Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
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Swelling and hydraulic characteristics of two grade bentonites under varying conditions for low-level radioactive waste repository design

  • Chih-Chung Chung (Dept. of Civil Engineering/Research Center for Hazard Mitigation and Prevention, National Central University) ;
  • Guo-Liang Ren (Dept. of Civil Engineering, National Central University) ;
  • I-Ting Chen (Dept. of Civil Engineering, National Central University) ;
  • Che-Ju, Cuo (Dept. of Civil Engineering, National Central University) ;
  • Hao-Chun Chang (Nuclear Back-End Project, Sinotech Engineering Consultants)
  • Received : 2023.07.17
  • Accepted : 2023.11.24
  • Published : 2024.04.25
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Abstract

Bentonite is a recommended material for the multiple barriers in the final disposal of low-level radioactive waste (LLW) to prevent groundwater intrusion and nuclear species migration. However, after drying-wetting cycling during the repository construction stage and ion exchange with the concrete barrier in the long-term repository, the bentonite mechanical behaviors, including swelling capacity and hydraulic conductivity, would be further influenced by the groundwater intrusion, resulting in radioactive leakage. To comprehensively examine the factors on the mechanical characteristics of bentonite, this study presented scenarios involving MX-80 and KV-1 bentonites subjected to drying-wetting cycling and accelerated ion migration. The experiments subsequently measured free swelling, swelling pressure, and hydraulic conductivity of bentonites with intrusions of seawater, high pH, and low pH solutions. The results indicated that the solutions caused a reduction in swelling volume and pressure, and an increase in hydraulic conductivity. Specifically, the swelling capability of bentonite with drying-wetting cycling in the seawater decreased significantly by 60%, while hydraulic conductivity increased by more than three times. Therefore, the study suggested minimizing drying-wetting cycling and preventing seawater intrusion, ensuring a long service life of the multiple barriers in the LLW repository.

Keywords

Acknowledgement

This work was supported from Sinotech Engineering Consultants, LTD and Taipower.

