Development of a micro gas chromatograph for the analysis of hydrogen isotope gas mixtures in the fusion fuel cycle

Analysis of hydrogen isotopes is very important in the fuel cycle system of fusion reactors. Gas chromatography with a cryogenic separation column is one of the most extensively used methods for the analysis of hydrogen isotopes. Micro gas chromatograph (micro GC) with a cryogenic column is expected to improve the analysis time, that is a major disadvantage of conventional GC. The present authors have modified the micro GC to use its separation column at cryogenic temperature. In previous work a micro packed column has been tested and indicated fairly good performance. In this work a capillary column was tested at cryogenic temperature for more improvement of analysis time. Obtained retention time of H2, HD and D2 were about 43, 47 and 54 s, respectively, for the column with 0.53 mm of I.D., 4.0 m of length and 0.08 mm of film thickness. Peak resolution between H2 and HD was about 1.12. These results suggest that the column developed in this work attained the practical level for the separation and short analysis time. The estimation of the retention time was carried out using the dispersion model. The retention times of HT, DT and T2 were also estimated using the reduced mass.