Nondestructive characterization of embrittlement in reactor pressure vessel steels -- A feasibility study

Technical Report · Sun Mar 01 04:00:00 EST 1998

DOI:https://doi.org/10.2172/305907· OSTI ID:305907

McHenry, H. I.; Alers, G. A. ^[1]

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1. National Inst. of Standards and Technology, Boulder, CO (United States). Materials Reliability Div.

The Nuclear Regulatory Commission recently initiated a study by NIST to assess the feasibility of using physical-property measurements for evaluating radiation embrittlement in reactor pressure vessel (RPV) steels. Ultrasonic and magnetic measurements provide the most promising approaches for nondestructive characterization of RPV steels because elastic waves and magnetic fields can sense the microstructural changes that embrittle materials. The microstructural changes of particular interest are copper precipitation hardening, which is the likely cause of radiation embrittlement in RPV steels, and the loss of dislocation mobility that is an attribute of the ductile-to-brittle transition. Measurements were made on a 1% copper steel, ASTM grade A710, in the annealed, peak-aged and overaged conditions, and on an RPV steel, ASTM grade A533B. Nonlinear ultrasonic and micromagnetic techniques were the most promising measures of precipitation hardening. Ultrasonic velocity measurements and the magnetic properties associated with hysteresis-loop measurements were not particularly sensitive to either precipitation hardening or the ductile-to-brittle transition. Measurements of internal friction using trapped ultrasonic resonance modes detected energy losses due to the motion of pinned dislocations; however, the ultrasonic attenuation associated with these measurements was small compared to the attenuation caused by beam spreading that would occur in conventional ultrasonic testing of RPVs.

• Research Organization: Nuclear Regulatory Commission, Office of Nuclear Regulatory Research, Washington, DC (United States); Brookhaven National Lab., Upton, NY (United States)
• Sponsoring Organization: National Inst. of Standards and Technology, Gaithersburg, MD (United States); Nuclear Regulatory Commission, Washington, DC (United States)
• OSTI ID: 305907
• Report Number(s): NUREG/CP--0162-Vol.1; CONF-9710101--Vol.1; ON: TI98007503
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
EMBRITTLEMENT
EXPERIMENTAL DATA
LOW ALLOY STEELS
MAGNETIC TESTING
MICROSTRUCTURE
PHYSICAL RADIATION EFFECTS
PRESSURE VESSELS
STEEL-ASTM-A533-B
ULTRASONIC TESTING
WATER COOLED REACTORS