Study of the behavior of tritiated water vapor in concrete materials

A fusion reactor requires high levels of safety and public acceptability, so safe confinement of tritium is a key issues. In order to understand tritium behavior in the concrete reactor components, sorption and desorption experiments were carried out as a function of the exposure time for sorption and the kind of purge gas for desorption. The samples used were cement paste, mortar and concrete. These samples were exposed to 740-1110 Bq/cm3 of HTO vapor in 1 kPa of H2O vapor at room temperature. Desorption experiments were carried out using N2 purging gas with water vapor by the thermal desorption method. The concrete materials became almost saturated with HTO within about 1-6 months. Though the chemical form of tritium desorbed from the sample was mostly HTO, HT and other compounds were also detected above 673 K.