THE PERMEABILITY, DIFFUSIVITY AND SOLUBILITY OF DEUTERIUM IN TZM

A gas permeation technique has been employed to study the permeability , diffusivity and solubility of deuterium in the molybdenum alloy, TZM , a potential divertor material for future fusion machines. The measur ements should provide design data useful for the calculation of the re tention and recycling rates of hydrogen isotopes from divertors in ITE R. Measurements were made on disc-shaped samples of 48 mm diameter and 0.1 mm thickness over the temperature range 515-742 K and for driving deuterium pressures in the range 5-50 kPa. It was found that the perm eability varied in the Arrhenius manner and was very similar to that r eported for pure molybdenum. However, the solubility was observed to b e weakly exothermic, which has not been often observed for molybdenum. There was evidence of deuterium trapping affecting the observed diffu sivity and solubility.