Assessment of Crack Detection in Cast Austenitic Piping Components Using Advanced Ultrasonic Methods.
Studies conducted at the Pacific N¬orthwest National Laboratory (PNNL) in Richland, Washington, have focused on developing and evaluating the reliability of nondestructive examination (NDE) approaches for inspecting coarse-grained, cast stainless steel reactor components. The objective of this work is to provide information to the United States Nuclear Regulatory Commission (NRC) on the utility, effec¬tiveness and limitations of ultrasonic testing (UT) inspection techniques as related to the in-service inspec¬tion of primary system piping components in pressurized water reactors (PWRs). Cast stainless steel pipe specimens were examined that contain thermal and mechanical fatigue cracks located close to the weld roots and have inside/outside surface geometrical conditions that simulate several PWR primary piping configurations. In addition, segments of vintage centrifugally cast piping were also examined to understand inherent acoustic noise and scattering due to grain structures and determine consistency of UT responses from different locations. The advanced UT methods were applied from the outside surface of these specimens using automated scanning devices and water coupling. The low-frequency ultrasonic method employed a zone-focused, multi-incident angle inspection protocol (operating at 250-450 kHz) coupled with a synthetic aperture focusing technique (SAFT) for improved signal-to-noise and advanced imaging capabilities. The phased array approach was implemented with a modified instrument operating at 500 kHz and composite volumetric images of the specimens were generated. Re¬sults from laboratory studies for assessing detection, localization and sizing effectiveness are discussed in this paper.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 962032
- Report Number(s):
- PNNL-SA-49933; 401001060
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
ACOUSTICS
APERTURES
Crack Dectection
DETECTION
FOCUSING
IN-SERVICE INSPECTION
Nuclear
PWR TYPE REACTORS
Piping Components
REACTOR COMPONENTS
RELIABILITY
SCATTERING
SIZE
STAINLESS STEELS
ULTRASONIC TESTING
ULTRASONIC WAVES
Ultrasonic