Review of groundwater numerical simulation for deep geological disposal of high-level radioactive waste
-
摘要:
开展地下水数值模拟研究是高放废物处置场地安全评价的重要组成部分,然而深地质处置介质类型的复杂性、基岩深部资料的相对匮乏性导致模拟结果存在不确定性,如何刻画深部地下水动力场并评估可能引起的风险已成为高放废物处置安全评价中重点关注的问题。在大量文献调研的基础上,综述了世界典型国家高放废物深地质处置场地的地下水数值模拟与不确定性分析应用,并归纳总结该领域研究经验,得到以下认识:(1)深地质处置场深部构造、裂隙的发育与展布决定了地下水循环条件,探究适用于基岩裂隙地区新的水文地质试验方法是提高地下水数值模型仿真性的基础;(2)不同尺度模型融合是解决深地质处置地下水模拟的有效技术方法,区域尺度多采用等效连续介质法,场地尺度使用等效连续多孔介质和离散裂隙网络耦合模型,处置库尺度使用离散裂隙网络方法,其次需重点关注未来大时间尺度下放射性核素在地质体中的迁移转化规律,模拟预测场址区域地下水环境长期循环演变对核素迁移的潜在影响;(3)考虑到不同的处置层主岩岩性以及在多介质中发生的THMC(温度场—渗流场—应力场—化学场)过程,目前国内外常用的地下水模拟软件有:Porflow、Modflow、GMS及MT3DMS等用于模拟孔隙或等效连续介质,Connectflow、Feflow及FracMan等用于模拟地下水和核素在结晶岩、花岗岩等裂隙中的迁移,TOUGH系列软件主要应用于双重介质的水流、溶质及热运移模拟;(4)指导开展有针对性的模型和参数的不确定性分析工作,减少投入工作量,提高模型精度,并可针对处置库长期演变、废物罐失效、极端降雨等多情景预测模拟,为处置库安全评价及设计提供基础数据支撑;(5)针对我国深地质处置地下水数值模拟研究现状,下一步应加强区域地质、水文地质、裂隙测量以及现场试验等相关的调查及监测工作,多介质耦合、多场耦合模拟及不确定性分析研究将会是未来的研究重点。
Abstract:Groundwater numerical simulation is an important part of the safety assessment for high-level radioactive waste (HLW) disposal sites. The complexity of deep geological disposal media and the relative lack of deep bedrock data lead to uncertainties in the simulation results. How to characterize the deep groundwater dynamic field and evaluate the possible risks has become a key issue in the safety assessment of HLW disposal. Based on a lot of literature investigation, this paper reviews the application cases of groundwater numerical simulation and uncertainty analysis of HLW deep geological disposal sites in typical countries, and summarizes the research experience in this field. The results show that (1) the structure and fracture development and distribution of deep geologic repositories determine the groundwater circulation conditions, and exploration of the new hydrogeological test method suitable for fractured bedrock areas is the basis of improving the accuracy of groundwater numerical simulation. (2) The integration of different scale models is an effective technical method to solve the groundwater simulation for deep geological disposal. The equivalent continuum method is mostly used at a regional scale, the coupling model of equivalent continuous porous medium and discrete fracture network is used at a site scale, and the discrete fracture network method is used at a repository scale. Furthermore, it is necessary to pay more attention to the migration and transformation of radionuclides in geological formations, to simulate and predict the potential impact of the long-term groundwater environment evolution on radionuclide migration in the site area. (3) Considering different host rocks in the disposal layers and the thermal-hydrogeological-mechanical-chemical process occurring in multiple media, the commonly used software for groundwater numerical simulation in HLW deep geological disposal includes Porflow, Modflow, GMS and MT3DMS, which are used to deduct pores or fractures into equivalent continuum, and groundwater flow and nuclides migration in fractures of crystalline rock and granite can be generalized by using Connectflow, Feflow and Fracman, whereas TOUGH series is mainly used to simulate flow, solute and heat transport in dual media. (4) Targeted uncertainty analysis of the models and parameters should be carried out to reasonably reduce workload and improve the model accuracy. Moreover, the prediction simulation of repository long-term evolution, waste canister failure, extreme rainfall and other scenarios can provide basic data support for the safety assessment and design of the repository. (5) In view of the current researches on groundwater numerical simulation of HLW deep geological disposal in China, it is necessary to strengthen the investigation and monitoring of geology, hydrogeology, fissure measurement and field test in the next step, and the multi-medium coupling model, multi-field coupling simulation and uncertainty analysis will be the focus of future researches.
