Developments and high heat flux tests of divertor components for LHD

Abstract To develop the divertor plates for the large helical device (LHD), several kinds of brazed modules (BM) and mechanical jointed modules (MJM) have been fabricated and their thermal properties evaluated using an electron beam facility. The MJM and BM will be used as divertor plates in low heat flux (≈5 MW m −2 ) and high heat flux (≈10 MW m −2 ) phases, respectively. Results of the high heat flux tests indicate that some types of BMs satisfy the requirements for the divertor plates. For MJM, the efforts to improve the thermal properties are now being made so as to satisfy the divertor plate requirements. To optimize the design and assembly procedures, divertor mockups of the MJM have been fabricated and installed inside a vacuum vessel mock-up of LHD. The developments of these divertor components and the results of the high heat flux tests are reviewed.