Safeguards Analytical Laboratory Statistical Analysis of Wet Chemistry Quality Control Data

摘要

This report examines quality control data for wet chemistry measurements made at Safeguards Analytical Laboratory (SAL), Seibersdorf, Austria. The statistical properties were evaluated for three data sets: (1) iron titer measurements, (2) percent bias factors for uranium titrations in the uranium laboratory, and (3) percent bias factors for both uranium and plutonium titrations in the plutonium laboratory. The statistical analysis of the iron titer data examined the effect of dodecane to reduce oxidation and the long-term oxidation rates. The statistical analysis of the bias factor data identified the major variance components and examined the behavior of their quality control charts. The sources of variation of the percent bias factors of uranium titrations were estimated for different (1) solutions of standard reference materials, (2) titrant solutions, (3) days, and (4) replicate measurements. Quality control charts for the percent bias factors for uranium and plutonium titrations were used to identify outlier values, procedural changes, and variance component sources. The identified problems were explained by the recorded notes in laboratory notebooks or by comments of laboratory personnel. The variance component analysis and the quality control charts showed that day-to-day variation of percent bias factors require daily determination of bias correction factors. 12 refs., 17 figs., 11 tabs. (ERA citation 14:020148)