Failure Assessment of Hypervapotron Mockup for Fusion Application with KAERI High Heat Flux Test Facilities

For developing the extreme cooling technology for Plasma Facing Component (PFC), hypervapotron mockup was fabricated and tested using Neutral Beam Injection (NBI) heating system at KAERI. During the test, especially with the JAEA ion source, which has a focused beam and a long pulse, some failures in the mockup with a hypervapotron were experienced. Using the existing correlation for a critical heat flux (CHF), the incident CHF was assessed, in which the modified Tong-75 CHF correlation for the one-sided heat flux was used. The evaluated ICHF is 28.6 MW/m² and is much higher than the loaded peak heat of about 8.7 MW/m² at a 2.3 MW heat load. Therefore, it is difficult that the failure of the mockup was caused by CHF. The thermal lifetimes were evaluated to be about 100 cycles and 11 cycles for 1.56 MW and 2.3 MW heat load conditions, respectively. When the dump heat is reached in the mockup frequently, it can fail in the corner of the inlet region below 11 cycles when a 2.3 MW heat is loaded