AMS measurement of I-129, Cl-36 and C-14 in underground waters from Mururoa and Fangataufa atolls

AMS analyses of Cl-36, I-129 and C-14 in underground water have been performed as part of IAEA's assessment of the radiological situation at Mururoa and Fangataufa atolls. The samples consisted of waters from monitoring wells, and from two cavity-chimneys created by underground nuclear tests. The water samples from the monitoring wells contained varying concentrations of radionuclides, with the highest concentrations of radionuclides found in the two test cavity-chimneys. A comparison of the concentrations of radionuclides determined by AMS, Cl-36 and I-129, and with radionuclides determined using conventional methods, H-3, Sr-90 and Cs-137, shows a reasonable correlation. However, some differences in behaviour, mainly attributed to differences in the sorption characteristics of the elements, are discernible. The concentrations of radionuclides in the underground environment were used to validate geosphere transport models.