Tome Architecture and management of a geological repository - Andra

5 – B waste repository zone5.4.1.4 The cell sealThe cell seal comprises a swelling clay core about ten metres long that is mechanically confinedbetween two plain concrete abutments. The seal is constructed in an over-excavated part of the accessdrift.Figure 5.4.3Basic diagram of a B waste cell seal5.4.2 Dimensioning elements of the disposal cellThe elements taken into account for dimensioning the B disposal cell sections relate to:- the possibilities of grouping different types of waste together (standardised disposal packagedimensions and physical and chemical compatibility of the waste);- geo-mechanical aspects (mechanical characteristics of the granite, geometry of the discontinuities,etc.);- thermal aspects (temperatures of the geological medium and thermal conductivity);- technological aspects (package stacking heights, etc.).5.4.2.1 Grouping the reference packagesGrouping several types of different packages together in a single cell is sought to improve repositorycompactness and make repository management more flexible in terms of package supply.However at the current state of knowledge, some groupings of packages need to be avoided:degradation, through low heat release, of packages emplaced together should be limited or prevented,and the impact of complexing species or acids forming during the alteration of the organic mattercontained in some packages should be limited too. The main outcome is avoiding grouping togetherslightly exothermic packages (reference packages B1 and B5) and packages that are sensitive totemperature (reference packages B2). A co-disposal scenario of reference packages in some cells hasbeen drawn up, that both observe the separation constraints of certain reference packages and also theDossier 2005 Granite - ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL REPOSITORY131/228