Processing of high-level nuclear waste for permanent disposal will cause changes to the present inhibited compositions at the Savannah River Site. Temperature and nitrate concentration may reach new high levels during salt dissolution in the carbon steel waste tanks with certain removrd methods. Proper inhibitor concentrations are necessary to minimize the potential for nitrate-induced stress corrosion cracking to maintain the integrity of the waste tanks. Slow strain rate testing and potentiodynamic polarization were used to investigate whether stress corrosion cracking would initiate under bounding removal condhions, Test conditions for two carbon steels included nitrate concentrations of 5.5 and 9.7 M at a maximum temperature of 95 °C. The steels were found to be resistant to SCC in the more aggressive waste compositions at the present inhibitor concentrations of 0.6 M sodium hydroxide and 0.5 M sodium nitrite.
Keywords: stress corrosion cracking, carbon steels, nitrate solutions, slow strain rate testing