RD&D-Programme 2004 - SKB

stored so that the material can be used for future reports and safety assessments. Furthermore,
we are devoting particular attention to some long-lived nuclides which have proved to be
important for long-term safety. For some of these we are trying to develop methods to analyze
the content (by means of chemistry and calculations). A system for routine documentation of
the composition, radionuclide content and properties of the waste is being developed at SKB.
Documentation will take place in a similar way as for other LILW.
Research on processes in the repositories is important as preparation for future safety assessments.
Many of the questions that need to be addressed are of a chemical nature and specific
for the high pHs generated by the concrete in the repository and its near-field. The goals of the
planned activities for the period 2005–2010 are as follows:
• Continue the studies of diffusion and sorption of radionuclides in high-pH concrete and rock.
We do not intend to limit ourselves to studying actinides, but will also include activation
products, such as activated molybdenum. An important aspect is the influence of organic
compounds on radionuclide sorption at high pHs, in particular isosaccharinic acid and
cement additives.
• Develop the models for concrete degradation, including the effects of saline water.
• Study the reactions between leachate from concrete and the surrounding gravel in the
repository.
• Field studies and investigations of natural analogues of alkaline concrete environments.
• Corrosion of metals in a concrete environment.
So far we have used roughly the same model as in SR 97 for calculating radionuclide transport
in the near-field, but a model more adapted to LILW would probably have been better. Different
ways to better models will be tried.
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