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Chen D, Ye Y, Xia M, Shang S, Yan Z, Chung LK. Numerical simulations of radon exhalation from surrounding rocks of single and double underground roadways. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2024; 273:107388. [PMID: 38266320 DOI: 10.1016/j.jenvrad.2024.107388] [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: 08/04/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 01/26/2024]
Abstract
The radon exhalation rate of surrounding rocks in underground roadways is an important parameter in determining radon exhalation capacity and ventilation flowrate for radon removal. By approximating the roadways as thick-walled, porous cylinders, this study investigates radon exhalation from their surrounding rocks via simulations using computational fluid dynamics (CFD). Radon exhalation rates of single and double underground roadways were computed and analysed under different pressure differences, radon diffusion coefficients, permeabilities of rocks, single roadway locations and additional parallel roadway orientation. The radon regulating zone was presented and the effect of pressure difference on it was analysed. By fitting the data from simulation results, an estimation model was obtained for the radon exhalation rate of a single roadway. For two adjacent parallel roadways with a distance greater than or equal to 50m, the model is also suitable for estimating the radon exhalation rate when the rock permeability is less than 1 × 10-14 m2 and the ratio of permeability to diffusion coefficient is less than 5 × 10-9.
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Affiliation(s)
- Daijia Chen
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, Hunan, 421001, PR China; School of Resources and Environment Safety Engineering, University of South China, Hengyang, Hunan, 421001, PR China
| | - Yongjun Ye
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, Hunan, 421001, PR China; School of Resources and Environment Safety Engineering, University of South China, Hengyang, Hunan, 421001, PR China.
| | - Ming Xia
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, Hunan, 421001, PR China; School of Resources and Environment Safety Engineering, University of South China, Hengyang, Hunan, 421001, PR China
| | - Shanwei Shang
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, Hunan, 421001, PR China; School of Resources and Environment Safety Engineering, University of South China, Hengyang, Hunan, 421001, PR China
| | - Zhiguo Yan
- The Fourth Research and Design Engineering Corporation, China National Nuclear Corporation, Shijiazhuang, 050021, PR China
| | - Long Kiu Chung
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI, 48104, USA
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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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