Radiation-induced alkali formation and its effect on the corrosion of Grade-12 titanium in rock salt nuclear waste repositories

摘要

Natural rock salt was gamma irradiated at a dose rate of 8 x 10/sup 6/ rad/h for times up to 1338 h. Subsequent dissolution in water produced high pH solutions. The corrosion properties of ASTM Grade-12 titanium were evaluated in simulated alkaline rock salt brines. The uniform corrosion rates were enhanced compared to those for neutral solutions, but crevice corrosion rates were retarded because of difficulties in obtaining high acidity in the crevice region. Hydrogen uptake was enhanced because of the chemical dissolution of the oxide layer. Upon hydrogenation, tensile samples showed slow-strain-rate embrittlement. Stress corrosion cracking, however, was not detected in the alkaline brines. 23 references, 8 figures, 6 tables.