Course Description

This course provides the most recent information on the disposal of the most dangerous radioactive waste in countries that make use of nuclear power. The course covers various natural and engineered barriers, including the latest technology, by describing the integral function for judging their importance in isolating possibly released radionuclides from the biosphere. This involves description of the mechanisms that control the transport of radionuclides and the associated impact on the barriers that consist of the waste containers, the clay that embeds the containers, and the host rock.

The waste isolation capacity is the risk and safety in the repository construction and in the long term performance of the barriers and entire repository. Most references on the subject are focused on just one process or function of a single barrier, usually the rock, the present course describes the combined performance of all of them. For decision-makers as well as designers it means that new aspects should be applied in assessing the various types or combinations of barrier components, and consider more realistic scenarios for their function in both short- and long-term perspectives. It means, for instance, that the extremely expensive and comprehensive hydraulic characterization of a large host rock volume is of little value in estimating the groundwater flow pattern in present time and even less valuable for assessing its geohydrological role in a few thousand years from now. This means, in turn, that disposal in very deep bored holes will be competitive because groundwater at great depth is dense and will remain there, and because the now well-developed techniques for borehole sealing guarantees total tightness for any period of time.

The course will also present the use of numerical modelling for long-term safety assessment of repositories. The safety aspects related to contaminant transport will be covered by Prof. Viktor Popov.