Architecture and management of a geological repository - Andra

9 – Nuclear operating resources in the repositoryThe loaded weight of the C transfer cask is about 41 tonnes for a disposal package of 2 tonnes.The loaded weight of the transfer cask for spent fuels is about 105 tonnes for a disposal package of43 tonnes.9.2.3 The transfer of the packages in the transfer shaftAfter loading a package into a transfer cask, it is then is transferred to the underground installations bythe packages transfer shaft. The process described here is largely the result of a transposition of theindustrial practices used in the mining industry, but also of experience drawn from the operation ofWIPP underground disposal facility (USA) that has been working from 1999.The transfer casks are transferred in the shaft by means of a cage pulled by a cable system. The wholeof the shaft and its associated equipment consists of a space confined by two airlocks: one situated inthe upper part in the surface station and the other situated in the bottom station. During the transfer ofa transfer cask, the airlocks are closed. This space thereby confined is maintained at an underpressure.It communicates by a special drift to the nuclear filtration system which could if necessary be installedat the head of the air exhaust shaft, so as to reduce the possible radiological consequences of a"transfer cask fall in the shaft" type accident (see chapter 11).9.2.3.1 Description of the shaft equipment• Justification of the equipment consideredThe main technically envisageable solutions for lowering the transfer cask whose laden weight canreach 110 tonnes are:- a 10% ramp on which a vehicle travels on pneumatic tyres;- a shaft equipped with a multirope winch system 132 ;- a shaft equipped with a Koepe pulley type friction system.All three principles are possible. However the "Koepe pulley type friction system" solution, illustratedin, is considered at this stage of the studies to be the reference solution, because this system, that hasbeen very widely proven in a mining context for over a century and throughout the world, is a reliabletechnology.The table below gives some reference figures comparable to the present study.132 The mobile hoist reduces the effort exerted by the winchDOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM339/495