The present invention relates to a method for inhibiting stress corrosion cracking
occurring on steam generator tubes in the secondary side of nuclear power plants
and an inhibitor therefor. The method comprises supplying lanthanum boride as an
inhibitor for stress corrosion cracking into the secondary feed water of the nuclear
power plants. The method according to the present invention improves the resistance
of stress corrosion cracking ten times or higher than no inhibitor, and five times
or higher than the conventional inhibitor. In particular, the method according
to the present invention shows a superior inhibiting effect in the lead-contaminated
environment such that the complete inhibition of stress corrosion cracking can
be achieved. As thus, the method can reduce the unexpected stop of operating nuclear
power plants caused by the stress corrosion cracking on steam generator tubes,
thereby reducing the cost required for maintaining and repairing the tubes.
