H diffusion constants, D H , have been obtained from steady-state fluxes through Pd membranes with the downstream side maintained at p H 2 ≈ 0. Good linearity of plots of H flux versus (1/d), where d is the thickness, attests to H permeation being bulk diffusion controlled in this temperature (423-523 K) and p H 2 range (≤0.2 MPa). D H values have been determined at constant p up and also at constant H content. H fluxes through Pd membranes with three different surface treatments have been investigated (polished (unoxidized), oxidized and palladized) in order to determine the effects of these pre-treatments. The palladized and oxidized membranes give similar D H values but the polished membranes give values about 12% lower.

H diffusion constants have been determined from steady-state fluxes through Pd-Ag alloy membranes. The upstream side is maintained at a nearly constant pup (and consequently at a nearly constant rup=H/(Pd(1-x)Agx)) atom ratio, whereas the downstream side is at pH2 approximately 0 (rdown=0) (423-523 K). It is shown that the permeability is a maximum for atom fraction Ag, XAg=0.23 (423-523 K) at both pup=20.3 and 50.6 kPa. DH has been determined for some Pd-Ag alloys as a function of r in the dilute region, and it decreases with r even at small H contents for alloys with XAg<0.35. The concentration dependence of DH(cH) has been determined for the Pd0.77Ag0.23 alloy over a large concentration range. The effect of nonideality on DH(r) and ED(r) has been systematically determined as a function of XAg, where XAg is the atom fraction of Ag in the H-free alloy. (dDH/dr) increases with XAg up to XAg=0.35 and then changes from negative to positive at approximately 0.35. The activation energies for diffusion, ED(r), have been determined as a function of H content in the dilute range for several Pd-Ag alloy membranes, and the conversion to concentration-independent E*D values has been carried out in several different ways.

One sample of bulk Ti has been loaded with a 50%/50% deuterium/tritium (D/T) mixture and statically aged for 6.5 years. Thermal desorption of the sample shows an initial release of hydrogen isotopes followed by 3 He release. Subsequent D 2 loading/desorption was used to quantify the trapped tritium heel. The sample shows an excess hydrogen capacity as a second thermal desorption peak that partially disappears and shifts with annealing at 923-973K. The main hydrogen desorption peak also shifts to higher temperature, indicating a partial reversal of the tritium-decay induced damage by annealing.

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