-
表 1 高放废物深地质处置选址及软件使用情况
Table 1. Site selection and simulation software for HLW deep geological disposal
国家 场址 地下实验室 围岩类型 主要用到的模拟软件 中国 新场 北山 花岗岩 Modflow,PMWIN,GoldSim,Phreeqc,EQ3/6,Rockflow,TOUGH系列软件 美国 Yucca Mountain ESF 凝灰岩 Modflow,FEHM,PEST,TOUGH系列软件 瑞典 Forsmark Äspö 花岗岩 Modflow,Darcy Tools,HydroGeoSphere,Connectflow,MIKE 11,MIKE SHE,TOUGH系列软件 法国 Meuse/Haute Marne Bure 黏土岩 Porflow,TOUGH2-MP,Phreeqc,Code-Bright,Comsol Multiphysics 芬兰 Olkiluoto ONKALO 花岗岩 Feflow,Phreeqc,Connectflow,GoldSim,FracMan,HydroGeoSphere -
[1] 杜祥琬. 对我国核能发展战略的几点思考[J]. 中国核电,2012,5(3):194 − 196. [DU Xiangwan. Thought about China’s nuclear power development strategy[J]. China Nuclear Power,2012,5(3):194 − 196. (in Chinese)
[2] LIU H H, DOUGHTY C, BODVARSSON G S. An active fracture model for unsaturated flow and transport in fractured rocks[J]. Water Resources Research,1998,34(10):2633 − 2646. doi: 10.1029/98WR02040
[3] BODVARSSON G S, WU Y S, ZHANG K N. Development of discrete flow paths in unsaturated fractures at Yucca Mountain[J]. Journal of Contaminant Hydrology,2003,62/63:23 − 42. doi: 10.1016/S0169-7722(02)00177-8
[4] HAUKWA C B, WU Y-S, BODVARSSON G S. Modeling thermal-hydrological response of the unsaturated zone at Yucca Mountain, Nevada, to thermal load at a potential repository[J]. Journal of Contaminant Hydrology,2003,62−63:529 − 552. doi: 10.1016/S0169-7722(02)00188-2
[5] ZHANG K, WU Y-S, BODVARSSON G S. Parallel computing simulation of fluid flow in the unsaturated zone of Yucca Mountain, Nevada[J]. Journal of Contaminant Hydrology,2003,62-63:381 − 399. doi: 10.1016/S0169-7722(02)00159-6
[6] YE M, PAN F, WU Y-S, et al. Assessment of radionuclide transport uncertainty in the unsaturated zone of Yucca Mountain[J]. Advances in Water Resources,2007,30(1):118 − 134. doi: 10.1016/j.advwatres.2006.03.005
[7] RECHARD R P, COTTON T A, VOEGELE M D. Site selection and regulatory basis for the Yucca Mountain disposal system for spent nuclear fuel and high-level radioactive waste[J]. Reliability Engineering & System Safety,2014,122:7 − 31.
[8] RECHARD R P. Results from past performance assessments for the Yucca Mountain disposal system for spent nuclear fuel and high-level radioactive waste[J]. Reliability Engineering & System Safety,2014,122(13):207 − 222.
[9] POHLMANN K, HASSAN A, CHAPMAN J. Description of hydrogeologic heterogeneity and evaluation of radionuclide transport at an underground nuclear test[J]. Journal of Contaminant Hydrology,2000,44(3/4):353 − 386.
[10] ARNOLD B W, KUZIO S P, ROBINSON B A. Radionuclide transport simulation and uncertainty analyses with the saturated-zone site-scale model at Yucca Mountain, Nevada[J]. Journal of Contaminant Hydrology,2003,62/63:401 − 419. doi: 10.1016/S0169-7722(02)00158-4
[11] ZYVOLOSKI G, KWICKLIS E, EDDEBBARH A A, et al. The site-scale saturated zone flow model for Yucca Mountain: calibration of different conceptual models and their impact on flow paths[J]. Journal of Contaminant Hydrology,2003,62/63(2):731 − 750.
