Tome Architecture and management of a geological repository - Andra

7 - Spent fuel repository zoneFigure 7.3.2Spent fuel canister. On the left the CU1 "long" (AFA - 2LE assembly) and onthe right the CU2 (AFA - 2GE assembly).7.3.3 Manufacturing techniquesSKB initiated the feasibility demonstration for the manufacture of canisters with a copper envelope in1994. The main elements of this study were as follows:- manufacturing cylindrical copper envelopes, bases and lids;- welding the base or lid onto the copper cylinder;- manufacturing cast iron insert partitions.7.3.3.1 Manufacture of thick, wide diameter copper tubesWhile manufacturing inserts is based on current, established foundry techniques, SKB concentrated itsstudies from a very early date on the manufacture of copper tubes with no lengthwise weld. It testedthree possible alternatives:- manufacturing tubes by extrusion;- manufacturing tubes by boring & drawing;- manufacturing tubes by forging.A feasibility demonstration was carried out in 2003 by manufacturing 22 weld-free tubes, including 15by extrusion, 5 by boring & drawing and 2 by forging.All these methods result in the production of copper cylinders ready for machining to the desiredfinished dimensions, both internally, externally and at both ends of the cylinder.SKB has also tested the extrusion process presented below in relation to C waste repository packagemanufacturing techniques (chapter 7.3.3).Dossier 2005 granite - ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL REPOSITORY205/228