The role of colloids in the transport of radionuclides from a radioactive waste repository: implication on safety assessment
This report describes the results of a project intended to provide data and to develop concepts that would lead to an improvement in the way in which the role of colloids are dealt with in repository safety performance assessment. The results of experimental work based on artificial fracture, column and field systems are described. The interpretation of experimental data using mathematical models is also described. The reversibility of colloid-radionuclide and colloid-surface interactions are key uncertainties. It has been concluded that colloid-mediated transport could become a significant factor for PA for the following reasons: the presence of a large population of colloids or where colloids are generated from degradation of the engineered barrier; where the chemistry of the near field groundwaters (buffered by the engineered barrier system materials) and the natural far field groundwaters are conductive to colloid stability; where radionuclide desorption processes can be shown to be slow relative to the transport rates through the far-field; where colloid uptake onto rock (mineral) surfaces is limited by restricted available surface area and electrostatic repulsion forces between adjacent colloids and where the apertures of the flowing porosity in the rock are sufficiently large to allow colloids to pass without significant physical filtration. The need for further studies is discussed.
Bibliographic Reference: EUR 19781 EN (2001), pp.109. Euro: 19.00
Availability: Available from EUR-OP Sales Agents http://www.eur-op.eu
ISBN: ISBN: 92-894-0816-2
Record Number: 200013316 / Last updated on: 2001-06-25
Original language: en
Available languages: en