Location

Brunswick, ME

Start Date

1-1-1990 12:00 AM

Description

The purpose of ultrasonic inservice inspection (UT/ISI) of nuclear reactor piping and pressure vessels is the reliable detection and sizing of material defects. Before defects can be sized, they must first be detected. This is typically done by analyzing ultrasonic echo waveforms with an amplitude greater than a certain percentage of that of a calibration reflector such as a 10% notch [1]. Studies performed at Pacific Northwest Laboratory (PNL) [2] and elsewhere [3–5] have shown that changing the components of an ultrasonic inspection system can greatly affect echo amplitude from a defect even when conventional calibration procedures are used, thus reducing the reliability of defect detection. To address this problem, ASME code [6] has provided tolerance levels for equipment parameters (e.g., center frequency and bandwidth) when inspection components are changed. However, some of the code requirements are based on engineering judgement and lack a strong analytical foundation. In this paper, the results of sensitivity studies performed to determine the effects of equipment parameter changes to provide an analytical basis for ASME code are presented.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

9A

Chapter

Chapter 4: Probes, Sensors, and Inspectability

Section

Inspectability

Pages

901-908

DOI

10.1007/978-1-4684-5772-8_114

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

The Effect of Equipment Bandwidth and Center Frequency Changes on Ultrasonic Inspection Reliability: Modeling and Experimentation Results

Brunswick, ME

The purpose of ultrasonic inservice inspection (UT/ISI) of nuclear reactor piping and pressure vessels is the reliable detection and sizing of material defects. Before defects can be sized, they must first be detected. This is typically done by analyzing ultrasonic echo waveforms with an amplitude greater than a certain percentage of that of a calibration reflector such as a 10% notch [1]. Studies performed at Pacific Northwest Laboratory (PNL) [2] and elsewhere [3–5] have shown that changing the components of an ultrasonic inspection system can greatly affect echo amplitude from a defect even when conventional calibration procedures are used, thus reducing the reliability of defect detection. To address this problem, ASME code [6] has provided tolerance levels for equipment parameters (e.g., center frequency and bandwidth) when inspection components are changed. However, some of the code requirements are based on engineering judgement and lack a strong analytical foundation. In this paper, the results of sensitivity studies performed to determine the effects of equipment parameter changes to provide an analytical basis for ASME code are presented.