Experimental Validation of the LSS Design Change for Uniform Core Flow

In the previous research, they found that the intact design of the Lower Support Structure Bottom Plate (LSSBP) of the APR+ can induce a negative effect considering the uniformity at the core region. It means that the core flow rates were intense especially near the edge region of the intact LSSBP. Therefore, KAERI proposed the design change of the Lower Support Structure Bottom Plate (LSSBP) to reduce the excessive large flow rate at the core edge region. In this study, an experimental study were carried out to evaluate the effect of the design change of the LSSBP on the core flow distribution, although some test results were already reported in the literature. Same test facility with the previous works, named APR+ Core Flow and Pressure (ACOP) test facility which was constructed with a reduced linear scale of 1/5 referring to an APR+ reactor is used, but the comprehensive experimental test conditions were considered in this study. The tests were performed under three different flow conditions, such as a 4-pump balanced flow, 4-pump unbalanced flow, and 3-pump flow conditions. The same test procedure and conditions were applied to the current study for comparison with the previous test results. For three different test conditions, comprehensive experimental study was carried out to validate the design change of the LSSBP. This study focuses on the core inlet flow rate and outlet pressure distributions for the test conditions, since the distributions can be used as an input data in the safety analysis