A methodology for thermo-mechanical assessment of in-box LOCA events on fusion blankets and its application to EU DEMO HCPB breeding blanket

Within the framework of EUROfusion research activities, the Karlsruhe Institute of Technology (KIT) is developing the Helium Cooled Pebble Bed (HCPB) breeding blanket (BB) for European demonstration fusion power plant (DEMO), with the support of BME and Wigner-RCP (Hungary) and CIEMAT (Spain). During the development of the BB concept in the past years, the in-box Loss Of Coolant Accident (LOCA) has been identified as a main design driver for BB. During this event, a leakage of pressurized coolant within the blanket box happens (in-box LOCA), pressurizing the blanket module and endangering its structural integrity. This accident has not been investigated in a detailed approach yet. In this paper, a more precise methodology is introduced taking into account the temperature evolution of the structure for assessing the structural integrity of BB under in-box LOCA and has been applied to the HCPB BB. The methodology and results are presented and critically discussed.

Thermo-mechanical analysis of ITER first mirrors and its use for the ITER equatorial visible∕infrared wide angle viewing system optical design

ITER first mirrors (FMs), as the first components of most ITER optical diagnostics, will be exposed to high plasma radiation flux and neutron load. To reduce the FMs heating and optical surface deformation induced during ITER operation, the use of relevant materials and cooling system are foreseen. The calculations led on different materials and FMs designs and geometries (100 mm and 200 mm) show that the use of CuCrZr and TZM, and a complex integrated cooling system can limit efficiently the FMs heating and reduce their optical surface deformation under plasma radiation flux and neutron load. These investigations were used to evaluate, for the ITER equatorial port visible∕infrared wide angle viewing system, the impact of the FMs properties change during operation on the instrument main optical performances. The results obtained are presented and discussed.