References

  1. SKB, International Perspective on Repositories for Low Level Waste, Svensk Karnbranslehantering AB, Sweden, 2010. SKB R-11-16.
  2. IAEA (International Atomic Energy Agency), Characterization of Swelling Clays as Components of the Engineered Barrier System for Geological Repositories, 2013. Vienna.
  3. H.C. Chang, C.Y. Wang, W.H. Huang, The interaction between contacting barrier materials for containment of radioactive wastes, ICAMEST, in: The 2015 International Conference on Advanced Materials and Engineering Structural Technology, 2015. Qingdao, China.
  4. R.C. Ewing, R.A. Whittleston, B.W. Yardley, Geol. Dispos. Nucl. Waste: a primer, Elements 12 (4) (2016) 233-237, https://doi.org/10.2113/gselements.12.4.233.
  5. E. Ballarini, B. Graupner, S. Bauer, Thermal-hydraulic-mechanical behavior of bento- nite and sand-bentonite materials as seal for a nuclear waste repository: numerical simulation of column experiments, Appl. Clay Sci. 135 (2017) 289-299, https://doi.org/10.1016/j.clay.2016.10.007.
  6. C. Chang, S. Borglin, C. Chou, L. Zheng, Y. Wu, T.J. Kneafsey, S. Nakagawa, M. Voltolini, J.T. Birkholzer, Hydro-mechanical behavior of heated bentonite buffer for geologic disposal of high-level radioactive waste: a bench-scale X-ray computed tomography investigation, Appl. Clay Sci. 232 (2023), 106792, https://doi.org/10.1016/j.clay.2016.10.007.
  7. R. Pusch, J. Kasbohm, S. Knutsson, T. Hoang-Minh, L. Nguyen-Thanh, Disposal of low and intermediate-level radioactive waste, J. Earth Sci. Geotech. Eng. 9 (3) (2019) 237-272, https://doi.org/10.1201/9781315205793.
  8. M.S. Bedinger, Geohydrologic Aspects for Siting and Design of Low-Level Radioactive-Waste Disposal, vol. 1034, U.S. Government Printing Office, 1989. U. S. Geological Survey Circular, http://pubs.er.usgs.gov/publication/cir1034.
  9. R. Dohrmann, S. Kaufhold, B. Lundqvist, The role of clays for safe storage of nuclear waste, Develop. Clay Sci. 5 (2013) 677-710, https://doi.org/10.1016/B978-0-08-098259-5.00024-X.
  10. F. Bernachy-Barbe, Homogenization of bentonite upon saturation: density and pressure fields, Appl. Clay Sci. 209 (2021), 106122, https://doi.org/10.1016/j.clay.2021.106122.
  11. M.V. Villar, Thermo-Hydro Mechanical Characteristics and Processes in the Clay Barrier of a High Level Radioactive Waste Repository, State of the Art Report, 2004. Spain.
  12. M. Juvankoski, Buffer Design 2012. POSIVA 2012-14 Report, Posiva Oy, Olkiluoto, 2012.
  13. H. Komine, Simplified evaluation for swelling characteristics of bentonites, Eng. Geol. 71 (2004) 265-279, https://doi.org/10.1016/S0013-7952(03)00140-6.
  14. S.M. Shirazi, H. Kazama, F.A. Salman, F. Othman, S. Akib, Permeability and swelling characteristics of bentonite, Int. J. Phys. Sci. 5 (11) (2010) 1647-1659.
  15. M. Kohno, Y. Nara, M. Kato, T. Nishimura, Effects of clay-mineral type and content on the hydraulic conductivity of bentonite-sand mixtures made of Kunigel bentonite from Japan, Clay Miner. 53 (4) (2018) 721-732.
  16. SKB, Design, Production and Initial State of the Buffer, Svensk Karnbranslehantering AB, Sweden, 2010. SKB Rapport TR-10-15.
  17. T. Sugiyama, Y. Tsuji, Use of a migration technique to study alteration of compacted sand-bentonite mixture in contact with concrete, Phys. Chem. Earth 33 (2008) S276-S284, https://doi.org/10.1016/j.pce.2008.10.057.
  18. H. Wu, L. Hu, Q. Wen, Electro-osmotic enhancement of bentonite with reactive and inert electrodes, Appl. Clay Sci. 111 (2015) 76-82, https://doi.org/10.1016/j.clay.2015.04.006.
  19. L. Zheng, H. Xu, J. Rutqvist, M. Reagan, J.T. Birkholzer, M.V. Villar, A. M. Fernandez, The hydration of bentonite buffer material revealed by modeling analysis of a long-term in situ test, Appl. Clay Sci. 185 (2020), 105360, https://doi.org/10.1016/j.clay.2019.105360.
  20. H.Y. Jo, T. Katsumi, C.H. Benson, T.B. Edil, Hydraulic conductivity and swelling of nonprehydrated GCLs permeated with single-species salt solutions, J. Geotech. Geoenviron. Eng. 127 (7) (2001) 557-567, https://doi.org/10.1061/(ASCE)1090-0241(2001)127:7(557).
