Phased Array Ultrasonic Examination of Reactor Coolant System (Carbon Steel-to-CASS) Dissimilar Metal Weld Mockup Specimen

Crawford, S. L.¹  Cinson, A. D.²  Diaz, A. A.¹  Anderson, M. T.¹ 

[1] Pacific Northwest National Lab. (PNNL), Richland, WA (United States);US Nuclear Regulatory Commission (NRC), Washington, DC (United States)

关键词: CARBON STEELS;    AUSTENITIC STEELS;    ULTRASONIC TESTING;    WELDED JOINTS;    MOCKUP;    REACTOR COOLING SYSTEMS;    STAINLESS STEELS;    DEFECTS;    KHZ RANGE 100-1000;    DETECTION;    PERFORMANCE;    SIGNAL-TO-NOISE RATIO;    COMPARATIVE EVALUATIONS;    PUMPS;    ERRORS;    FREQUENCY DEPENDENCE;    INSPECTION;    NOZZLES;   

DOI  :  10.2172/1259948
RP-ID  :  PNNL--24920
PID  :  OSTI ID: 1259948
Others  :  Other: 453040374
Others  :  TRN: US1601535

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来源: SciTech Connect

【 摘 要 】

In the summer of 2009, Pacific Northwest National Laboratory (PNNL) staff traveled to the Electric Power Research Institute (EPRI) NDE Center in Charlotte, North Carolina, to conduct phased-array ultrasonic testing on a large bore, reactor coolant pump nozzle-to-safe-end mockup. This mockup was fabricated by FlawTech, Inc. and the configuration originated from the Port St. Lucie nuclear power plant. These plants are Combustion Engineering-designed reactors. This mockup consists of a carbon steel elbow with stainless steel cladding joined to a cast austenitic stainless steel (CASS) safe-end with a dissimilar metal weld and is owned by Florida Power & Light. The objective of this study, and the data acquisition exercise held at the EPRI NDE Center, were focused on evaluating the capabilities of advanced, low-frequency phased-array ultrasonic testing (PA-UT) examination techniques for detection and characterization of implanted circumferential flaws and machined reflectors in a thick-section CASS dissimilar metal weld component. This work was limited to PA-UT assessments using 500 kHz and 800 kHz probes on circumferential flaws only, and evaluated detection and characterization of these flaws and machined reflectors from the CASS safe-end side only. All data were obtained using spatially encoded, manual scanning techniques. The effects of such factors as line-scan versus raster-scan examination approaches were evaluated, and PA-UT detection and characterization performance as a function of inspection frequency/wavelength, were also assessed. A comparative assessment of the data is provided, using length-sizing root-mean-square-error and position/localization results (flaw start/stop information) as the key criteria for flaw characterization performance. In addition, flaw signal-to-noise ratio was identified as the key criterion for detection performance.