Dissolutions of oxide dispersion strengthened ferritic steels in various nitric acid solutions; Martensitic 9Cr-ODS steels

Inoue, Masaki ; Ikeuchi, Hirotomo  ; Takeuchi, Masayuki ; Koyama, Shinichi  ; Suto, Mitsuo

Corrosion resistance of fuel pin cladding tube materials is one of the most important properties to design aqueous reprocessing process. The martensitic oxide dispersion strengthened ferritic steel, names as "9Cr-ODS" steel, is the primary candidate of high burnup fuel pin cladding tube for fast reactor cycle. Because 9Cr-ODS steel contains lower chromium than stainless steels, oxidizing species in nitric acid medium needs to reduce its corrosion rate. In spent fuel dissolvers, although both nitric acid and metallic ions concentrations change, corrosion potential of 9Cr-ODS steel tends to increase gradually and stabilize protective passive layer effectively.