[12] KELKAR S, DING M, CHU S, et al. Modeling solute transport through saturated zone ground water at 10 km scale: Example from the Yucca Mountain license application[J]. Journal of Contaminant Hydrology,2010,117:7 − 25. doi: 10.1016/j.jconhyd.2010.05.003
[13] KELKAR S, SRINIVASAN G, ROBINSON B A, et al. Breakthrough of contaminant plumes in saturated volcanic rock: implications from the Yucca Mountain site[J]. Geofluids,2013,13(3):273 − 282. doi: 10.1111/gfl.12035
[14] JOYCE S, HARTLEY L, APPLEGATE D, et al. Multi-scale groundwater flow modeling during temperate climate conditions for the safety assessment of the proposed high-level nuclear waste repository site at Forsmark, Sweden[J]. Hydrogeology Journal,2014,22(6):1233 − 1249. doi: 10.1007/s10040-014-1165-6
[15] SELROOS J, FOLLIN S. Overview of hydrogeological safety assessment modeling conducted for the proposed high-level nuclear waste repository site at Forsmark, Sweden[J]. Hydrogeology Journal,2014,22(6):1229 − 1232. doi: 10.1007/s10040-014-1163-8
[16] FOLLIN S, HARTLEY L, RHÉN I, et al. A methodology to constrain the parameters of a hydrogeological discrete fracture network model for sparsely fractured crystalline rock, exemplified by data from the proposed high-level nuclear waste repository site at Forsmark, Sweden[J]. Hydrogeology Journal,2014,22(2):313 − 331. doi: 10.1007/s10040-013-1080-2
[17] CVETKOVIC V, PAINTER S, OUTTERS N, et al. Stochastic simulation of radionuclide migration in discretely fractured rock near the Äspö Hard Rock Laboratory[J]. Water Resources Research,2004,40(2):1 − 16.
[18] WERNER K, BOSSON E, BERGLUND S. Flow and radionuclide transport from rock to surface systems: characterization and modelling of potential repository sites in Sweden[C]//Proceedings of the 11th international conference on environmental remediation and radioactive waste management, September 2−6, 2007. Bruges: Belgium, 2009: 867 − 872.
[19] SCHWARTZ M O. Modelling radionuclide transport in large fractured-media systems: the example of Forsmark, Sweden[J]. Hydrogeology Journal,2012,20(4):673 − 687. doi: 10.1007/s10040-012-0837-3
[20] BOSSON E, SELROOS J O, M STIGSSON, et al. Exchange and pathways of deep and shallow groundwater in different climate and permafrost conditions using the Forsmark site, Sweden, as an example catchment[J]. Hydrogeology Journal,2013,21(1):225 − 237. doi: 10.1007/s10040-012-0906-7
[21] VIDSTRAND P, FOLLIN S, SELROOS J O, et al. Groundwater flow modeling of periods with periglacial and glacial climate conditions for the safety assessment of the proposed high-level nuclear waste repository site at Forsmark, Sweden[J]. Hydrogeology Journal,2014,22(6):1251 − 1267. doi: 10.1007/s10040-014-1164-7
[22] MONTES-H G, FRITZ B, CLEMENT A, et al. Modeling of transport and reaction in an engineered barrier for radioactive waste confinement[J]. Applied Clay Science,2005,29(3/4):155 − 171.
[23] 李露露, 周志超, 邵景力, 等. 高放废物深地质处置地下水流数值模拟方法研究进展[J]. 水文地质工程地质,2021,48(6):13 − 23. [LI Lulu, ZHOU Zhichao, SHAO Jingli, et al. Advances in groundwater numerical simulation in deep geological disposal of high-level radioactive waste[J]. Hydrogeology & Engineering Geology,2021,48(6):13 − 23. (in Chinese with English abstract)
[24] LÖFMAN J. Site scale groundwater flow in Olkiluoto[R]. Helsinki: Posiva Oy, 1999.
[25] KATTILAKOSKI E, KOSKINEN L. Regional-to-site scale groundwater flow in Romuvaara[R]. Helsinki: Posiva Oy, 1999.
