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Estimation of fracture toughness of cast stainless steels during thermal aging in LWR systems-revision 1

Technical Report ·
DOI:https://doi.org/10.2172/10181848· OSTI ID:10181848

This report presents a revision of the procedure and correlations presented earlier in NUREG/CR-4513, ANL-90/42 (June 1991) for predicting the change in mechanical properties of cast stainless steel components due to thermal aging during service in light water reactors at 280-330{degrees}C (535-625{degrees}F). The correlations presented in this report are based on an expanded data base and have been optimized with mechanical-property data on cast stainless steels aged up to {approx}58,000 h at 290-350{degrees}C (554-633{degrees}F). The fracture toughness J-R curve, tensile stress, and Charpy-impact energy of aged cast stainless steels are estimated from known material information. Mechanical properties of a specific cast stainless steel are estimated from the extent and kinetics of thermal embrittlement. Embrittlement of cast stainless steels is characterized in terms of room-temperature Charpy-impact energy. Charpy-impact energy as a function of time and temperature of reactor service is estimated from the kinetics of thermal embrittlement, which are also determined from the chemical composition. The initial impact energy of the unaged steel is required for these estimations. Initial tensile flow stress is needed for estimating the flow stress of the aged material. The fracture toughness J-R curve for the material is then obtained by correlating room-temperature Charpy-impact energy with fracture toughness parameters. The values of J{sub IC} are determined from the estimated J-R curve and flow stress. A common {open_quotes}predicted lower-bound{close_quotes} J-R curve for cast stainless steels of unknown chemical composition is also defined for a given grade of steel, range of ferrite content, and temperature. Examples of estimating mechanical properties of cast stainless steel components during reactor service are presented.

Research Organization:
Nuclear Regulatory Commission, Washington, DC (United States). Office of Nuclear Regulatory Research; Argonne National Lab., IL (United States)
Sponsoring Organization:
Nuclear Regulatory Commission, Washington, DC (United States)
DOE Contract Number:
W-31109-ENG-38
OSTI ID:
10181848
Report Number(s):
NUREG/CR--4513-Rev.1; ANL--93/22-Rev.1; ON: TI94018628
Country of Publication:
United States
Language:
English