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A Thermodynamic Analysis on the Swelling Stress of Na-Bentonite under Various Solution Conditions

Published online by Cambridge University Press:  20 February 2017

Haruo SATO  and
Masaki FUKAZAWA
Haruo SATO*
Affiliation:
Graduate School of Natural Science and Technology, Okayama University, 3−1−1, Tsushima-naka, Kita-ku, Okayama-shi, Okayama 700-8530, Japan
Masaki FUKAZAWA
Affiliation:
Faculty of Engineering, Okayama University, 3−1−1, Tsushima-naka, Kita-ku, Okayama-shi, Okayama 700-8530, Japan
*
*(Email: [email protected])
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Abstract

The swelling stress of bentonite which is one of the engineered barriers and backfill materials for radioactive waste disposal is strongly dependent on water chemistry such as saline water. The authors have developed a thermodynamic model for calculating the swelling stress (pressure) of bentonite, based on the thermodynamic data of interlayer water in Na-montmorillonite obtained in earlier studies. In this work, the swelling stress of water-saturated Na-bentonite was calculated for various bentonite dry densities and solution conditions such as sodium chloride concentration and nitrate concentration and compared to the measured data.

Swelling stress versus montmorillonite partial density was estimated for solutions containing sodium chloride ([NaCl] = 0−3.4 m, m: molality) and nitrate concentrations ([NaNO3] = 0−6 m) and compared to data measured for bentonites with various montmorillonite contents and silica sand contents. The calculated swelling stresses commonly decreased with increasing [NaCl] and [NaNO3] for the same montmorillonite partial density. The trend of swelling stress versus [NaCl] was in a good agreement with the measured results. The calculated swelling stress versus [NaCl] was also quantitatively in a good agreement within the scattering of the measured data. The trend versus [NaNO3] was also similar to that versus [NaCl]. However, the calculated results were quantitatively different from the measured data ([NaNO3] = 3, 5 m, montmorillonite partial density = 0.76−0.87 Mg/m3). Even though those measurements were conducted under the condition of high ionic strength, the measured data of swelling stresses were almost the same as in the condition of distilled water. Since the measurement periods were quite rather short, it is conceivable that the measurements were not done at equilibrium.

Keywords

stress/strain relationshipenvironmentwaste management
Type
Articles
Information
MRS Advances , Volume 1 , Issue 61: Scientific Basis for Nuclear Waste Management XXXIX , 2016 , pp. 4019 - 4025
Copyright
Copyright © Materials Research Society 2017 

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References

REFERENCES

Japan Nucl. Cycle Develop. Inst., JNC Tech. Rep., JNC TN1410 2000-001 (2000).Google Scholar
Japan Nucl. Cycle Develop. Inst. & the Federation of Electric Power Companies, JNC Tech. Rep., JNC TY1400 2000-002 (2000).Google Scholar
Suzuki, H. and Fujita, T., JNC Tech. Rep., JNC TN8410 99–038 (1999).Google Scholar
Kikuchi, H. and Tanai, K., JNC Tech. Rep., JNC TN8430 2004-005 (2004).Google Scholar
Tanaka, Y., Hasegawa, T. and Nakamura, K., Civil Eng. Res. Lab. Rep., Central Res. Inst. of Electric Power Industry No. N07008 (2007).Google Scholar
Sato, H., Phys. and Chem. of the Earth 33, S538−S543 (2008).CrossRefGoogle Scholar
Sato, H., Mater. Res. Soc. Symp. Proc., Vol. 1124, 6 pages (pdf format) (2009).Google Scholar
Sato, H., Proc. of the 4th Japan-Korea Joint Workshop on Radioactive Waste Disposal 2008: Perspective of Sci.. and Eng., May 27−28, 2008, Hakone, Japan, pp.1−17 (2008).Google Scholar
Sato, H., Abstracts of the 47th Ann. Metg. of the Japan Soc.. for Safety Eng., 22, pp.63−66 (2014).Google Scholar
Robinson, R. A. and Stokes, R. H., Electrolyte Solutions, 2nd ed., Butterworths, London (1959).Google Scholar
Nihon-Kagakukai (Chemical Soc. of Japan), Kagaku-Binran, Kisohen II (Handbook of Chem., Basic Version II), 2nd ed. (1975) [in Japanese].Google Scholar
Sato, H., Proc. 15th Int’l Conf. on Nucl. Eng., April 22−26, 2007, Nagoya, Japan, Paper No.: ICONE15-10207, 7 pages (CD-ROM) (2007).Google Scholar
Sato, H. and Miyamato, S., Appl. Clay Sci., 26, pp.47−55 (2004).Google Scholar
Torikai, Y., Sato, S., and Ohashi, H., Nucl. Technol., 115, pp.73−80 (1996).Google Scholar
Suzuki, H., Fujita, T., and Kanno, T., PNC Technical Report, PNC TN8410 92–057 (1992).Google Scholar
Japan Atomic Energy Agency, Buffer Material Database, http://bufferdb.jaea.go.jp/, accessed on July 14 (2006).Google Scholar
Iriya, K., Fujii, K. and Kubo, H., JNC Tech. Rep., JNC TJ8400 2003-067 (2004).Google Scholar
Iriya, K. and Kubo, H., JNC Tech. Rep., JNC TJ8400 2005-002 (2004).Google Scholar
Higashihara, T., Shimomura, M., Fujiwara, N., Masuoka, K. and Aoki, T., Japan Soc.. of Civil Eng. 2011 Ann. Metg., pp.47−48 (2011).Google Scholar
Japan Nucl. Cycle Develop. Inst., JNC Tech. Rep., JNC TN1410 2000-004 (2000).Google Scholar