Impact of Decay on the Transport of Radioactive Aerosols in Long Square Tubes
-
摘要: 衰变射线会导致放射性气溶胶颗粒表面电荷积累，进而影响其迁移过程。然而，目前放射性核素输运模拟中并没有考虑衰变的荷电效应。本文基于Python建立颗粒衰变荷电模型，然后提出颗粒衰变荷电、流场耦合方案，并在流体仿真软件Fluent中完成耦合。分别对含106Ru、131I、132Te、137Cs颗粒衰变荷电模型结果进行分析，结果表明颗粒电荷会在较短时间后达到平衡值。在Fluent中模拟含132Te的颗粒在长直方管中的流动，结果表明电场力主要存在于管壁附近，指向颗粒浓度下降方向，这表明衰变荷电会促进气溶胶的扩散，使其更快地充满整个空间。本文的研究为后续放射性核素输运模拟时，对衰变、电场和流场的耦合方案和模拟结果提供参考。Abstract: Decay radiation can cause accumulation of surface charges of radioactive aerosol particles, and then affect their migration process. However, the charge effect of decay is not considered in the current radionuclide transport simulation. In this study, a particle decay charging model was established based on Python, and a coupled scheme of particle decay charging and flow field was proposed and implemented in Fluent. The results of decay charge model of particles containing 106Ru, 131I, 132Te and 137Cs are analyzed respectively, and the results show that the particle charge will reach the equilibrium value in a short time. The flow of particles containing 132Te in a long square tube is simulated in Fluent. The results show that the electric field force mainly exists near the tube wall, pointing to the direction of particle concentration decline, which indicates that decay charge will promote the diffusion of aerosol and fill the whole space more quickly. This study provides a reference for the coupling scheme and simulation results of decay, electric field, and flow field in subsequent simulations of radioactive nuclide transport.
-
Key words:
- Decay /
- Euler-Lagrange method /
- Radionuclide /
- Aerosols /
- Electrostatic force
-
图 1 不同衰变次数下气溶胶颗粒电荷随时间的关系
1e=1.6021766208×10−19 C
Figure 1. Relationship Between Aerosol Particle Charge and Time under Difference Decay Times
图 2 颗粒含有132Te衰变链时颗粒电荷随时间变化
Figure 2. Variation of Particle Charge with Time when the Particle Contains 132Te Decay Chain
图 3 不同浓度下分别含有106Ru、131I、132Te、137Cs核素及衰变子产物时颗粒电荷随时间的变化
工况1—颗粒浓度106 m−3；工况2—颗粒浓度107 m−3；工况3—颗粒浓度108 m−3；工况4—颗粒浓度109 m−3；工况5—颗粒浓度1011 m−3
Figure 3. Variation of Particle Charge with Time for Particles Containing 106Ru, 131I, 132Te, 137Cs Nuclides and their Decay Progeny under Different Concentrations
图 4 颗粒电荷达到平衡时与对应的时间、颗粒浓度的关系
Figure 4. Relationship Between the Maximum Particle Charge and Corresponding Time and Concentration of Particles
图 5 颗粒电荷达到平衡时颗粒电荷与颗粒浓度关系
Figure 5. Relationship between Particle Charge and Particle Concentration when Particle Charge Reaches Equilibrium
表 1 主要核素的衰变链信息
Table 1. Decay Chain Information for the Main Radionuclides
