Estimation of fracture toughness of cast stainless steels during thermal aging in LWR systems

Technical Report · Sat Jun 01 00:00:00 EDT 1991

DOI:https://doi.org/10.2172/5561283· OSTI ID:5561283

Chopra, O K ^[1]

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1. Argonne National Lab., IL (USA)

A procedure and correlations are presented for predicting the change in fracture toughness of cast stainless steel components due to thermal aging during service in light water rectors (LWRs) at 280--330{degrees}C (535--625{degrees}F). The fracture toughness J-R curve and Charpy-impact energy of aged cast stainless steels are estimated from known mineral in formation. Fracture toughness of a specific cast stainless steel is estimated from the extent and kinetics of thermal embrittlement. The extent of thermal embrittlement is characterized by the room-temperature normalized'' Charpy-impact energy. A correlation for the extent of embrittlement at saturation,'' i.e., the minimum impact energy that would be achieved for the material after long-term aging, is given in terms of a material parameter, {Phi}, which is determined from the chemical composition. The fracture toughness J-R curve for the material is then obtained from correlations between room-temperature Charpy-impact energy and fracture toughness parameters. Fracture toughness as a function of time and temperature of reactor service is estimated from the kinetics of thermal embrittlement, which is determined from chemical composition. A common lower-bound'' J-R curve for cast stainless steels with unknown chemical composition is also defined for a given material specification, ferrite content, and temperature. Examples for estimating impact strength and fracture toughness of cast stainless steel components during reactor service are describes. 24 refs., 39 figs., 2 tabs.

• Research Organization: Nuclear Regulatory Commission, Washington, DC (USA). Div. of Engineering; Argonne National Lab., IL (USA)
• Sponsoring Organization: NRC; Nuclear Regulatory Commission, Washington, DC (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5561283
• Report Number(s): NUREG/CR-4513; ANL--90/42; ON: TI91014221
• Country of Publication: United States
• Language: English

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