SCC Inhibitors for SG Tube Materials in Nuclear Power Plants

摘要

Several chemicals were studied to suppress the damage due to stress corrosion cracking (SCC) of steam generator (SG) tubes in nuclear power plants. The polarization curves showed that the electrochemical properties on the surface of Alloy 600 MA changed with the addition of inhibitors. The SCC tests were conducted by using a m-RUB specimen in a 10% NaOH solution at a temperature of 315 ℃. The effects on the SCC of the compounds, TiO_2, TyzorLA and CeB_6, were tested for several types of SG tubing materials. The test with the addition of TiO_2 (P25) and CeE$6 showed an effect in decreasing the SCC for the SG tubing material. However, CeB_6 caused some more SCC for Alloy 800. The penetration property into a crevice of the inhibitors was investigated by using Alloy 600 specimens with different gap sizes and an AES analysis was performed on the oxide layer of the specimen.