Observation of tritium distribution in low-activation V-4Cr-4Ti alloy by radioluminography

Tritium radioluminography has been applied to the observation of tritium distribution in electro-chemically tritium charged pure V and V-4Cr-4Ti alloy (NIFS-HEAT-2) specimens, and the relation between the tritium distribution and the microstructure has been examined. In the cold rolled V-4Cr-4Ti alloy specimen, tritium distribution showed band-like morphology along the rolling direction. This tritium accumulated band is corresponded to the band-like structure formed by high densely precipitated fine Ti granules. On the other hand, band-like morphology of tritium accumulation was not observed in the pure V and Ti-precipitation free V-4Cr-4Ti alloy specimen. The Ti-precipitate is concluded to be a strong trapping site for tritium. The tritium segregation to the grain boundary was not recognized both in the pure V and V-4Cr-4Ti alloy specimen indicating that the trapping power of the grain boundary for tritium is weak.