Current design of the European TBM systems and implications on DEMO breeding blanket

Abstract Europe is committed in developing the design of the two Test Blanket Systems (TBS) based on HCLL (Helium Cooled Lithium Lead) and HCPB (Helium Cooled Pebble Bed) breeding blanket (BB) concepts. The complexity of the TBS design comes not only from the innovative fabrication technologies and materials adopted for Test Blanket Modules (TBM) but also from the requirements and functions that the TBM ancillary systems have to satisfy and implement. Indeed, the main TBM ancillary systems, namely the Helium Cooling System, the Coolant Purification System and Tritium Extraction System, all belonging to the Safety Important Class (SIC), have to implement fundamental functions, like the transport of the surface and volumetric heat from the TBM to the heat sink, the extraction and processing of the tritium generated in the TBM, the confinement of radioactive inventory, the support to the investment protection and safety functions. On top of the full compliance with the ITER safety principles, the design of the TBM systems is focused on providing high operational reliability and availability not to jeopardize ITER program and, at the same time, also a good operational flexibility to make possible the achievement of the main TBM scientific objectives. This paper gives an overview of the design status of the HCLL and HCPB-TBM (ancillary) systems, updated to the conclusion of the conceptual design phase (CDR). The most relevant technologies, the still open points, the main issues related to the integration in ITER and last relevant results from the on-going R&D activities carried out in Europe are presented and discussed. In the last part, different considerations are proposed about the impact of the design and operation of the main HCLL and HCPB-TBM ancillary systems technologies on the design of a DEMO BB.