  21. D. Savage, S. Benbow, Low pH Cements, SKI Report, Swedish Nuclear Power Inspectorate, Stockholm, Sweden, 2007.
  22. SKB, Safety Analysis for SFR Long-Term Safety, Svensk Karnbranslehantering AB, Sweden, 2014. SKB Rapport TR-14-01(2014).
  23. G. Xiang, W. Ye, Y. Xu, F.E. Jalal, Swelling deformation of Na-bentonite in solutions containing different cations, Eng. Geol. 277 (2020), 105757, https://doi.org/10.1016/j.enggeo.2020.105757.
  24. A.R. Estabragh, A. Soltani, A.A. Javadi, Effect of pore water chemistry on the behaviour of a kaolin-bentonite mixture during drying and wetting cycles, European J. Environ. Civil Eng. 24 (7) (2020) 895-914, https://doi.org/10.1080/19648189.2018.1428691.
  25. H. Wu, L. Hu, G. Zhang, Effects of electro-osmosis on the physical and chemical properties of bentonite, J. Mater. Civ. Eng. 28 (8) (2016), 06016010, https://doi.org/10.1061/(ASCE)MT.1943-5533.000157.
  26. Y. He, W.M. Ye, Y.G. Chen, B. Chen, B. Ye, Y.J. Cui, Influence of pore fluid concentration on water retention properties of compacted GMZ01 bentonite, Appl. Clay Sci. 129 (2016) 131-141, https://doi.org/10.1016/j.clay.2016.05.020.
  27. W.M. Ye, F. Zhang, Y.G. Chen, B. Chen, Y.J. Cui, Influences of salt solutions and salinization-desalinization processes on the volume change of compacted GMZ01 bentonite, Eng. Geol. 222 (2017) 140-145, https://doi.org/10.1016/j.enggeo.2017.04.002.
  28. Taipower Corporation, Survey and Evaluation of Backfill Material for the Final Low-Level Radioactive Waste Disposal Project, Taipower Report, 2015 (in Chinese).
  29. ASTM, Standard Practice for the Preparation of Substitute Ocean Water, 2021, https://doi.org/10.1520/D1141-98R21. ASTM D1141-98.
  30. W.M. Ye, F. Zhang, B. Chen, Y.G. Chen, Q. Wang, Y.J. Cui, Effects of salt solutions on the hydro-mechanical behavior of compacted GMZ01 Bentonite, Environ. Earth Sci. 72 (2014) 2621-2630, https://doi.org/10.1007/s12665-014-3169-x.
  31. Y. He, W.M. Ye, Y.G. Chen, Y.J. Cui, Effects of K+ solutions on swelling behavior of compacted GMZ bentonite, Eng. Geol. 24 (2019) 241-248, https://doi.org/10.1016/j.enggeo.2018.12.020.
  32. ACI Committee 349, Code requirements for nuclear safety-related concrete structures and commentary, ACI CODE-349-13 (2014).
  33. American Colloid Company, Retrieved from, https://www.mineralstech.com/docs/default-source/performance-materials-documents/american-colloid-company/product-solutions/mti_mcst_tds_mx-80.pdf?sfvrsn=beea2df7_2, 2021.
  34. Kunimine Industries Co., LTD, Retrieved from, https://www.kunimine.co.jp/download/pdf/catalog/catalog_kunigel_v1.pdf, 2021.
  35. O.H. Lars, K.A.B. Kemakta, Modelling of Long-Term Concrete Degradation ProcesSes in the Swedish SFR Repository, SKB Rapport TR-01-08, Svensk Karnbranslehantering AB, Sweden, 2001.
  36. A. Hedin, Buffer, Backfill and Closure Process Report for the Safety Assessment SR-Site, Svensk Karnbranslehantering AB, Sweden, 2010. SKB Rapport TR-0-47.
  37. H. Komine, Cation filtration of montmorillonite on hydraulic conductivities of some bentonites in artificial seawater, J. Geotech. Geoenviron. Eng. 147 (5) (2021), 06021002.
  38. E. Gaucher, C. Tournassat, C. Nowak, Modelling the Geochemical Evolution of the Multi-Barrier System of the Silo of the SFR Repository, SKB Rapport R-05-80, Svensk Karnbranslehantering AB, Sweden, 2005.
  39. P. Delage, M.D. Howat, Y.J. Cui, The relationship between suction and swelling properties in a heavily compacted unsaturated clay, Eng. Geol. 50 (1998) 31-48, https://doi.org/10.1016/S0013-7952(97)00083-5.
  40. W.H. Huang, Experimental study on the thermo- and hydro- properties of two bentonites as buffer materials, EGU General Assembly 2020 (2020) 4-8, https://doi.org/10.5194/egusphere-egu2020-19178. May 2020, EGU2020-19178.
  41. L. Nguyen-Tuan, PhD Thesis, Coupled Thermos-Hydro-Mechanical Analysis: Experiment and Back Analysis, Ruhr-Universitat Bochum Germany, 2014, https://doi.org/10.13140/RG.2.2.25274.49607.