[26] LÖFMAN J. Site scale groundwater flow in Olkiluoto- Complementary simulations[R]. Helsinki: Posiva Oy, 2000.
[27] POSIVA O Y. Safety case for the disposal of spent nuclear fuel at Olkiluoto-performance assessment[R]. Eurajoki: Posiva Oy, 2012.
[28] NIEMI A, KOUTIO K, VAITTINEN T, et al. Estimation of block conductivities from hydrologically calibrated fracture networks - description of methodology and application to Romuvaara investigation area[R]. Helsinki: Posiva Oy, 1999.
[29] LANYON G W, MARSCHALL P. Discrete fracture network modelling of a KBS-3H repository at Olkiluoto[R]. Olkiluoto: Posiva Oy, 2006.
[30] POSIVA OY. Olkiluoto site description 2011[R]. Eurajoki: Posiva Oy, 2012.
[31] PULKKANEN V-M, NORDMAN H. Effects of bedrock fractures on radionuclide transport near a vertical deposition hole for spent nuclear fuel[R]. Eurajoki: Posiva Oy, 2011.
[32] POSIVA O Y. Safety case for the disposal of spent nuclear fuel at Olkiluoto - assessment of radionuclide release scenarios for the repository system 2012[R]. Eurajoki: Posiva Oy, 2012.
[33] POTERI A, LAITINEN M. Site-to-canister scale flow and transport in Hästholmen, Kivetty, Olkiluoto and Romuvaara[R]. Helsinki: Posiva Oy, 1999.
[34] BLESSENT D, THERRIEN R, GABLE C W. Large-scale numerical simulation of groundwater flow and solute transport in discretely-fractured crystalline bedrock[J]. Advances in Water Resources,2011,34(12):1539 − 1552. doi: 10.1016/j.advwatres.2011.09.008
[35] OPHORI D U. A simulation of large-scale groundwater flow and travel time in a fractured rock environment for waste disposal purposes[J]. Hydrological Processes,2004,18(9):1579 − 1593. doi: 10.1002/hyp.1407
[36] 王驹, 徐国庆. 中国高放废物深地质处置研究[J]. 水文地质工程地质,1998,25(5):7 − 10. [WANG Ju, XU Guoqing. Study on deep geological disposal of high-level radioactive waste in China[J]. Hydrogeology & Engineering Geology,1998,25(5):7 − 10. (in Chinese)
[37] 苏锐. 低渗透裂隙介质渗透特征评价技术及其应用研究[D]. 北京: 核工业北京地质研究院, 2007
SU Rui. Studies of hydraulic characterization of low-permeable fractured medium and its application[D]. Beijing: Beijing Institute of Geology for Nuclear Industry, 2007. (in Chinese with English abstract)
[38] 董艳辉, 李国敏. 甘肃北山区域地下水随机模拟研究[C]//废物地下处置学术研讨会. 第三届废物地下处置学术研讨会论文集. 北京: 中国岩石力学与工程学会, 2010: 53-58
DONG Yanhui, LI Guomin. Stochastic simulation of regional groundwater flow in Beishan area[C]//Proceedings of the third symposium on underground waste disposal. Beijing: Chinese Society for Rock Mechanics & Engineering, 2010: 53-58. ( in Chinese with English abstract
[39] 王礼恒. 甘肃北山区域-盆地-岩体多尺度地下水数值模拟研究[D]. 北京: 中国科学院大学, 2015
WANG Liheng. Multi-scale groundwater numerical simulation study of regional-basin-site in Gansu Beishan area[D]. Beijing: University of Chinese Academy of Sciences, 2015. (in Chinese with English abstract)
[40] 魏亚强, 董艳辉, 周鹏鹏, 等. 基于离散裂隙网络模型的核素粒子迁移数值模拟研究[J]. 水文地质工程地质,2017,44(1):123 − 130. [WEI Yaqiang, DONG Yanhui, ZHOU Pengpeng, et al. Numerical simulation of radionuclide particle tracking based on discrete fracture network[J]. Hydrogeology & Engineering Geology,2017,44(1):123 − 130. (in Chinese with English abstract)
