Reyes, Denny L (2013-08). Three-Dimensional Velocity Measurement Reconstruction for a Rod Bundle Array using Matched Refractive Index Particle Tracking Velocimetry. Master's Thesis.
In a pressurized water reactor (PWR), pressurized water flows over fuel rods containing radioactive uranium. Potential failure of these nuclear fuel rods is a primary concern, as fuel rod failure typically results in power generation losses and reactor downtime. Thermal parameters such as critical heat flux have traditionally been utilized as performance metrics to ensure that the reactor core remains stable even during failure events. Recently, fuel leaking events have occurred which have resulted in excess debris buildup on fuel rods and fuel grid array mixing devices. Understanding the flow field surrounding these nuclear fuel rods is critical in predicting where crud could deposit. Although CFD simulations have been conducted to characterize the fluid flow around fuel rod bundles, limited experimental data characterizing the mechanics of this fluid flow exists in the current literature.
This study will present experimental data collected detailing the fluid flow around a rod bundle geometry using a novel matched refractive index particle tracking velocimetry (PTV) technique over a 3D volume cross section of a prototypical nuclear fuel rod bundle. Velocimetry tracking will be performed in order to characterize the mechanics of the fluid flow. Using optical distortion mitigation techniques and various image processing methods, data from multiple cameras was used to assemble 3-dimensional velocity information of a turbulent fluid region. Results are compared to the solution of a k-epsilon unsteady RANS numerical simulation.