  42. S. Yoon, G.Y. Kim, Measuring thermal conductivity and water suction for variably saturated bentonite, Nucl. Eng. Technol. 53 (3) (2021) 1041-1048, https://doi.org/10.1016/j.net.2020.08.017.
  43. ASTM, Standard Test Methods for One-Dimensional Swell or Collapse of Soils, 2021, https://doi.org/10.1520/D4546-21. ASTM D4546-21.
  44. S.A. Taqieddin, A.S. Al-Homoud, A. Awad, S. Ayyash, Geologic problems related to dam sites in Jordan and their solutions, Eng. Geol. 39 (1995) 252-261, https://doi.org/10.1016/0013-7952(95)00013-6.
  45. A.R. Estabragh, A. Soltani, A.A. Javadi, Effect of pore water chemistry on the behaviour of a kaolin-bentonite mixture during drying and wetting cycles, European J. Environ. Civil Eng. 24 (7) (2018) 895-914, https://doi.org/10.1080/19648189.2018.1428691.
  46. IAEA, Characterization of Swelling Clays as Components of the Engineered Barrier System for Geological Repositories, International Atomic Energy Agency, Vienna, 2013.
  47. Z.X. Zeng, Y.J. Cui, F. Zhang, N. Conil, J. Talandier, Investigation of swelling pressure of bentonite/claystone mixture in the full range of bentonite fraction, Appl. Clay Sci. 178 (2019), 105137, https://doi.org/10.1016/j.clay.2019.105137.
  48. W.C. Chen, W.H. Huang, Effect of groundwater chemistry on the swelling behavior of a Ca-bentonite for deep geological repository, Phys. Chem. Earth 65 (2013) 42-49, https://doi.org/10.1016/j.pce.2013.05.012.
  49. E. Castellanos, M.V. Villar, E. Romero, A. Lloret, A. Gens, Chemical impact on the hydro-mechanical behavior of high density FEBEX bentonite, Phys. Chem. Earth 33 (2008) S516-S526, https://doi.org/10.1016/j.pce.2008.10.056.
  50. Y.G. Chen, Y. He, W.M. Ye, C.H. Lin, X.F. Zhang, B. Ye, Removal of chromium (III) from aqueous solutions by adsorption on bentonite from Gaomiaozi, China, Environ. Earth Sci. 67 (5) (2012) 1261-1268, https://doi.org/10.1007/s12665-012-1569-3.
  51. C.M. Zhu, W.M. Ye, Y.G. Chen, B. Chen, Y.J. Cui, Influence of salt solutions on the swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite, Eng. Geol. 166 (2013) 74-80, https://doi.org/10.1016/j.enggeo.2013.09.001.
  52. S. Suzuki, S. Prayongphan, Y. Ichikawa, B.G. Chae, In situ observations of the swelling of bentonite aggregates in NaCl solution, Appl. Clay Sci. 29 (2) (2004) 89-98, https://doi.org/10.1016/j.clay.2004.11.001.
  53. J.S. Shao, D.A. Sun, F. Peng, Z.T. Zeng, Effect of the alkaline solution concentration on swelling performance of MX80 granular bentonite, European J. Environ. Civil Eng. (2023), https://doi.org/10.1080/19648189.2023.2177753.
  54. P.G. Studds, D.I. Stewart, T.W. Cousens, The effects of salt solutions on the properties of bentonite-sand mixtures, Clay Miner. 33 (4) (1998) 651-660, https://doi.org/10.1180/000985598545804.
  55. Y.G. Chen, C.M. Zhu, W.M. Ye, Y.J. Cui, Q. Wang, Swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite under salinization-desalinization cycle conditions, Appl. Clay Sci. 114 (2015) 454-460, https://doi.org/10.1016/j.clay.2015.06.033.
  56. Y.G. Chen, Y.Q. Cai, K. Pan, W.M. Ye, Q. Wang, Influence of dry density and water salinity on the swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite-sand mixtures, Acta Geotechnica 17 (5) (2022) 1879-1896, https://doi.org/10.1007/s11440-021-01305-7.
  57. T.J. Guo, B.M. Chan, Y.W. Chan, Effect of bentonite on buffer backfill material properties in acidic environment, Proceedings of the Annual Meeting of the Taiwan Concrete Institute, December 12-15, 2021: General Session and Parasession on Engineering Materials, Kaohsiung, Taiwan. (in Chinese)..
  58. O. Karnland, S. Olsson, U. Nisson, P. Sellin, Experimentally determined swelling pressure and geochemical interactions of compacted Wyoming bentonite with highly alkaline solutions, Phys. Chem. Earth 32 (2007) 275-286, https://doi.org/10.1016/j.pce.2006.01.012.
  59. H.N. Anh, H. Ahn, H.Y. Jo, G.Y. Kim, Effect of alkaline solutions on bentonite properties, Environ. Earth Sci. 76 (10) (2017) 374-383, https://doi.org/10.1007/s12665-017-6704-8.