China's technological achievements on ITER enhanced heat flux first wall in the pre-PA qualification

摘要

The Chinese Domestic Agency (DA) is procuring ITER Enhanced Heat Flux (EHF) First Wall (FW) panels which shall withstand a surface heat load up to 4.7 MW/m(2) during ITER operation. Prior to the implementation of the ITER Procurement Arrangement (PA), several key technologies in manufacturing the EHF FW panel have been qualified. In the pre-PA task, ITER grade CN-G01 high-purity beryllium has been developed; its chemical composition, mechanical properties and grain size satisfy the ITER requirements. The strict quality control in the manufacturing of bimetallic plate was aimed at increasing the reliability the reliability of hypervapotron (HVT) heat sink for the EHF FW fingers, while a design improvement of the HVT cooling channel improved the thermal fatigue performance. Investigation showed that magnetron sputtering Ti/Cu coating on the beryllium files helps in reducing possible defects and results in better quality of Be-Cu hot isostatic press (HIP) bonding interfaces. As a result of such measures, China completed two EHF FW semi-prototypes with one successfully passing the high heat flux test (HHFT) at 4.7 MW/m(2) for 7500 cycles and 5.9 MW/m(2) for 1500 cycles. Neither damage to the semi-prototype nor off-normal surface temperature increase was observed, which brought the semi-prototype qualification campaign to a successfully conclusion.