Effect of oxygen concentration on the corrosion behavior of extra-high purity stainless steel SUS316EHP in liquid lead-bismuth alloy

Irisawa, Eriko ; Kato, Chiaki   

As a corrosion evaluation of stainless steel in liquid lead-bismuth alloys used as coolants for next-generation nuclear power systems, the relationship between the corrosion behaviors and the oxygen concentrations in LBE was investigated for the extra-pure stainless steel SUS316EHP, which exhibited high intergranular corrosion resistance in aqueous solution environments. Although intergranular oxidation was suppressed at high oxygen concentration, significantly faster dissolution corrosion was observed at low oxygen concentration compared to the corrosion behavior of SUS316L. The influence of chemical composition on the corrosion behavior at grain boundaries was also discussed based on microstructural observations.