Promising cooling concepts for enhanced JT-60SA tungsten actively cooled divertor

• Additively manufactured divertor mock-ups featuring innovative hypervapotron cooling channels were produced. • CFD simulations in single-phase flow show promising thermal performance of the proposed developed concepts (hypervapotron diagonal, hypervapotron chevron). • HIP led to 99.6% density and effective closure of internal porosities. • Hypervapotron diagonal and chevron cooling channel designs passed 100 cycles of HHF testing at 15 MW/m 2 in steady state. • Mock-ups withstood up to 20 MW/m 2 for HV Diagonal and 25 MW/m 2 for HV Chevron, both in steady-state regime. To propose enhanced concepts for the JT-60SA tungsten target divertor able to withstand heat loads higher than 20 MW/m 2 , this paper investigates the flat tile design (flat junction between tungsten armour material and heat sink) using additively manufactured CuCrZr heat sinks. Two enhanced hypervapotron cooling channel designs, called in this paper HV Diagonal and HV Chevron, to efficiently cool the heat sink, are investigated. The components are produced via Laser Powder Bed Fusion (LPBF) and post-processed by Hot Isostatic Pressing (HIP) to close the residual pores coming from the additive manufacturing technique and to simulate the diffusion bonding between the heat sink and tungsten. Computational Fluid Dynamics (CFD) analysis shows that HV Chevron and HV Diagonal designs are promising, as they result in lower inner wall temperatures, up to 40 °C lower at an incident heat flux of 7 MW/m 2 , compared to the conventional hypervapotron design, with an increase of pressure drop about 30 %. These findings are supported by High Heat Flux (HHF) tests, where both mock-ups withstood a heat flux of up to 20 MW/m 2 for HV Diagonal and 25 MW/m 2 for HV Chevron, both in steady-state regime. Preliminary results reveal that LPBF CuCrZr requires a water quench thermal treatment to meet the CuCrZr mechanical properties of the ITER specifications. After thermal treatments, the LPBF CuCrZr material reached a relative density of 99.6 %, with all initial pores effectively closed. This paper presents the potential of the combination of CFD simulation and additive manufacturing for plasma-facing components and demonstrates, as a first step, the feasibility of using LPBF combined with the HIP process for the fabrication of plasma-facing components using CuCrZr as heat sink.