Tome Architecture and management of a geological repository - Andra

6 – C waste repository zoneThe sleeve, a set of tubes screwed together, is put in position either gradually as the engineered barrierconstruction advances to help guiding the rings, or once the engineered barrier column has been fullyformed.A mobile device is inserted to close and protect the disposal head outside disposal boreholeintervention periods. This device is designed and dimensioned so that handling equipment can passfreely into the handling drifts.6.6.4 Operation of a disposal cell as part of the reversibility approachThe waste package emplacement-retrieval equipment and process using a biological protection caskand concerning vertical disposal borehole can be transposed using industrial feedback fromCOGEMA’s La Hague centre. COGEMA uses a cask comprising a barrel that handles several primarypackages of vitrified waste (CSD-V) in succession in a nine-package capacity storage pit.The similarity between the operations in the storage pit operations at La Hague and those planned forthe disposal boreholes (package emplacement and retrieval) makes a compelling case for adopting asimilar approach in the granite formation [51].The cask illustrated in Figure 6.6.5 is made up of a cylindrical shielded vessel. The walls, made from asteel composite and neutron absorbing material, are about 300 mm thick, to provide radiologicalprotection of the operator.Figure 6.6.5Radiological protection cask for C waste packagesCask loading and unloading is carried out through a cylindrical opening on the underside of the vessel.Inside the vessel, the barrel is made up of a rotary table with three slots and an opening. By revolvingthe table the openings can be lined up to lower the disposal packages freely. Right above the caskopening, the cask is equipped with a winch that enables an integrated clamping arm to pick up apackage and transfer it from the cask to the borehole.The cask dimensions are roughly 2.5 m in diameter by 3.4 m high. The loaded mass will be about 50tonnes. The cask can transport two upright disposal packages and also a radiological protection plugand/or engineered barrier plugs.The disposal package emplacement cycle consists of loading the cask in the surface installations,transferring it to the disposal cell, emplacing the package in the cell and finally returning the cask tothe surface.Dossier 2005 granite - ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL REPOSITORY186/228