Results of the qualification test for ITER blanket first wall small-scale mockups in Korea

Abstract

The ITER first wall (FW) includes beryllium armour tiles joined to a CuCrZr heat sink with stainless steel cooling tubes. The FW panels are one of the critical components in an ITER machine with a surface heat flux of 4.7 MW/m2 or above. The small-scale mockup shall be part of the qualification program and used to validate the performance of the key manufacturing technologies before the production of larger scale components, and this mockup shall utilize the hypervapotron heat sink and manufacturing processes developed for a semi-prototype design. The small-scale mockup includes 48 beryllium armour tiles (12 mm × 12 mm) capable of withstanding the specified heat flux values. The tile thickness shall be 6 mm to minimize the beryllium surface temperature and evaporation under high thermal loads. The detailed fabrication process of semi-prototype small-scale mockups was developed for a qualification test in Korea. For the CuCrZr and stainless steel, the canned materials are processed into an HIP (Hot Isostatic Pressing) device. In the case of beryllium to CuCrZr joining, the HIP was conducted at 580 °C and 100 MPa. For non-destructive tests of the fabricated semi-prototypes, visual and dimension inspections were performed whenever needed during the fabrication process, and ultrasonic tests were performed with ultrasonic probes. Destructive tests for the qualification semi-prototype were performed on a small mockup, which was fabricated together with semi-prototypes. The Korea heat load test facility, KoHLT-EB (Electron Beam) was constructed with an electron gun (Max. 800 kW) for a high heat flux application with a 300 kW high voltage power supply, and maximum accelerating voltage of 60 kV. This test facility was operated to evaluate the performance of these small-scale mockups. A cyclic heat flux test will be performed to evaluate the ITER qualification program.