Long-term embrittlement of cast duplex stainless steels in LWR (light water reactor) systems

Technical Report · Thu Feb 01 04:00:00 EST 1990

DOI:https://doi.org/10.2172/7077485· OSTI ID:7077485

Chopra, O. K.; Chung, H. M. ^[1]

---

1. Argonne National Lab., IL (USA)

This progress report summarizes work performed by Argonne National Laboratory on long-term embrittlement of cast duplex stainless steels in LWR systems during the six months from October 1987 to March 1988. A mechanistic understanding of the activation energy of aging is described on the basis of the results of microstructural characterization of various heats of Grades CF-3, CF-8, and CF-8M stainless steel that were used in aging studies at different laboratories. The kinetics of the spinodal decomposition of ferrite (i.e., the primary mechanism of aging embrittlement) appear to be strongly influenced by a synergistic effect of G-phase nucleation and growth. When the activation energies (ranging from 18 to 50 kcal/mole) were plotted as a function of the volume fraction of G phase produced during accelerated aging, a good correlation was obtained regardless of variations in grade, bulk chemical composition, and fabrication process. Spinodal-like decomposition of austenite in heats containing a relatively high level of Ni has also been investigated. Charpy-impact data for thermally aged cast stainless steel were analyzed to determine the kinetics and extent of embrittlement. The ferrite morphology had a strong effect on the extent of embrittlement, whereas the material composition influenced the kinetics of embrittlement. Results obtained from the present study of mechanical properties, and data of other investigators were analyzed to develop the procedure and correlations for predicting the kinetics and extent of embrittlement, under reactor operating conditions, from the material parameters. 31 refs., 30 figs., 1 tab.

• Research Organization: Nuclear Regulatory Commission, Washington, DC (USA). Div. of Engineering; Argonne National Lab., IL (USA)
• Sponsoring Organization: NRC
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 7077485
• Report Number(s): NUREG/CR-4744-Vol.3-No.1; ANL--89/22-Vol.3-No.1; ON: TI90007411
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210100* -- Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled
210200 -- Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
36 MATERIALS SCIENCE
360103 -- Metals & Alloys-- Mechanical Properties
ACTIVATION ENERGY
AGING
ALLOYS
ANNEALING
BWR TYPE REACTORS
CARBIDES
CARBON COMPOUNDS
CHARPY TEST
CHEMICAL COMPOSITION
CRYSTAL STRUCTURE
DESTRUCTIVE TESTING
DOCUMENT TYPES
EMBRITTLEMENT
ENERGY
FABRICATION
HARDNESS
HEAT TREATMENTS
HIGH ALLOY STEELS
IMPACT TESTS
IRON ALLOYS
IRON BASE ALLOYS
KINETICS
MATERIALS
MATERIALS TESTING
MECHANICAL PROPERTIES
MECHANICAL TESTS
MICROSTRUCTURE
PROGRESS REPORT
PWR TYPE REACTORS
REACTOR MATERIALS
REACTORS
STAINLESS STEELS
STEELS
TESTING
WATER COOLED REACTORS
WATER MODERATED REACTORS