Architecture and management of a geological repository - Andra

A similar wireless transmission technique fromdrift to drift has been successfully tested inÄspö's (Sweden) underground laboratory (Figure10.3.8) by the Japanese agency RWMC(Radioactive Waste Management Funding andResearch Center). It aims to increase the batterylifetime to several decades. Similar technology isalso currently in use for the monitoring ofsettling of the Kansai international airportplatform in Japan, which is located on anartificial island.As shown above, wireless transmissiontechnology is currently the focus of a researchand development programme carried out inpartnership between RWMC and Andra aimingto study the feasibility of such a system in the specific case of constraints arising from waste disposalcells, especially in relation to temperature, radiation and interference with metal parts found in thesestructures.10.3.5.4 Experience feedback regarding the exploitation of measurementsIn respect of the exploitation of measurements, a statistical analysis method initially developed byEDF [100] has become internationally established in the monitoring of dams and nuclear power plants.This method is based on the measurements already obtained to describe the behaviour observed, todetermine the amplitude of reversible variations brought about by known phenomena (such as thermaleffects for example) and to calculate the extent of irreversible change. On the basis of an analysis ofthe past history of the structure, it is possible when taking a new measurement, to identify quickly (andautomatically) whether the structure is evolving in a similar manner to past changes, or whether it hasmodified its behaviour. The establishment of correlations between measured values and the use ofnumerical models allows an assessment of the longer term evolution of structures.This approach is now operational in the dams and nuclear power plant fields, as a considerable amountof long-term experience feedback has been accumulated, and this has allowed a good understanding ofthe behaviour of these structures and has therefore enabled an effective analysis method to bedeveloped.In respect of tunnels, and generally speaking of other types of civil engineering structure,measurement analysis beyond the construction phase is relatively recent, and the diversity ofutilisation of tunnels has very often lead to customised measurement analysis solutions [32]. It is basedupon correlations between measurement and upon the comparison between measurements and thepredictions of numerical models. This comparison enables the models to be refined, then to improvethe prediction of the future evolution of the structures. This process of iterative modelling,observation, comparison and improvement of models, can be pursued throughout the operatinglifetime of structures [105].10.3.6 Observation and surveillance strategyEmissionrDrifts in ÄspöReceptionFigure 10.3.8 Experimental wirelesstransmission devise in the undergroundÄspö laboratoryThis section summarises the strategy considered for the observation and surveillance of a reversiblerepository [87]. The essential elements involved reside in the selection of representative structures tobe instrumented and the anticipation of monitoring requirements throughout the lifetime of thesestructures.DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM399/495