Evaluation of tritium release behavior from Li₂TiO₃ during DT neutron irradiation by use of an improved tritium collection method

Highlights: • Behavior of tritium released from Li₂TiO₃ under neutron irradiation was measured. • Tritium collection method with hydrophobic catalyst was demonstrated successfully. • Temperature of Li₂TiO₃ was dominant to control the chemical form of tritium release. - Abstract: The accurate measurement of behavior of bred tritium released from a tritium breeder is indispensable to understand the behavior for a design of a tritium extraction system. The tritium collection method combined a CuO bed and water bubbles was not suitable to measure transient behavior of tritium released from Li₂TiO₃ during neutron irradiation because tritium released behavior was changed to be delayed due to adsorption of oxidized tritium on the CuO. Hence, the tritium collection method with hydrophobic catalyst instead of the CuO was demonstrated and succeeded the accurate release measurement of tritium from Li₂TiO₃. With the method, we assessed the behavior of tritium release under the various conditions since tritium should be released from Li₂TiO₃ as the form of HT as much as possible from the view point of the fuel cycle. Our results indicated; promotion of isotopic exchange reaction on the surface of Li₂TiO₃ by addition of hydrogen in sweep gas is mandatory in order to release tritium smoothly from Li₂TiO₃ irradiated with neutrons; the favorable sweep gas to release as the form of HT was hydrogen added inert gas; and the temperature of Li₂TiO₃ was the dominant parameter to control the chemical form of tritium released from the Li₂TiO₃.