Effects of boric acid and lithium hydroxide on the corrosion behaviors of 316LN stainless steel in simulating hot functional test high-temperature pressurized water

The effects of boric acid and lithium hydroxide on corrosion behaviors of 316LN stainless steel (SS) in simulating hot functional test (HFT) high-temperature pressurized water at 573 K are investigated. Increasing the concentration of boric acid or lithium hydroxide degrades the corrosion resistance of 316LN SS. Boric acid is recommended for HFT water chemistry, while lithium hydroxide alone is inappropriate as HFT water chemistry. The solubility of oxides in high-temperature pressurized water is calculated and the mechanism of oxidation is discussed. A promising HFT water chemistry is also proposed. • Increasing boric acid concentration degrades corrosion resistance of 316LN SS in high-temperature B/Li water. • Corrosion resistance of 316LN SS degrades with increasing lithium hydroxide concentration in high-temperature B/Li water. • Boric acid is recommended as hot functional test water chemistry due to formation of stable Cr-rich oxide film. • Lithium hydroxide alone is inappropriate as hot functional test water chemistry since the pre-films cannot protect the substrate from further corrosion.