Modified blanket cooling manifold system for ITER

Abstract

The modular ITER shielding blanket is the innermost part of the reactor directly exposed to the plasma. Its high thermal and nuclear loaded blanket modules (BMs) are water-cooled components. The cooling water is supplied to the BMs by a set of stiff inlet and outlet manifolds mechanically attached to the inner wall of vacuum vessel (VV). The ITER reference design of the blanket cooling manifold (BCM) presents some concerns namely: huge reaction forces at the end supports on the VV, high operating stresses at certain locations on the manifolds the difficulty of localizing possible water leakages and the inability to repair the components remotely in a case of manifold damage. To overcome these problems, a proposal for a new manifold concept has been developed within the European Fusion Development Agreement – Central Support Unit in Garching in the frame of the ITER design review. The original stiff welded structure has been replaced by a bundle of elastic single seamless pipes supplying the cooling water to each module. Based on FEM and CFD calculations the shape and diameter for the pipes were chosen to cope with thermal differential expansion as well as with electro-magnetic (EM) loads and pressure drop requirements. An attachment system was developed to enable precise positioning and fixing of the manifold segments onto the inner wall of the VV. Additionally a remote handling (RH) procedure for the removal and installation sequences was created for the case of manifold damage during operation. This procedure is based on the currently planned RH equipment such as the maintenance cask and the in-vessel transporter (IVT).