Improvements in Low-Frequency, Ultrasonic Phased-Array Evaluation for Thick Section Cast Austenitic Stainless Steel Piping Components

Conference · Wed Dec 01 04:00:00 EST 2010

OSTI ID:1032700

Anderson, Michael T; Crawford, Susan L; Diaz, Aaron A; Moran, Traci L

Research is being conducted for the U.S. Nuclear Regulatory Commission (NRC) at the Pacific Northwest National Laboratory (PNNL) to assess the effectiveness and reliability of advanced nondestructive examination (NDE) methods for the inspection of light water reactor (LWR) components. A primary objective of this work is to evaluate various NDE methods to assess their ability to detect, localize, and size cracks in coarse-grained steel components. This particular study focused on the evaluation of custom-designed, low-frequency (500 kHz) phased-array (PA) probes for examining welds in thick-section cast austenitic stainless steel (CASS) piping. In addition, research was conducted to observe ultrasonic sound field propagation effects from known coarse-grained microstructures found in parent CASS material. The study was conducted on a variety of thick-wall, coarse-grained CASS specimens that were previously inspected by an older generation 500-kHz PA-UT probe and acquisition instrument configuration. This comparative study describes the impact of the new PA probe design on flaw detection and sizing in a low signal-to-noise environment. The set of Pressurized Water Reactor Owners Group (PWROG) CASS specimens examined in this study are greater than 50.8-mm (2.0-in.) thick with documented flaws and microstructures. These specimens are on loan to PNNL from the Electric Power Research Institute (EPRI) NDE Center in Charlotte, North Carolina. The flaws contained within these specimens are thermal fatigue cracks (TFC) or mechanical fatigue cracks (MFC) and range from 13% to 42% in through-wall extent. In addition, ultrasonic signal continuity was evaluated on two CASS parent material ring sections by examining the edge-of-pipe response (corner geometry) for regions of signal loss.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1032700
• Report Number(s): PNNL-SA-75184; 401001060
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
CONFIGURATION
Cast Austenitic Stainless Steel Piping
DEFECTS
DESIGN
DETECTION
EPRI
EVALUATION
GEOMETRY
PROBES
PWR TYPE REACTORS
RELIABILITY
SIZE
STAINLESS STEELS
STEELS
THERMAL FATIGUE
ULTRASONIC WAVES
Ultrasonic Phased Array
WATER