Architecture and management of a geological repository - Andra

The monitoring of the seal can be carried out at the location of the two instrumented sections of theaccess drift, near to the interface between the clay core and the concrete retaining plug (Figure10.3.13). The monitoring of the lining continues during this stage. It is complemented by severalmonitoring units integrated into the clay core and the concrete retaining plug.Figure 10.3.13Monitoring procedures for the downstream part of a sealThe monitoring of the concrete retaining plug relies on monitoring equipment similar to thosedescribed for the lining (Figure 10.3.12). The monitoring of the swelling clay is based on themonitoring of the dam cores. It involves the use of groupings of monitoring equipment made up ofseveral fiber optic extensometers, a vibrating wire thermometer, a humidity probe and an interstitialpressure cell.10.3.7.4 The evolution of the module B monitoring system after the drift is closedThe closure of the internal connecting drifts in zone B necessitates the abandonment of wiredtransmission equipment leading out of the cell. If it were decided to pursue some of the measurementsin the control cells, recourse to wireless transmission would be a suitable option. This wirelesstransmission through the sealing structures could be relayed by wired equipment in the backfilledconnecting drifts.The lifetime of wireless transmission equipment is limited by the frequency of measurement, thefrequency of signal transmissions, by the number of sensors connected to the equipment and by thecapacity of the system's batteries. By reducing the frequency and the number of measurements, it isconceivable for the lifetime to be extended to several decades. As an example, the RWMC researchprogramme is aiming at a period of approximately fifty years.10.3.8 Monotoring of C disposal cellsThe observation of C waste disposal cells is essentially focussed on the phenomena which characterisethese structures during the different stages of the repository process, i.e.: the evolution of the thermalfield in and around the cell, the evolution of the mechanical constraints exerted by the geologicalformation on the sleeve and the evolution of the atmosphere in the cell which determines the level ofcorrosion of the metal components.DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM407/495