Crack Growth Rate and Fracture Toughness Tests on Irradiated Cast Stainless Steels

Technical Report · Thu Jun 06 04:00:00 EDT 2013

DOI:https://doi.org/10.2172/1084189· OSTI ID:1084189

Chen, Y. ^[1]; Alexandreanu, B. ^[1]; Natesan, K. ^[1]

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1. Argonne National Laboratory (ANL), Argonne, IL (United States)

Cast austenitic stainless steels are used in the cooling system of light water reactors for components with complex shapes, such as pump casings, valve bodies, and coolant piping. In the present study, crack growth rate and fracture toughness JR curve tests were performed on irradiated cast stainless steels in low-corrosion-potential environments (low-dissolved-oxygen high-purity water or simulated pressurized water reactor environment) at 320°C. Both as received and thermally aged materials were included to investigate the combined effect of thermal aging and irradiation embrittlement on the fracture behavior of cast stainless steels. The samples were irradiated to approximately 0.08 dpa at the Halden reactor. Good resistance to corrosion fatigue and stress corrosion cracking was observed for all samples. Thermal aging had little effect on the crack growth behavior at this dose level. Cleavage-like fracture was the dominant cracking morphology during the crack growth rate tests, and the ferrite phase was deformed to a lesser extent compared with the surrounding austenite phase. The fracture toughness results showed a dominant effect of neutron irradiation, and the fracture resistances were decreased considerably for all cast specimens regardless of their thermal aging conditions. The reduction in fracture toughness was more significant in the unaged than thermally aged materials. Nonetheless, the fracture toughness values of thermally aged specimens were about 30% lower than their unaged counterparts, suggesting a combined effect of thermal aging and neutron irradiation in cast stainless steel.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USNRC
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1084189
• Report Number(s): ANL--12/56
• Country of Publication: United States
• Language: ENGLISH