Design status of DEMO blanket primary heat transfer system

The design requirements for the DEMO Blanket Primary Heat Transfer System, both for the water and helium concepts have been defined. The plasma facing components cooling circuits have to fulfill several requirements dictated by safety and operational criteria. In particular, the Blanket PHTS of a fusion reactor shall transfer the heat load coming from the plasma to the secondary side to allow power removal from the in-vessel components and produce high quality steam to be sent to the power conversion complex. The design solutions should meet the different characteristics of the various blanket concept and the pulsed operation of the reactor. The interactions of high energetic neutrons with the Blanket internals lead to the generation of Activated Corrosion Products, Tritium and Nitrogen radioisotopes. These fusion-specific radiological products shall be safely confined by the PHTS during the various machine states to make as minimum as achievable the radiological doses to the workers, people and environment. The paper will outline the PHTS design requirements as well the preliminary design for both water and helium blanket cooling systems in terms of circuit layout, located inside the tokamak building, size of piping and equipment, thermodynamic efficiency and safety characteristics.