Architecture and management of a geological repository - Andra

11 – Operational SafetyFigure 11.6.1Temperature range at the primary packages of bituminised sludge (B2.1) in thecase of a fire in a disposal cell 17911.6.2 ConclusionFire on the handling vehicle used to emplace the packages of bituminised sludge in the disposal cellshould not have any radiological consequences because the concrete envelope of the disposal packageand a thermal shield placed between the fire source and the package effectively protect the primarypackages. On the other hand, the temperature which should be limited to about a hundred degrees isnot of the kind to provoke the spontaneous combustion of the bitumen.11.7 Study of the consequences of a cage fall during the transfer of thedisposal package in a shaftA free fall of the cage from the surface 180 is retained as the accidental scenario of falls in a shaft.Within this context, the studies consist of, first of all, estimating the mechanical consequences of thefall on the various components of the moving body (cage, transfer cask, disposal package, primarypackages) before assessing the radiological consequences of a potentiel loss of containment of thetransfered waste packages and a release of radioactive materials [107].They also include a risk analysis of the criticality [55] which may result from the cage fall during atransfer of spent fuel packages.179 The fire source is placed laterally to the left of the packages and the concrete envelope of the disposal package is not represented.180 The cage fall accidents related to a mechanical failure of the system are extremely rare. In France, the last serious accident knownoccurred at Reumaux (Lorraine) in 1925. It was due to a brake failure which caused a cage fall over approximately 600 m with the last170 m in free fall after the cable broke (it was a drum winch). There was neither an anti-fall system nor a shock absorber in the shaftbottom. 55 miners were killed in this accident, while all of the 28 miners in the upper compartment of the cage were rescued alive.DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM471/495