An approach for the development of a comprehensive data base of time-dependent hydraulic and transport parameters for concrete engineered barriers - 59299

Document available in abstract form only. Full text of publication follows: This paper presents an approach for the development of a comprehensive data base of time-dependent hydraulic and transport parameters for concrete engineered barriers and multi-layer cover of the future Dessel near surface repository. The parameter derivation is based on an extensive literature review, experimental data from studies on cementitious materials specific for the Dessel repository and numerical modelling studies. Best estimate parameter values for assessments are derived; source range and expert range are also determined, together with probability density functions. Emphasis is also given to the up-scaling of laboratory derived parameter values to the repository component scale resulting in large-scale effective parameters. To accommodate different levels of conservatism in the various assessment calculations defined by ONDRAF/NIRAS, several sets of parameter values have been derived based on assumptions that introduce different degrees of conservatism. For pertinent parameters, the time evolution of such properties due to the long-term concrete degradation is also addressed. The implementation of the approach is demonstrated by considering diffusion coefficient as an example. (authors)