[41] 尹文杰, 胡立堂, 王景瑞. 基于GRACE重力卫星的甘肃北山地区地下水储量变化规律研究[J]. 水文地质工程地质,2015,42(4):29 − 34. [YIN Wenjie, HU Litang, WANG Jingrui. Changes of groundwater storage variation based on GRACE data at the Beishan area, Gansu Province[J]. Hydrogeology & Engineering Geology,2015,42(4):29 − 34. (in Chinese with English abstract)
[42] CAO X, HU L, WANG J, et al. Radionuclide transport model for risk evaluation of high-level radioactive waste in Northwestern China[J]. Human and Ecological Risk Assessment,2017,23(8):2017 − 2032. doi: 10.1080/10807039.2017.1361811
[43] 曹潇元, 侯德义, 胡立堂. 甘肃北山区域地下水流数值模拟研究[J]. 水文地质工程地质,2020,47(2):9 − 16. [CAO Xiaoyuan, HOU Deyi, HU Litang. Numerical simulation of regional groundwater flow in the Beishan area of Gansu[J]. Hydrogeology & Engineering Geology,2020,47(2):9 − 16. (in Chinese with English abstract)
[44] 肖丰, 王驹, 郭永海, 等. 中国高放废物处置库甘肃北山预选区水文地质研究进展[J]. 铀矿地质,2011,27(3):185 − 192. [XIAO Feng, WANG Ju, GUO Yonghai, et al. Progress of hydrogeological studies in Beishan preselected area of disposal repository for high level radioactive waste in China[J]. Uranium Geology,2011,27(3):185 − 192. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-0658.2011.03.009
[45] 苏锐, 王驹, 陈伟明, 等. 放射性核素在CRP-GEORC地质处置库远场中迁移的灵敏性与不确定性分析[C]//废物地下处置学术研讨会. 第二届废物地下处置学术研讨会论文集. 北京: 中国岩石力学与工程学会, 2008: 327 − 336
SU Rui, WANG Ju, CHEN Weiming, et al. Sensitivity analysis and uncertainty simulation of the migration of radionuclide in the system of geological disposal-CRP-GEORC model[C]//Symposium on underground waste disposal. proceedings of the second conference on underground waste disposal. Beijing: Chinese Society for Rock Mechanics & Engineering, 2008: 327 − 336. (in Chinese with English abstract)
[46] 吴晓东. 高放废物在地质处置中核素迁移数值模拟研究[D]. 抚州: 东华理工大学, 2012
WU Xiaodong. Nuclide transport numerical simulation of high level radioactive waste geological disposal[D]. Fuzhou: East China Institute of Technology, 2012. (in Chinese with English abstract)
[47] 凌辉, 王驹, 陈伟明. 花岗岩天然屏障对放射性核素的阻滞性能模拟研究[J]. 中国科技论文,2017,12(21):2507 − 2511. [LING Hui, WANG Ju, CHEN Weiming. Simulation study on retardation of nuclides by granite geological barriers[J]. China Sciencepaper,2017,12(21):2507 − 2511.
[48] 凌辉, 王驹, 陈伟明. 高放废物地质处置算井子候选场址核素迁移模拟研究[J]. 铀矿地质,2018,34(2):118 − 123. [LING Hui, WANG Ju, CHEN Weiming. Preliminary evaluation of radioactive effect of candidate sites in Suanjingzi sub-area for geological disposal of high-level radioactive waste[J]. Uranium Geology,2018,34(2):118 − 123.
[49] 彭志娟. 高放废物处置库EDZ中核素129I、135Cs的迁移模拟研究[D]. 抚州: 东华理工大学, 2019
PENG Zhijuan. Numerical simulation of 129I & 135Cs nuclide migration in EDZ of the high-level radioactive waste repository[D]. Fuzhou: East China Institute of Technology, 2019. (in Chinese with English abstract)
[50] 李楚. 镅在北山预选处置场研究区的赋存形态及迁移行为探究[D]. 抚州: 东华理工大学, 2019
LI Chu. Study on the occurrence and migration behavior of Am in the research area of Beishan pre-selected disposal site[D]. Fuzhou: East China Institute of Technology, 2019. (in Chinese with English abstract)