The European ITER test blanket modules: Progress in development of fabrication technologies towards standardization

Abstract

The paper reviews progress achieved in development of fabrication technologies and procedures applied for manufacturing of the TBM sub-components, like, HCLL and HCPB cooling plates, HCLL/HCPB stiffening plates, and HCLL/HCPB first wall and side caps. The used technologies are based on fusion and diffusion welding techniques taking into account specificities of the EUROFER97 steel. Development of a standardized procedure complying with professional codes and standards (RCC-MRx), a preliminary fabrication/welding procedure specification (pF/WPS), is described based on fabrication and non-destructive and destructive characterization of feasibility mock-ups (FMU) aimed at assessing the suitability of a fabrication process for fulfilling the design and fabrication specifications. The main FMUs characterization results are reported (e.g. pressure resistance and helium leak tightness tests, mechanical properties and microstructure at the weld joints, geometrical characteristics of the sub-components and internal cooling channels) and the key pF/WPS steps and parameters are outlined. Also, fabrication procedures for the TBM box assembly are presently under development for the establishment of an optimized assembly sequence/scenario and development of standardized welding procedure specifications. In conclusions, further steps towards the pF/WPS qualification are briefly discussed.