Assessment of an ITER-like water-cooled divertor for DEMO

This paper presents main outcomes of activities, performed in the frame of the EFDA task WP12-DAS-02-T02 and whose main objective was to investigate the feasibility and the range of applicability of a water-cooled divertor (WCD) based on technology developed for ITER to DEMO1. That includes the analysis of the power handling limits, the impact of the end-of-life irradiation fluence, as well as the assessment of available material properties. The considered divertor configuration is a water-cooled monoblock divertor which should be suitable for DEMO operation. For this purpose also Copper alloys, with their high thermal conductivities and relative high strengths, have to be considered when high heat flux handling is required but the aspect of n-irradiation cannot be neglected. All these aspects are assessed for two heat sink materials possible candidates: CuCrZr-IG, EUROFER. For these materials the psychical and mechanical properties were investigated considering their behaviour under n-irradiation and focusing the attention on the conceivable DEMO operational window with respect to temperatures and n-irradiation material properties degradation. The work is then concluded with thermo-mechanical studies of appropriate FE models to predict the heat flux performance capability and lifetime of a W mono-block with cooling pipes made of different Cu-alloys and EUROFER.