THERMAL FATIGUE TESTS WITH ACTIVELY COOLED DIVERTOR MOCK-UPS FOR ITER

Mock-ups for high heat flux components with beryllium and CFC armour m aterials have been tested by means of the electron beam facility JUDIT H. The experiments concerned screening tests to evaluate heat removal efficiency and thermal fatigue tests. CFC monoblocks attached to DS-Cu (Glidcop A125) and CuCrZr tubes by active metal casting and Ti brazin g showed the best thermal fatigue behaviour. They survived more than 1 000 cycles at heat loads up to 25 MW m(-2) without any indication of f ailure. Operational limits are given only by the surface temperature o n the CFC tiles. Most of the beryllium mock-ups were of the flat tile: type. Joining techniques were brazing, hot isostatic pressing (HIP) a nd diffusion bonding. HIPed and diffusion bonded Be/Cu modules have no t yet reached the standards for application in high heat flux componen ts. The limit of this production method is reached for heat loads of a pproximately 5 MW m(-2). Brazing with and without silver seems to be a more robust solution. A flat tile mock-up with CuMnSnCe braze was loa ded at 5.4 MW m(-2) for 1000 cycles without damage. The first test wit h a beryllium monoblock joined to a CuCrZr tube by means of Incusil br azing shows promising results; it survived 1000 cycles at 4.5 MW m(-2) without failure. (C) 1998 Elsevier Science S.A. All rights reserved.