Manufacture of primary first wall panel prototypes for the ITER blanket shield modules

Abstract

A Research and Development programme for the ITER shield blanket has been implemented in Europe to provide input for the design and the manufacture of the full-scale production components. It involves in particular the fabrication and testing of mock-ups (small scale and medium scale) and prototypes of shields and primary first wall (PFW) panels. These prototypes aim at demonstrating the fabricability of the components. The PFW panels consist of a bi-metallic structure with a 316L stainless steel (SS) backing plate and a copper (Cu) alloy heat sink layer. There are two Cu alloy candidates: CuCrZr and CuAl25 alloys. Beryllium (Be) tiles are joined to the Cu alloy heat sink as plasma facing material. Two hot isostatic pressing (HIPping) methods are being considered in Europe for the fabrication of the bi-metallic structure of the PFW panels. With solid HIPping, the 316L SS backing plate, the Cu alloy plates and the 316L SS tubes are joined together with one single HIP cycle at 1040/spl deg/C. With powder HIPping, a first HIP cycle at 1100/spl deg/C is used to consolidate the 316L SS powder with embedded 316L SS tubes. A second HIP cycle at 1040/spl deg/C is then performed for consolidating and joining the CuCrZr powder. Beryllium tiles are then joined by HIPping or brazing; high temperature HIPping or furnace brazing for PFW panels with CuAl25 alloy heat sink material, and low temperature HIPping or inductive brazing for PFW panels with CuCrZr alloy heat sink material. Three full-scale panel prototypes have already been completed demonstrating the manufacturing feasibility of ITER PFW panels. Two more are under fabrication. All these panels will be thermal fatigue tested to confirm the good results already obtained with PFW mock-ups. This paper presents the fabrication route used for each panel prototype.