The surface reactions of uranium metal with carbon monoxide at 25 and
200 degrees C have been studied by X-ray photoelectron spectroscopy (X
PS); respectively. Adsorption of carbon monoxide on the surface layer
of uranium metal leads to partial reduction of surface oxide and resul
ts in U4f photoelectron peak shifting to the lower binding energy. The
content of oxygen in the surface oxide is decreased and O1s/O4f ratio
decreases with increasing the exposure of carbon monoxide. The invest
igation indicates the surface layer of uranium metal has resistance to
further oxidation in the atmosphere of carbon monoxide.