核素 衰变链 衰变常数/s−1 电离率系数 第1代 第2代 第1代 第2代 $ _{\;\;44}^{106}{\text{Ru}}$ ${}_{\;\;44}^{106}{\text{Ru}} \to {}_{\;\;45}^{106}{\text{Rh}} \to {}_{\;\;46}^{106}{\text{Pd}}$ 2.82×10−8 2.33×10−2 110 16286 ${}_{\;\;53}^{131}{\text{I}}$ ${}_{\;\;53}^{131}{\text{I}} \to {}_{\;\;54}^{131}{\text{Xe}}$ 1.00×10−6 1945 ${}_{\;\;52}^{132}{\text{Te}}$ ${}_{\;\;52}^{132}{\text{Te}} \to {}_{\;\;53}^{132}{\text{I}} \to {}_{\;\;54}^{132}{\text{Xe}}$ 2.50×10−6 8.39×10−5 748 5863 ${}_{\;\;55}^{137}{\text{Cs}}$ $ {}_{\; \; 55}^{137}\text{Cs}\to_{\;\;56}^{137 } {{\mathrm{Ba}}}^{\mathrm{m}}\to_{\; \; 56}^{137}{ {\mathrm{Ba}}} $ 7.31×10−10 4.5×10−3 2067 
下载: 导出CSV
表 2 颗粒衰变荷电模型参数设置
Table 2. Parameters Setting for Decay Charging Model
参数 参数值 颗粒直径/μm 1 正离子电迁移速率/(10−4 m2·V−1·s−1) 1.2 负离子电迁移速率/(10−4 m2·V−1·s−1) 1.2 正负离子再结合速率因子/(10−12 m3·s−1) 1.6 背景离子产生速率/(m−3·s−1) 107 气溶胶颗粒浓度/m−3 1011 气溶胶微粒有效密度/(kg·m−3) 2000 每个颗粒最初含有核素个数 5×108
下载: 导出CSV
-
[1] KATATA G, CHINO M, KOBAYASHI T, et al. Detailed source term estimation of the atmospheric release for the Fukushima Daiichi Nuclear Power Station accident by coupling simulations of an atmospheric dispersion model with an improved deposition scheme and oceanic dispersion model[J]. Atmospheric Chemistry and Physics, 2015, 15(2): 1029-1070. doi: 10.5194/acp-15-1029-2015 [2] 李钰,顾卫国,王德忠. 考虑聚并及热泳的微米级气溶胶粒子沉积数值模拟研究[J]. 原子能科学技术,2019, 53(1): 180-186. [3] KIM Y H, YIACOUMI S, TSOURIS C. Surface charge accumulation of particles containing radionuclides in open air[J]. Journal of Environmental Radioactivity, 2015, 143: 91-99. doi: 10.1016/j.jenvrad.2015.02.017 [4] CLEMENT C F, HARRISON R G. The charging of radioactive aerosols[J]. Journal of Aerosol Science, 1992, 23(5): 481-504. doi: 10.1016/0021-8502(92)90019-R [5] GENSDARMES F, BOULAUD D, RENOUX A. Electrical charging of radioactive aerosols—comparison of the Clement–Harrison models with new experiments[J]. Journal of Aerosol Science, 2001, 32(12): 1437-1458. doi: 10.1016/S0021-8502(01)00065-9 [6] KANEYASU N, OHASHI H, SUZUKI F, et al. Sulfate aerosol as a potential transport medium of radiocesium from the Fukushima nuclear accident[J]. Environmental Science & Technology, 2012, 46(11): 5720-5726. [7] SEINFELD J H, PANDIS S N. Atmospheric chemistry and physics: from air pollution to climate change[M]. 2nd ed. Hoboken: John Wiley and Sons, 2006: 88-90. [8] KIM Y H, YIACOUMI S, LEE I, et al. Influence of radioactivity on surface charging and aggregation kinetics of particles in the atmosphere[J]. Environmental Science & Technology, 2014, 48(1): 182-189. [9] REED L D, JORDAN H, GIESEKE J A. Charging of radioactive aerosols[J]. Journal of Aerosol Science, 1977, 8(6): 457-463. doi: 10.1016/0021-8502(77)90038-6 [10] YEH H C, NEWTON G J, RAABE O G, et al. Self-charging of 198Au-labeled monodisperse gold aerosols studied with a miniature electrical mobility spectrometer[J]. Journal of Aerosol Science, 1976, 7(3): 245-253. doi: 10.1016/0021-8502(76)90039-2 [11] 孙晓晖,孙婧,王辉,等. 事故工况下核电厂安全壳内放射性气溶胶电荷分布研究[J]. 