Experimental Flow Mixing Effects in the Cold-Leg of a Pressurized Water Reactor for CFD-UQ

Abstract

The main objective of "Experimental Flow Mixing Effects in the Cold-Leg of a Pressurized Water Reactor for CFD-UQ” is to investigate mixing phenomena in the cold leg and of a Pressurized Water Reactor. The experimental facility constructed at Texas A&M collects high fidelity experimental data in a prototypical geometry to test uncertainty quantification methods. The purpose of gathering high-fidelity data is to validate computational fluid dynamic (CFD) codes. Two different test conditions were incorporated for experiment. The “Open Test” utilized two working fluids with a density difference of approximately 100 kg/m^3 . The “Blind Test” utilized two fluids that had a density difference of approximately 200 kg/m^3 . The open test results were produced for the purpose of being shared with the analyst for validation of the CFD model for the experiment. Both Open Test and Blind Test were conducted under isothermal conditions. Particle Image Velocimetry (PIV) and Laser Induced Fluorescence (LIF) methods were used in parallel to capture instantaneous velocity and fluid concentration measurements in an area within the cold leg near the vessel nozzle. PIV techniques were used to capture instantaneous velocity fields in the downcomer, which is the area directly below the nozzle. This data was temporally averaged to conduct a statistical analysis.