Last shrink fitting operation of the Run 3 LHC beam dump spares

The dump block core is made of several graphite grades assembled following different manufacturing procedures. The six isostatic Sigrafine blocks are shrink-fitted into the vessel (with a nominal interference of 750 𝜇m), whilst the low density sector (made of Sigraflex® sheets) is loose-fitted and sits inside the vessel with the only contact forces due to gravity. The Sigraflex® sheets are held in place by two HLM Sigrafine® plates which are retained longitudinally by two steel locking rings. These details and the pre-stress generated by the shrink-fitting are important in the dynamics of the dump block and are therefore included in the model.