Observation of spatial distribution of tritium in zirconium alloy with microautoradiography

Spatial distribution of tritium in the oxide layer formed on zirconium allo y was examined by tritium microautoradiography. The zirconium alloy (Zircal oy-2) was oxidized in tritiated steam at 673 K. The autoradiographs of the surface and cross-section of the formed oxide films were observed with a sc anning electron microscope (SEM). They indicated that the concentration of tritium in the zirconium oxide phase was appreciably high at the oxide surf ace and decreased sharply with depth. Inside the oxide him, tritium was con centrated in the intermetallic precipitates such as Zr(Fe,Cr)(2) and Zr-2(F e,Ni). (C) 1999 Elsevier Science B.V. All rights reserved.