Design and PIV Measurements on a Wire-Wrapped 61-Rod Hexagonal Fuel Assembly Experimental Facility

The superior uranium utilization efficiency of fast spectrum reactors relative to thermal spectrum reactors was recognized shortly after commercial reactor development started. The sodium fast reactor design, a type of liquid metal fast breeder reactor, was progressed the furthest during the 1960s and 1970s. However in the late 1970s, 1980s, and early 1990s, the expansion of known uranium reserves, decline in nuclear power demand in the USA, and cancellation of the Integral Fast Reactor program slowed the technology development until recently. With modern computational tools for fluid dynamics, the understanding of exterior and interior subchannel coolant ow behavior can be improved. This improvement will allow existing conservatisms in thermal-hydraulic fuel assembly analysis to be minimized. This will lead to more profitable and safer fuel designs. In the past, thermal-hydraulic experiments were performed on sodium fast reactor fuel assemblies. Unfortunately, the data collected is not suitable for computational fluid dynamics simulation validation due to measurements performed with intrusive probes or poor spatial and temporal resolution. Therefore, a need exists for validation reference data for Reynolds-averaged Navier- Stokes and large-eddy simulation turbulence modeling. Completion of this thesis partially met that demand by designing, procuring, constructing, and collecting PIV shakedown data on an experimental ow loop containing a 61 rod hexagonal fuel assembly with helically wrapped wire spacers. The facility was designed for laser-based optical measurement techniques using the matched index of refraction technique. The experimental setup will provide isothermal high spatial and temporal resolution velocity and pressure data for computational fluid dynamics validation