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The goal of the eddy current flow meter (ECFM) is to monitor velocities and temperatures of conductive liquid metals. The ECFM can also detect voids in two-phase liquid metal flows. Measurement of these flows can greatly improve the accuracy of the empirical formulas used for fluid dynamics near the reactor core and aid in mapping any non-uniformities in fluid flow such as estimates of temperature and phase. While the eventual goal is to develop the ECFM for the liquid sodium surrounding the Versatile Test Reactor (VTR) core, this report focuses on modeling and experimental validation of ECFM for a moving solid test rod and for liquid mercury in the Target Test Facility (TTF) flow loop to better understand and further develop ECFM measurement capabilities by validating model predictions with benchmark experiments. Eventually the models could be used to design and optimize future ECFMs for specific applications such as monitoring flow within the VTR pool.

Pulsed-laser ablation has been used to grow epitaxial films of Bi2Sr2CaCu2O8−x (Bi-2212) and Bi2Sr2CuO6−x (Bi-2201) on (001) MgO with entirely in situ processing. The films’ layer-stacking sequence, microstructure, and superconducting Tc are highly sensitive to the growth temperature and deposition rate. Pure Bi-2212 films exist over only a narrow temperature range. Pure Bi-2201 films appear at higher growth temperature, while lower growth temperature enhances the Bi-2223 phase, though it is mixed with Bi-2212. The phase homogeneity, in-plane connections among grains, and superconducting Tc of Bi-2212 grown at a given temperature are greatly improved by reducing the deposition rate. Epitaxial Bi-2212 films grown at 740 °C and 0.5 Hz (∼0.05 nm/s) have Tc0 (R=0)=71 K, with Jc∼8×105 A/cm2 at 50 K and Jc∼5×106 A/cm2 at 4.2 K.