FEM and thermal fatigue testing comparison of ITER-like divertor PFUs mock-ups for DEMO

Highlights: • The ITER-like divertor target design consists of applying the ITER design and fabrication technology to DEMO targets. • The optimized geometry was evaluated by means of the structural failure evaluation against the ratchetting and fatigue criteria of the ITER SDC-IC. • The ultrasonic inspection test made before and after the cyclic HHF tests at GLADIS facility confirmed the high quality of fabrication and robust design concept. • The High Heat Flux tests at 20 MW/m² were successfully completed at GLADIS facility with no defects. - Abstract: The divertor is one of the most challenging components for DEMO reactor both from the design and fabrication technology point of view, since it must be capable to withstand the high heat fluxes (HHF) expected during normal operation (up to 10 MW/m²) and slow transient events (up to 20 MW/m²), like loss of plasma detachment. Within the frame of the EUROfusion Consortium the "Target development" subproject inside the Work Package 'Divertor' (WPDIV) has been dedicated to achieve this performance studying different concepts. ENEA focused on the "ITER-like" target that consists of applying the ITER design and fabrication technology to DEMO targets. The ITER-like concept mock-up was at first designed and optimized by FE analysis then manufactured and checked by non-destructive testing (NDT), finally thermal fatigue testing (TFT) and destructive testing (DT) were performed too. This paper reports the comparison of the thermal behavior of the ITER-like mock-ups between the analysis performed using ANSYS-CFX (Computational Fluid Dynamic analysis, CFD) and the outcome of the High Heat Flux tests (HHF) made at GLADIS facility. Finally the mechanical behavior of the mock-ups has been compared in terms of ratchetting applying dedicated criteria of the ITER SDC-IC and the fatigue lifetime has been estimated by means of Low Cycle Fatigue Curves (LCFC).