Thermal performance and 3D analysis of advanced mechanically joined divertor plate for LHD under steady state high heat flux

Thermal performances of an advanced mechanically joined module (MJM) under steady state high heat fluxes of 2.0–4.25 MW/m2 and thermo-mechanical analysis are described. The advanced MJM was designed to apply for a helical divertor plate of a large helical device (LHD) at the next experimental phase II. The advanced MJM has a unified armor/heat sink made of carbon/carbon composite different from the normal MJM with a separated copper heat sink. To evaluate the thermal performance of the advanced MJM, short pulse high heat flux test up to 5.4 MW/m2 and steady state high heat flux tests up to 4.25 MW/m2 have been carried out using a test facility ACT. Moreover, the thermal fatigue test of the advanced MJM up to 150 cycles under steady state high heat flux of 2.5 MW/m2 has been performed. After theses tests, no apparent damage and no cracking on the armor tile were observed although there was a little increase in the armor/heat sink temperature during the thermal fatigue test. To evaluate the thermal stress in the armor/heat sink of the MJM during steady state high heat flux test and to optimize the structure, thermo-mechanical analyses are done using a 3D CAD.