The Helium Cooled Pebble Bed (HCPB) breeding blanket is one of the two driver-blanket candidates for European fusion demonstration power plant (EU DEMO) within framework EUROfusion Consortium. As EU DEMO program going, testing mockups becomes increasingly important. In this article, engineering design a first-ever breeder zone mockup HCPB reported. will be tested in high-pressure, high temperat...