Architecture and management of a geological repository - Andra

2 – General Description2.4.1.2 Design, reversibility and flexibility of operationAs a result of the principle of reversibility being taken on board and research being carried out into anindustrially realistic design for an installation intended to be managed on a century time scale, therepository operator is offered adaptive management flexibility.• Modularity of the underground installationsThe modularity of the architecture promotes flexible management of the installations. In particular, itprovides potential for action on the disposal process (construction and operation by phases) and allowsfor the design and method of operation to be changed on the basis of feedback.In this respect, each repository zone can be constructed and operated progressively in successivegroups of cells. It is expected that these groups of structures will be constructed and filled with wastepackages over a period of a few years (generally between two and four years according to theassumptions considered on the throughput of packages).• Durable structures and disposal packagesDue to the principle of reversibility, preference is given to materials and design arrangementspromoting the durability of the structures and the disposal packages.• Waste package emplacement favouring retrievabilityThe waste package disposal facilities and processes are designed with the aim of simplifying anywaste package retrieval operations which may be decided by future generations. Preference is notablygiven to the use of similar means to the ones used for emplacement. As a result, clearances forhandling purposes that can be durably maintained are provided between the packages and/or betweenthe packages and the cell walls. These clearances are minimised, however, with a view to limitinggeomechanical disturbance as indicated above.2.4.1.3 Design, personnel safety and operational safetyOperational safety considerations aim to offer the repository operator a safe strategy and techniquesfor the implementation of activities relating to construction, the transfer of waste packages to theirdisposal cell and the closure of the underground installations.They form an important data component in the design of the access drifts. They also govern the designof equipment and processes for transferring and emplacing the packages in the cells.• Coactivity managementThe possibility of constructing further repository modules while the site is in operation leads to anuclear type activity (operation) being carried out simultaneously with a civil engineering type activity(construction). To avoid interference between these two activities characterised by the throughput ofmaterials and different types of risks, specific drifts per type of activity are opted for in the design. Byspecialising the drifts, transfers of vehicles, people and materials and ventilation flows can beseparated. Similarly, by arranging the repository zones into successive cell subassemblies, it ispossible to conduct just a single activity at any given time within each subassembly.• Standardised disposal packagesThe design of the disposal packages is aimed at facilitating their management and, in particular, atstandardising their handling operations by eliminating the wide diversity in the primary packages thatthey contain, particularly in the case of B waste. Such standardisation reduces the number of handlingdevices and therefore makes the operating process simpler and safer. This enables the number ofdisposal packages to be placed in the cell to be limited to around two to ten per day, all categories ofwaste combined, according to the scenarios and assumptions regarding primary package throughput.DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM58/495