AVS 57th International Symposium & Exhibition | |
Actinides and Rare Earths Topical Conference | Monday Sessions |
Session AC+SS-MoM |
Session: | Surface Science of Actinides |
Presenter: | D.L. Pugmire, Los Alamos National Laboratory |
Authors: | D.L. Pugmire, Los Alamos National Laboratory H.G. Garcia Flores, University of Nebraska-Lincoln D.P. Moore, Los Alamos National Laboratory A.L. Broach, Los Alamos National Laboratory P. Roussel, Atomic Weapons Establishment |
Correspondent: | Click to Email |
An area of significant importance to the oxidation of any alloy is the role that the constituent metals play. It has been previously shown that the oxidation rate for the δ-phase stabilized, plutonium/gallium alloy can be significantly affected by the gallium content as well as composition of the oxidizing atmosphere (O2, O2/H2O, H2O). Reasons for the observed rate changes upon alloying with gallium are not understood. A previous study of a variety of δ-plutonium alloys shows that the significant structure difference between unalloyed α-plutonium and alloyed δ-plutonium cannot be the sole cause of different oxidation rates. This implies that the alloying metal must play some role in the slower oxidation rates observed for gallium-stabilized δ-plutonium. In order to elucidate the oxidation mechanism of this commonly employed alloy, it is important to understand the role gallium plays during oxidation. The relatively low concentrations of alloying metals used, typically several atomic percent, can make the activities of gallium during oxidation of δ-plutonium difficult to follow. This complication is compounded by the fact that the initial stages of oxidation are inherently a surface phenomenon, thereby significantly limiting the relative amount of affected material. Significant questions remain as to what is a realistic description for the Pu/Ga-oxide, thin-film system during the initial stages of oxidation.