Wire electron beam additive manufacturing for monoblock HCPB breeding blanket components: Preliminary assessment through experimental investigation

The Helium-Cooled Pebble Bed (HCPB) Breeding Blanket (BB) is a key driver blanket concept for the EU DEMO fusion power plant, critical to achieving performance and long-term sustainability. However, its current design and fabrication present significant challenges. Conventional fabrication methods provide limited flexibility to meet these requirements. Additive Manufacturing (AM) has emerged as a promising alternative, already well established in the automotive and aerospace industries, but its application in the nuclear industry remains limited. For EU DEMO, several AM approaches have already been investigated for BB subcomponents. However, Wire Electron Beam Additive Manufacturing (WEBAM) remains underexplored despite its potential advantages. The present work provides a preliminary assessment of WEBAM’s suitability for producing Monoblock HCPB BB components, supported by experimental trials for deposition scale effects and post-processing. Grade 92 ferritic-martensitic steel (X10CrWMoVNb9-2, P92) was selected for the experimental trials as a substitute for Eurofer97. In the experimental investigation, WEBAM samples of two different sizes were deposited on P92 substrates to examine the effects of increasing deposition volume on the microstructure, defect characteristics, and mechanical properties, as well as to assess the effectiveness of post-AM heat and hot isostatic pressing (HIP) treatment in mitigating the observed defects. ... mehrMetallographic analyses, hardness measurements, and mechanical testing, including tensile and Charpy impact tests were performed to assess the properties of the AM material relative to those of the base material. Further, challenges associated with scaling and transferability of process and post-processing parameters from Gr.92 Steel to Eurofer97 are discussed in the present work.