A Compact, Convective Flow NaK Test Loop for Material Exposure Contained in an Argon Atmosphere

The objective of this research project was to construct a compact NaK loop to test weld configurations for application in a space reactor. The NaK loop fits inside of standard welding glove-box, and holds 64 weld specimens and a diffusion bonded tube-plate assembly. The NaK loop has a furnace which operates at a 650 degrees Celsius. It contains two independent and by-passable cold traps to maintain low oxygen levels in the NaK. The loop also contains a coil heat exchanger to cool the NaK. The loop operates with purely with convective flow, which is driven by the temperature differential between the furnace and the heat exchanger. Convective flow was confirmed at the furnace temperature of 250 degrees Celsius by monitoring temperature behavior. At the operating temperature of 650 degrees Celsius, a flow velocity of 3 millimeters per second was measured. The flow velocity was measured by tracing an induced heat spike as it moved in the system.