It was found that an oxide film which was produced during heating (140h) in He had the effect of reducing the amount of permeated isotope. It was found that the data for 570 to 820C and 106 to 3950Pa (H), and for 570 to 820C and 989 to 4040Pa (D) could be described by:

H:     P (cm2/svPa) = 1.0 x 10-4 exp[-67.2(kJ/mol)/RT]

D:     P (cm2/svPa) = 2.5 x 10-4 exp[-76.6(kJ/mol)/RT]

Permeability of Hydrogen Isotope through Hastelloy XR in the HTTR Hydrogen Production System. T.Takeda, J.Iwatsuki, Y.Inagaki, M.Ogawa: Journal of the Atomic Energy Society of Japan, 2000, 42[3], 204-11