In-Tank Measurement of Solution Density

This paper presents the results of an experiment which established the feasibility of in-tank determination of the density of nuclear process solutions in the field with a precision competitive with the precision claimed for laboratory determinations of the density of samples taken from a tank. The in-tank determination is made by inferring the density from the differential pressure measured between two probes immersed at different heights in the tank. The differential pressure was measured using a null-operated quartz bourdon type electromanometer. The work provided a calibration factor, with a precision (estimate of the relative standard deviation of the mean) of 2.2 parts in 10,000, which can be used to infer density from differential pressure measurements in the particular accountability tank. The technique eliminates one error in the laboratory determination of density and minimizes another. It also can be used to indicate the homogeneity of the tank solution and thus determine when a sample should be taken for determination of the concentration of nuclear material in the solution.