Understanding the Effect of Oxygen on the Degradation of 316L in Liquid Sodium

Electrification, combined with the growth in artificial intelligence and data centers, has greatly increased demand for continuous power. This demand has led to a nuclear resurgence since nuclear reactors offer consistent baseload power and have maximum uptime amongst power plants, both of which are essential. Sodium-cooled fast reactors (SFRs) offer the necessary power requirements, integration with renewable energy systems and minimal nuclear waste generation. However, the reactivity of the liquid sodium coolant and high operating temperatures pose a significant risk to plant safety. Therefore, a thorough understanding of the mechanisms of liquid sodium corrosion under ideal and transient impurity conditions is required. This work investigates liquid sodium corrosion mechanisms in candidate SFR alloys when exposed to varied oxygen concentrations. A high-throughput, oxygen-controlled liquid sodium corrosion testing vessel was designed and commissioned to systematically evaluate corrosion behavior of 316L stainless steel. 100-hour exposures were performed on 316L under purified Na with varying oxygen concentrations at 550 °C. NaCrO2 was the dominant phase present at all oxygen levels with increased intergranular oxidation observed at higher concentrations. Carbides transitioned from Cr23C6 under purified conditions to (Fe, Mo)6C at intermediate oxygen concentration. Redeposited ferrite particles were observed to increase in size with increased oxygen content, suggesting enhanced iron solubility in oxygen contaminated sodium. These findings provide the basis for predicting material degradation during transient oxygen introductions in SFR plants.

Level thesis:degree_level

Master’s Degree

Year dc:date.issued

2026

Author dc:creator

• Skov Black, Tolin

Advisor dc:contributor.advisor

• Chidambaram, Dev

Committee members dc:contributor.committeemember

• Chidambaram, Dev
• Nesbitt, Carl
• Moon, Jeremy

• Austenitic
• Corrosion
• Oxygen
• Sodium

Language dc:language.iso

en_US, English

Repository record dc:identifier.uri

https://scholarwolf.unr.edu/handle/11714/11960

OAI identifier oai:identifier

oai:scholarwolf.unr.edu:11714/11960