The most critical step was dowel assembly—not only because the required tolerances for each hole of the upper block, lower block, primary hinge, and the dowels is only 0.02 mm, but also because the surface of dowels is coated with a very thin layer of MoS2 (20±3µm). Because the purpose of the MoS2 coating is to reduce and to sustain the friction coefficient during ITER operation, the coating on the dowels cannot be scratched or otherwise removed, making the precise assembly of the dowels very challenging. In order to increase the confidence in dowel assembly, pre-tests were performed with dummy dowels and a 1:1 scale mockup. Based on the results from these tests, the optimized setting value was fixed and the blocks and the dowels were set on the gravity support assembly jig. After several rounds of 3D measurements to aid in the precise alignment of the blocks, the dowel was successfully assembled.
The successful factory acceptance test opens the way for the first unit to be shipped to ITER and for the series manufacturing of the other eight. Pictured, the team at Haneul Engineering in Korea plus ceremony guests, including the Director-General of ITER Korea, Kijung Jung (blue mask).