Architecture and management of a geological repository - Andra

4 – Waste disposal PackagesFigure 4.2.7Drawing in an extrusion die using a mandrel and a horizontal pressThese two techniques are tried and tested industrial methods used to obtain good metallurgicalproperties in the object produced.4.2.4.2 Manufacture and integration of ceramic sliding runners• Manufacture and performance of ceramic sliding runnersAt this stage, corundum (alumina Al 2 O 3 ), or dopedcorundum (Al 2 O 3 + ZrO 2 , Y 2 O 3 ) appeared to beappropriate materials due to their mechanicalcharacteristics and their insulating property. Workshoptests using a test bench demonstrated greater robustnessof solid ceramic sliding runners compared to ceramicprojected onto a metal base. The sliding runners usedfor these tests are illustrated in Figure 4.2.8: from left toright a solid ceramic sliding runner, a cast ceramicsliding runner and the metal base used as a support forceramic projection.Figure 4.2.8Ceramic sliding runnersThe test bench illustrated by Figure 4.2.9 permitted alternate movements simulating stress on thesliding runners during package pushing operations (loading and application duration). A rated verticalload of 1 metric ton can be applied to a sliding runner (Figure 4.2.10) 46 .46Over-pack design results in it resting on 3 ceramic sliding runners during cell emplacement. This configuration is the most stablerepresentation and therefore the most probable one for the package in the cell, both during the pushing phase (even if it is not always thesame sliding runner supporting the loads), and at rest. In this tripod configuration, maximum static load supported by one of the slidingrunners can be half of total package weight, or about 1 metric ton.DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM141/495