Studies on the causes of failures in titanium tube condensers of nuclear power plants

The amount of hydrogen absorbed in Ti tubes varies as the surface condition of Ti tubes changes. It was observed that the amount of hydrogen absorbed in Ti tubes was highest in as-received and welded specimens, while that could be reduced by oxidizing them to make stable oxide surface film or by pickling them. The results of the experiments done by varing the applied cathodic potentials show that hydrogen content absorbed in Ti tubes increases very sharply at or below the potential of -0.9 V versus SCE, which suggests that critical potential for cathodic protection should be above -0.9 V versus SCE. (Author)