Fusion Science and Technology / Volume 52 / Number 4 / November 2007 / Pages 1002-1006
Technical Paper / Tritium, Safety, and Environment
Deuterium ion implantation and subsequent X-ray Photoelectron Spectroscopy (XPS) and Thermal Desorption Spectroscopy (TDS) experiments were performed with varying implantation temperatures to reveal chemical behavior of tritium produced in Li2TiO3. These experimental results showed that there were four deuterium trapping states; two of which were interacted with and without oxygen near the surface, and the other two were interacted with E'-center and with oxygen with the formation of O-D bond in the bulk. These trapping states of deuterium in the bulk were almost the same as those of tritium generated in thermal neutron-irradiated Li2TiO3. The total amount of deuterium retention in the bulk was almost constant until O-D bonds formed in the bulk were decomposed, indicating that tritium trapping could proceed under hot atom chemical reactions. It was concluded that E'-center could trap the implanted deuterium more frequently than oxygen with the formation of O-D bonds in the bulk. Annihilations of them due to oxygen recovery could increase the retention of D with the formation of O-D bonds, resulting in the almost constant deuterium retention ratio up to its decomposition temperature of 573 K.