Fabrication feasibility study on copper cold spray in tokamak system

To improve the plasma vertical stabilization during tokamak operation, partial pure copper layer could be considered on the inner shell of vacuum vessel which is large complex component made of stainless steel. The copper cladding has been a great challenge due to the complicated configuration and difficulty of dissimilar metal joining. From an engineering point of view, there are several candidates for the copper cladding such as cold spray, overlay welding and explosive welding. In this paper, fabrication feasibility study for copper cladding has been carried out by using cold spray method, and a set of full scale mock-up of in-vessel component has been conducted to demonstrate applicability of copper cold spray and to verify copper layer. The results of copper cold spray on test specimens and mock-up showed good properties and no defects on the thick copper layer. Optimum conditions of copper cold spray have been developed based on these results. Accordingly, it can be concluded that cold spray is a feasible and practical method to achieve thick copper cladding on tokamak component.