Hypervapotron Mockup Experiment and Analysis for Application into the Plasma Facing Components

A hypervapotron mockup was fabricated and used in the 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 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. In addition, using the conventional CFD and FEM codes such as ANASYS-CFX and ANYS-mechanical, the thermal lifetimes were evaluated according to the beam operation and water cooling conditions. 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. The cause of failure seems not to be the CHF considering the existing correlations. 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.