PERFORMANCE OF MOLYBDENUM WITH UF4 AT HIGH-TEMPERATURES AS A WALL MATERIAL FOR SPACE REACTORS

Thin 99.99 pet purity molybdenum (Mo) foils for use in gas core reacto rs have been tested in both liquid and gaseous uranium tetrafluoride ( UF4) at temperature ranges of 1500 to 2000 K under argon pressures app roaching 600 torr for exposure times of 15 to 75 minutes. Weight chang e measurements have been performed before and after the experiments. S urface and cross-sectional analyses of the samples have been done usin g scanning electron microscopy (SEM), electron microprobe (EMP), and e nergy dispersive spectroscopy (EDS). The Mo container, which was expos ed for nearly 9 hours to both liquid and gas phase UF4, was also exami ned. No reaction or diffusion of uranium or fluorine has been found on the cross sections of the samples under the experimental conditions. These results indicate that molybdenum can be a candidate wall materia l in contact with UF4 as used as a circulating fuel at ultrahigh tempe ratures.