JEOL and others successfully test 3D-printed tungsten components designed to withstand the harsh environment of a fusion reactor

A joint research team from JEOL, North Carolina State University and Oak Ridge National Laboratory installed a full-scale tungsten tile made with a metal 3D printer on the lower divertor of DIII-D, a US fusion research device, and evaluated its plasma durability over 3 days. The test was conducted 74 times using H-mode discharges, and the tile reportedly received approximately 4 minutes of cumulative plasma exposure. After the test, the 3D-printed tile retained its shape, while melting and spallation were observed at the tip of an adjacent conventional tile. Shape retention does not, however, indicate an overall advantage in heat resistance.

The 3D-printed tile was manufactured using electron beam powder bed fusion, known as EB-PBF. The process is characterised by suppressing crack formation by maintaining the surrounding temperature at approximately 1,400°C or higher. The full-scale tile consisted of 2 matching tiles measuring approximately 136 × 143 mm and 20 mm thick. The tiles were mounted on a copper-alloy base, and their surfaces were finished using wire electrical discharge machining and multi-axis CNC grinding. Numerical data on the material's purity and specific alloy composition have not been disclosed.

In terms of comparison and certification, the test cannot be assessed on the same basis as the 2025 DiMES small-sample test or the certification tests for ITER, as their objectives and conditions differ. DiMES applied a heat flux of approximately 20 MW/m² to a small sample, and only minor surface damage was reported. The ITER certification tests involved 6,000 load cycles on an assembly for the outer vertical target. The significance of the present full-scale test is that it verified plasma exposure using a full-scale tile.