Uncertainty Evaluation of Uranium Content Measurements by Redox Potential Titration Methods

Abstract

Uranium content measurement is very important to nuclear material accounting and product quality control in nuclear bulk facilities. It needs high accuracy and precision. In this work, 3 different measurement steps from 2 analytical standards GB 11841—1989 and ASTM C1267-17, which were uranium content test methods by iron(Ⅱ) reduction followed by chromium(Ⅵ) titration, were discussed by simulated experiments and following uncertainty evaluation. The results show that, the total uncertainties of the 3 steps are all lower than 0.1%, which is the international target value of uranium content measurement by redox potential titration method. The step for 2.3 g sample of GB 11841—1989 is more suitable to sign value measurement in reference material production, because of its lowest uncertainty. In routine testing works, the step for 0.20-0.25 g sample of GB 11841—1989 is better in sample weighting, the step of ASTM C1267-17 is better in titration and potassium dichromate solution preparation.

Keywords

• redox potential titration
• uranium content measurement
• uncertainty evaluation
• nuclear material accounting