In-Line Gas Chromatograph for Analysis of UF6 and/or F2

Abstract

With the view of continuous analysis of UF6 and/or F2 in the fluorination of U for the development of the fluoride volatility process, an in-line gas Chromatograph, made of anti-corrosive materials against the fluorides, has been constructed using two different columns and automatic sampling system. The separation columns used, were optimized for the simulated process gas composition {(N23, O2, F2)/(UF6) = 18, (N2, O2)/(F2) =3.3}, in order to obtain the complete peak separation. The column selected for UF6 analysis is 0.4 cmø Cu tubing of 3 m long packed with 40% of poly-trifluoromonochloro-ethylene oil which is loaded on poly-tetrafluoro- ethylene powder. The column for F2 analysis is the combination of the above column with a conversion column of 0.4 cmø tubing of 2 m long packed with KCl powder. Under these column conditions, the analytical time is 9 and 3 min for UF6 and F2, respectively at the flow rate of 100 ml/min. The calibration curves are linear with a zero intercept, and the analytical limits are, respectively 0.2 and 1 mmHg in partial pressures of UF6 and F2 with 10 ml of sampling volume. In actual adaptation to the fluorination of uranium oxides, the in-line gas Chromatograph was satisfactorily able to measure the reaction rate and to detect the end of fluorination.