Measurement of hydrogen solubility in palladium-silver alloy under intense gamma-ray exposure (13 MR/h)

The influence of intense 60Co gamma-ray irradiation (up to 13 MR/h) on the equilibrium solubility of hydrogen in palladium-silver alloy (80 Pd/20Ag in weight) was investigated by employing a Sieverts type apparatus operated in a hot cave. The alloy contained 0.040 hydrogen in atomic fraction to metal was equilibrated with gaseous hydrogen of 5.7 x 102 Pa (4.3 torr) at 85deg C. Hydrogen pressure rise of 17 Pa (0.13 torr) induced by the irradiation was observed, which corresponded to the dissociation of 0.34 % hydrogen in the solid solution. The pressure increment had a proportional tendency to the gamma-ray intensity. Reversible recovery to the initial equilibrium state was observed within the experimental error after cease of the irradiation. No pressure increase induced by the exposure was detected for the reaction tube without the specimen. This gamma-ray's effect was confirmed not to be caused by hysteresis of concentration-pressure-temperature relation. (author)