Status on the W monoblock type high heat flux target with graded interlayer for application to DEMO divertor

Abstract The divertor is the key in-vessel plasma-facing component being in charge of power exhaust and removal of impurity particles. In DEMO, divertor target must survive an environment of high heat fluxes (∼up to 20 MW/m 2 during transient) and neutron irradiation. This paper presents the first part of the development for the realization of an advanced actively cooled concept aiming at improving the quality of material joining. It is based on the use of a W/Cu functionally graded material (FGM) interlayer instead of the copper interlayer. For this preliminary development, the interlayer (∼25 μm) is made with PVD (Physical Vapor deposition) and composed of continuous gradient of W from 100% at the interior part of the tile to 0% at the external part while Cu varies from 0% to 100%. Hot isotactic pressing is realized to join the CuCrZr tube to W tile equipped with graded material. With infrared thermography (SATIR facility) and US non-destructive examinations, manufactured mock-ups show good interface quality.