Laser cutting technology has a characteristic of generating low waste volume, and is expected to be applied to reactor decommissioning. Ejection of molten metal from deep in a kerf has been a challenge for the technique. As a kerf is narrow, an assist gas flow decays with increasing kerf depth. Therefore thermohydraulic interaction between the assist gas and the molten metal plays an important role in kerf formation. In order to quantify the influence of the assist gas flow to the kerf width,

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... evaluated several parameters such as kerf width, working distance and flow rate. Flow field of the assist gas in a mock-up is investigated using PIV. Pressure loss of the assist gas flow decreased with increasing kerf width, and so the assist gas became easier to reach deep in the kerf. This indicated that kerf width is an important parameter in the laser cutting process.