原子能科学技术,2022, 56(S1): 67-73. [12] KIM Y H, YIACOUMI S, NENES A, et al. Incorporating radioactive decay into charging and coagulation of multicomponent radioactive aerosols[J]. Journal of Aerosol Science, 2017, 114: 283-300. doi: 10.1016/j.jaerosci.2017.09.024 [13] ADACHI K, KAJINO M, ZAIZEN Y, et al. Emission of spherical cesium-bearing particles from an early stage of the Fukushima nuclear accident[J]. Scientific Reports, 2013, 3(1): 2554. doi: 10.1038/srep02554 [14] KRISTIANSEN N I, STOHL A, OLIVIÉ D J L, et al. Evaluation of observed and modelled aerosol lifetimes using radioactive tracers of opportunity and an ensemble of 19 global models[J]. Atmospheric Chemistry and Physics, 2016, 16(5): 3525-3561. doi: 10.5194/acp-16-3525-2016 [15] VASILAKOS P, KIM Y Η, PIERCE J R, et al. Studying the impact of radioactive charging on the microphysical evolution and transport of radioactive aerosols with the TOMAS-RC v1 framework[J]. Journal of Environmental Radioactivity, 2018, 192: 150-159. doi: 10.1016/j.jenvrad.2018.06.014 [16] 陈志. 电离辐射防护基础[M]. 北京: 清华大学出版社,2020: 10-20, 67-70. [17] KIM Y H, YIACOUMI S, NENES A, et al. Charging and coagulation of radioactive and nonradioactive particles in the atmosphere[J]. Atmospheric Chemistry and Physics, 2016, 16(5): 3449-3462. doi: 10.5194/acp-16-3449-2016 [18] CLEMENT C F, CLEMENT R A, HARRISON R G. Charge distributions and coagulation of radioactive aerosols[J]. Journal of Aerosol Science, 1995, 26(8): 1207-1225. doi: 10.1016/0021-8502(95)00525-0 [19] GUNN R. Diffusion charging of atmospheric droplets by ions, and the resulting combination coefficients[J]. Journal of the Atmospheric Sciences, 1954, 11(5): 339-347. [20] 江帆,黄鹏. Fluent高级应用与实例分析[M]. 北京: 清华大学出版社,2008: 226-258. [21] 徐美芳,苏新彦. 电磁场与电磁波[M]. 西安: 西安电子科技大学出版社,2022: 48-68. [22] LAI A C K, CHEN F Z. Comparison of a new Eulerian model with a modified Lagrangian approach for particle distribution and deposition indoors[J]. Atmospheric Environment, 2007, 41(25): 5249-5256. doi: 10.1016/j.atmosenv.2006.05.088 [23] 葛宝珠,陆芊芊,陈学舜,等. 放射性核素大气扩散数值模拟研究综述[J]. 环境科学学报,2021, 41(5): 1599-1609. [24] 赵宇. 居民区地下车库自然状态下PM1.0颗粒的运动扩散特性研究[D]. 哈尔滨: 哈尔滨工业大学,2016. [25] BALTENSPERGER U, GÄGGELER H W, JOST D T, et al. Chernobyl radioactivity in size-fractionated aerosol[J]. Journal of Aerosol Science, 1987, 18(6): 685-688. doi: 10.1016/0021-8502(87)90097-8 [26] 江帆,黄鹏. Fluent高级应用与实例分析[M]. 北京: 清华大学出版社,2008: 311-316. [27] YEH H C. A theoretical study of electrical discharging of self-charging aerosols[J]. Journal of Aerosol Science, 1976, 7(4): 343-349. doi: 10.1016/0021-8502(76)90088-4 [28] GU W G, HE J P, WANG D Z, et al. The transport and decay of radioactive aerosols in a wall-bounded turbulent flow[J]. Annals of Nuclear Energy, 2019, 134: 125-133. doi: 10.1016/j.anucene.2019.05.023 -
计量
- 文章访问数: 48
- HTML全文浏览量: 21
- PDF下载量: 13
- 被引次数: 0
