Heating requirements for the BARREL toroid coil cryostat of ATLAS in case of vacuum loss

The ATLAS Barrel Toroid cryostat external surface has to be heated by means of heating tapes in order to avoid air condensation in case a major vacuum leak occurs in the coil system. The present note concentrates on the evaluation of the strategies for placing the heating tapes as a basis for calculating their necessary overall length. After a brief description of the ATLAS Barrel Toroid system, the problem is described. A 2D model of a representative portion of the vacuum vessel, on which finite element studies will be performed, is then introduced. The results of the simulations and the conclusions will follow.