Numerical and experimental study of coolant water flow in ITER divertor outer vertical target

ITER divertor outer vertical target (OVT) consists of 22 plasma facing units (PFUs) and 2 stainless support structures (SSSs) including a complex internal structure for coolant water. Pressure drop and flow rate in each PFU are identified as important parameters for acceptable range in terms of the pumping power of cooling water system and performance of heat removal. In this study, computational fluid dynamics (CFD) and a transient reactor analysis code (TRAC-PF1) which is simpler simulation than the CFD have been performed to estimate the pressure drop and flow distribution in 11 PFUs mounted on an OVT SSS (half of the OVT). Results of both prediction methods showed the proper pressure drop and the homogeneous flow distribution within acceptable range of design requirement. To verify these numerical simulations, the results were compared to experimentally measured values in the flow test. This study demonstrated that the TRAC-PF1 as well as the CFD are applicable tools for further optimization of the divertor OVT cooling structure in view of manufacturing.