Quantitative study of a gaseous atmosphere by Fourier transformation infrared spectroscopy (FTIR)

The aim of this work is to implement an in situ quantitative analysis of gases present in a gaseous atmosphere by Fourier transformation infrared spectroscopy in order to determine the processes occurring during the uranium corrosion reactions. Indeed, during these reactions, the gaseous atmosphere initially present evolves during the reaction and leads to the formation of new gaseous species. The aim is then to in situ quantify the proportion of species present during all the reactional process. A preliminary study on pure gases has been carried out. The studied gases are: CH4, CO2, H2 and CO. The aim is to identify their spectral symbol in the infrared and to determine their behaviour (absorbance) in terms of their concentration. The study of different binary gases mixtures, as for instance CO2/H2, CH4/H2, CO/H2 or CH4/CO2 has been carried out too. This study presents the results concerning the CO2/H2 mixture and more particularly the evolution of the spectral sign of gases in terms of the partial concentrations of H2 and CO2. The study of the spectra of this mixtures show that the presence of a gaseous specie has an influence on the characteristics of the peaks (intensity and area) of the spectra relative to other gaseous species present in the mixture according to a transfer function which has then been determined. The feasibility of the implementation of an in situ quantitative gaseous analysis by Fourier transformation infrared spectroscopy is then discussed from FTIR tables (intensity and area of peaks) obtained on gaseous mixtures. (O.M.)