Abstract: STUDY ON THE SURFACE REACTION OF URANIUM METAL IN HYDROGEN ATMOSPHERE WITH XPSWang Xiaolin Fu Yibei Xie Renshou(Institute of Nuclear Physics and Chemistry of China Academy of Engineering Physics,P.O.Box525 (75),Chengdu 610003)Zuo Changming Zhao Chunpei Chen Hong(The Analytical and Testing Center of Sichuan Union University,Chengdu 610064)ABSTRACTThe surface reactions of uranium metal in hydrogen atmosphere at 25℃ and 200℃ and effects of temperature and carbon monoxide to the hydriding reaction have been studied by Xray photoelectron spectroscopy (XPS).The reaction between H2 and uranium metal at 25℃ leads to the further oxidation of surface layer of metal due to traces of water vapor.At 200℃,it may lead to the hydriding reaction of uranium and the hydriding increases with increasing exposure to H2 in the initial stages.The U4f7/2binding energy of UH3 has been found to be 378.6 eV.Investigation indicates carbon monoxide inhibits both the hydriding reaction and oxidation on the condition of H2CO atmosphere.Key words Uranium Hydrogen(H2) Carbon monoxide(CO) Xray photoelectron spectroscopy (XPS)