Sweeping heat flux loads on divertor targets: Thermal benefits and structural impacts

• Parametric simulations were performed to study the impact of strike-point sweeping.
• Temperature and heat flux to the coolant can be significantly reduced by sweeping.
• Higher sweeping frequency (0.5–4 Hz) offers advantages for fatigue lifetime.
• Sweeping is suitable for stationary loading if frequency is high enough (e.g. 4 Hz).

One possibility to mitigate the maximum high heat flux (HHF) load on the target is to sweep the position of the strike-point back and forth periodically in order to spread the peak thermal load over a wider width. The aim of this work is to investigate the thermal and structure-mechanical responses of a water-cooled tungsten mono-block target under cyclic HHF loads which are applied in sweeping modes. The study was performed by means of finite element analysis using an ITER-like target geometry. Extensive parametric simulations were carried out for a wide range of HHF loads and for selected sweeping amplitudes and frequencies, respectively. The simulation shows that the maximum temperature and the maximum heat flux to the coolant can be significantly reduced by sweeping. For the parameters studied in this work (0.5–4 Hz, 5–20 cm), higher sweeping frequency or smaller sweeping amplitude offers advantages in terms of fatigue lifetime of interlayer. Sweeping is suitable for the stationary loading if the sweeping frequency is high enough (e.g. 4 Hz) based on the fatigue lifetime prediction of interlayer.