Formulas to correct excess pressure and pressure shift to be used in volume measurement for plutonium nitrate solution

摘要

Excess pressure caused by the bubble and the pressure shift resulting from the air column in a dip-tube pressure measurement are the error sources to be considered for highly accurate density, level, and volume determination of plutonium nitrate solution in a tank. A new approach to estimate the maximum, the minimum, and the average of oscillating excess pressure as a function of tube diameter d, solution density rho, and surface tension CT without including height, curvature, and amplitude of the bubble is proposed. This approach can be applied sigma without reducing the rate of downward airflow that is necessary to prevent contamination. When the estimates were compared with the experimental results in a water-ethanol system within the range 3.6 X 10(-6) less than or equal to sigma/(rho g) less than or equal to 7.4 x 10(-6) (m(2)) and 1.8 less than or equal to d root rho g/sigma less than or equal to 9.6 the mean of the difference was <2 Pa. The estimate for the maximum excess pressure was also compared with the conventional formula, and the difference was <1 Pa. We also proposed an equation to estimate the surface tension of the plutonium nitrate solution. For the pressure shift, a new formula assuming that the air density varies exponentially in the tube is proposed. The measured differential pressure is proportional to the hydrostatic pressure, and the coefficient is nearly independent of the liquid level. These correction factors of excess pressure and pressure shift cart practically be given as constants. References: 17