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Numerical analysis of heat dissipation through granite and clay in the multi-barrier system of a geological disposal facility


Affiliations
1 Homi Bhabha National Institute, Mumbai 400 094, India
2 Indian Institute of Technology (BHU), Varanasi 221 005, India
3 Indian Institute of Technology Bombay, Mumbai 400 076, India
 

High-level heat-emitting long-lived vitrified radio­active waste produced during recycling of the spent nuclear fuel is under consideration for permanent disposal in deep geological formations with appropriate thermomechanical, hydrogeological and geochemical properties. The capability of these rock formations ensuring long-term confinement and isolation of such waste from the environment is significantly controlled by their efficiency in smoothly dissipating the heat emanating from the waste. A number of rock types such as basalt, granite, clay stones, volcanic tuff, argillites, etc. are being evaluated worldwide as well as in India. In this study, a granite from Jalore and bentonite from Barmer, both from Rajasthan, India, have been evaluated for their heat dissipation capacity. The study revealed that the temperature within granite at the centre of the canister reached 55.21°C, resulting in a thermal stress of 25.50 MPa. Bentonite experienced a temperature of 67.42°C in the central part with maximum thermal stress and displacement of 1.78 MPa and 0.446 mm respectively. A displacement of 0.997 mm was recorded at the granite–bentonite interface. Thus, no significant microcrack formation or undesirable displacement was observed within the granite as well as in bentonite, suggesting their capability to isolate and confine the heat-emitting source for extended periods.

Keywords

Bentonite, deep geological repository, granite, radioactive waste, thermo-mechanical analysis.
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  • Verma, A. K., Gautam, P., Singh, T. N. and Bajpai, R. K., Discrete element modelling of conceptual deep geological repository for high-level nuclear waste disposal. Arab. J. Geosci., 2015, 8, 8027–8038.

  • Raj, K., Prasad, K. K. and Bansal, N. K., Radioactive waste management practices in India. Nucl. Eng. Des., 2006, 236(7–8), 914– 930.

  • Börgesson, L. and Jan, H., Hydraulic bentonite/rock interaction in FEBEX experiment. In Advances in Understanding Engineered Clay Barriers, Proceedings of the International Symposium on Large Scale Field Tests in Granite, 2005, pp. 353–372.

  • Liu, Y. M. et al., Design and validation of the THMC Chinamock-up test on buffer material for HLW disposal. J. Rock Mech. Geotech. Eng., 2014, 6(2), 119–125.

  • Harris, A. F., McDermott, C. I., Bond, A., Thatcher, K. and Norris, S., A non-linear elastic approach to modelling the hydro-mechanical behaviour of the SEALEX experiments on compacted MX-80 bentonite. Environ. Earth Sci., 2016, 75, 1445.

  • Zhao, H. G., Shao, H., Kunz, H., Su, R. and Liu, Y. M., Numerical analysis of thermal process in the near field around vertical disposal of high-level radioactive waste. J. Rock Mech. Geotech. Eng., 2014, 6(1), 55–60.

  • Yang, S. Y. and Yeh, H. D., Modelling transient heat transfer in nuclear waste repositories. J. Hazard. Mater., 2009, 169, 108–112.

  • http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/28/076/28076961 (accessed on 21 April 2021).

  • Ali, S. D. and Kim, J., A numerical simulation of thermo-mechanical behavior of the intact rock in response to the borehole heater test. Ann. Nucl. Energy, 2017, 101, 301–311.

  • Guo, R., Thermohydromechanical modelling of the buffer/container experiment. Eng. Geol., 2011, 122, 303–315.

  • Dixon, D., Chandler, N., Graham, J. and Gray, M. N., Two largescale sealing tests conducted at atomic energy of Canada’s underground research laboratory: the buffer–container experiment and the isothermal test. Can. Geotech. J., 2002, 39, 503–518A.

  • Gens, M. S., Guimarães, L., Alonso, E. E., Lloret, A., Olivella, S., Villar, M. V. and Huertas, F., A full scale in situ heating test for high level nuclear waste disposal. Observations, analysis and interpretation. Géotechnique, 2009, 59, 377–399.

  • Sonnenthal, E., Ito, A., Spycher, N. and Kawakami, S., Approaches to modelling coupled thermal, hydrological, and chemical processes in the drift scale heater test at Yucca Mountain. Int. J. Rock

  • Mech. Min. Sci., 2005, 698–719.

  • Rao, S. M., Kachroo, T. A., Allam, M. M., Joshi, M. R. and Acharya, A., Geotechnical characterization of some Indian bentonites for their use as buffer material in geological repository. In Proceedings of 12th International Conference of International Association for Computer Methods and Advances in Geomechanics, 2008, pp. 2106–2114.

  • Gautam, P. K., Verma, A. K., Sharma, P. and Singh, T. N., Evolution of thermal damage threshold of Jalore granite. Rock Mech. Rock Eng., 2018, 51, 2949–2956.


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  • Numerical analysis of heat dissipation through granite and clay in the multi-barrier system of a geological disposal facility

Abstract Views: 272  |  PDF Views: 120

Authors

Binu Kumar
Homi Bhabha National Institute, Mumbai 400 094, India
A. K. Verma
Indian Institute of Technology (BHU), Varanasi 221 005, India
R. K. Bajpai
Homi Bhabha National Institute, Mumbai 400 094, India
T. N. Singh
Indian Institute of Technology Bombay, Mumbai 400 076, India

Abstract


High-level heat-emitting long-lived vitrified radio­active waste produced during recycling of the spent nuclear fuel is under consideration for permanent disposal in deep geological formations with appropriate thermomechanical, hydrogeological and geochemical properties. The capability of these rock formations ensuring long-term confinement and isolation of such waste from the environment is significantly controlled by their efficiency in smoothly dissipating the heat emanating from the waste. A number of rock types such as basalt, granite, clay stones, volcanic tuff, argillites, etc. are being evaluated worldwide as well as in India. In this study, a granite from Jalore and bentonite from Barmer, both from Rajasthan, India, have been evaluated for their heat dissipation capacity. The study revealed that the temperature within granite at the centre of the canister reached 55.21°C, resulting in a thermal stress of 25.50 MPa. Bentonite experienced a temperature of 67.42°C in the central part with maximum thermal stress and displacement of 1.78 MPa and 0.446 mm respectively. A displacement of 0.997 mm was recorded at the granite–bentonite interface. Thus, no significant microcrack formation or undesirable displacement was observed within the granite as well as in bentonite, suggesting their capability to isolate and confine the heat-emitting source for extended periods.

Keywords


Bentonite, deep geological repository, granite, radioactive waste, thermo-mechanical analysis.

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DOI: https://doi.org/10.18520/cs%2Fv122%2Fi9%2F1089-1093