ITER divertor dome manufacturing development

The divertor dome is the plasma facing component (PFC) located between the two divertor channels. This component must withstand heat loads of 5 MW/m² during nominal operation and transient heat loads of 15 MW/m² for 1-2 sec. The reference design for the prototype dome PFC includes a 15-mm-thick layer of W-brush armor bonded to a 15-mm-thick, formed copper plate with tapered hypervapotron cooling channels. This plate is diffusion-bonded to a copper manifold that distributes coolant to the vapotron channels. The dome PFC is then mechanically attached to a 316L(N)-IG (ITER grade) stainless steel body so that this component can be removed and replaced without displacing other PFCs. Fabrication of this component is challenging since it is made from three different metals with substantially different thermal expansion properties and thermal processing limits. All processing of the CuCrZr must be performed below 550°C to prevent overaging and reduction in mechanical properties