Development of plasma facing components for fusion experimental reactors

The divertor structure and fabrication process have been investigated, including the structures of the divertor elements and support, fundamental brazing techniques, brazing of large divertor tiles and fabrication method of large divertor modules. Using direct brazing, a partial divertor module with large CFC tiles was fabricated and tested. It was shown that the model had sufficient structural integrity against thermal shocks of ~17 MW/m²×4 sec for up to 1600 times. A fabrication technique for large and complex-shaped divertor module has been developed and successfully applied to a 1 m-long linear and 0.8 m-long curved divertor modules. In addition, preliminary investigation of direct brazing of beryllium to the copper substrate has been conducted. It was found that the bending strength of the bonded materials was around 40 MPa. Furthermore, boron coating on the CFC and Mo has been examined. Using the boron ion implantation technique, boron ions were implanted to the CFC and Mo plates prior to the boron atoms deposition. The samples fabricated with this method were found to have a sufficient thermal shock resistance