Determination of acidity in nitric acid solutions containing Plutonium and/or Uranium at high concentration by electric conductivity measurement

Kitagawa, Osamu; Suzuki, Yoshimasa ; Kurosawa, Akira; Watahiki, Masaru; Hiyama, Toshiaki

Using the correlation between electric conductivity and acidity in solution, we have investigated an analytical method that is able to determine acidity in the nitric acid solution by measuring electric conductivity of sample diluted with distilled water, and correcting the electric conductivity for plutonium(Pu) and uranium(U) using multivariate analysis method. We obtained good results as follows, (1) Acidity in the nitric acid solutions containing Pu and U obtained by this method was good agreement, within 10%, compared with the acidity measured by potentiometric titration method. (2) For plutonium nitrate solution and plutonium-uranium mixed nitrate solution, the repeatability and reproducibility for the measurement of electric conductivity at 25.0C were less than 0.52%, and 1.53% respectively. (3) Impurities such as americium and iron in the solutions did not influence to the measurement of electric conductivity, if total amounts of these impurities were less than 1% compared with those of Pu and U. From the results described above, electric conductivity measuring method has been applying to analysis of acidity in the nitric acid solutions containing Pu and U at high concentration handled in Plutonium Conversion Development Facility. Furthermore, this method can be expected for the application to analysis of acidity in nitric acid solutions containing Pu and U for reprocessing process.