Deuterium retention in tungsten under combined high cycle ELM-like heat loads and steady-state plasma exposure

•The impact on the deuterium retention of simultaneous exposure to laser and plasma has been compared to the impact of sequential exposure and to plasma exposure only.•A significant increase of D retention, more than a factor of 12, has been observed during the simultaneous transient heat loads and plasma exposure.•Only 34% of the retained deuterium in the tungsten specimen is located inside the near-surface layer (d<4µm).•Enhanced blister formation has been observed under combined loading conditions at power densities close to the threshold for damaging. It is shown, that blisters are not mainly responsible for the pronounced increase of the D retention.