The method is based on measurements of the alpha particles emitted by 216Po (the first 220Rn progeny) directly deposited on the detector surface at different distances from a 220Rn exhalation source. The validity of the method is shown by comparing the results of an experiment, where the 220Rn activity concentration is measured under conditions of diffusion at constant temperature, with finite-element calculations.
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Affiliation(s)
- E Gargioni
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany.
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