Clays buffers

This experiment is not commonly done because it is difficult to maintain a measurable concentration of the soluble metal at higher pH. It could conceivably pertain to situations in soils where cation exchange on silicate clays buffers the metal ion concentration at the same time that adsorption on variable-charge minerals occurs. It is an unlikely situation that will not be analyzed further. 

Thomas, HR., PJ Cleall, N Chandler, D Dixon and HP. Mitchell, Analysis of the hydraulic interaction between clay buffers and host rock in large scale tests, this volume, 2004. 

Gens, A., Guitnaraes L. do N., Garci a-Molina, A., Alonso, E.E. 2002. Factors controlling rock-clay buffer interaction in a radioactive waste repository. In Engineering Geology. 64 pp. 297-308. 

ANALYSIS OF THE HYDRAULIC INTERACTION BETWEEN CLAY BUFFER AND HOST ROCK IN A LARGE SCALE TEST... 

Abstract This paper examines the hydraulic interaction between emplaced engineered clay buffers and host rock formations. This has been achieved via the analysis of the re-saturation behaviour of a large scale in-situ experiment. Experimental results from a testing programme performed by Atomic Energy of Canada Limited, (AECL), are examined via both direct interpretation of the experimental results and numerical simulations of the test. Analysis of seepage rates into an open borehole indicate the presence of an EDZ prior to the emplacement and some healing of the EDZ after buffer placement. It is also found that correct representation of moisture infiltration into the buffer is essential to capture the variations in pore water pressure in the host rock. 

This paper has examined the hydraulic interaction between emplaced engineered clay buffers and host rock formations. This has been... 

What is the puipose of the clay buffer of a waste repository in granitic rock ... 

Clays, like most other natural substances, have some beneficial and some hazardous impacts on the environment. As described in Part 1, clays have a tendeney to adsorb and immobilize ions. This property enables clays to remove ions of pollutants and contaminants from leachates and waste water, thus reducing pollution and contamination. It also facilitates the use of clays in different pollution control measures like carriers of pesticides, liners in waste disposal etc. Clays can also be used in nuclear waste management clay buffers are built from smectite-rich clays into which the containers of radioactive wastes can be safely disposed (Pusch, 2006). 

Extensive research work has been going on for the safe disposal of radioactive wastes in different parts of the world, especially in the North American and West European countries where fission reactors are aplenty. Different types of clays and cl -derivatives are found to be more effective in safe disposal of different types of radioactive wastes. The clays are easily available than any other buffer materials, and the procedures of waste disposal with clay buffer are less expensive. This encoimages the researchers to explore further possibilities of application of cl s in this field. 

The engineered barriers of a repository (waste form, container, clay buffer and backfill material and repository stmcmre) which will degrade with time due to various physico-chemical processes, strongly affect the geochemistry of fluids and rocks of the near field environment (redox properties, sorption properties, solubility limits, equilibrium chemistry, etc.) and determine the speciation and the subsequent migration behaviour of the radionuclides into the far field. Extensive... 

Saturation and gas migration within clay buffers. Proc. 5th Int. Conf. High-Level Rad. Waste. Manag. Las Vegas. 

PUSCH, R. 1982. Chemical interaction of clay buffer materials and concrete. SKBF/KBS, Report No. SFR 82-01. 

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