Integration of nondestructive examination reliability and fracture mechanics

Abstract

In evaluating the integrity of a system using fracture mechanics analysis, it is necessary to know the maximum size of flaws which are likely to be present. The effectiveness in reliability of nondestructive examination techniques are used to establish the probability of detection curves for different types of flaws and for different flaw characteristics, i.e., size, shape, orientation, tightness, roughness and location. This information on flaws must be known in order to ensure the systems integrity. The U.S. Nuclear Regulatory Commission has instituted a research program to establish the effectiveness and reliability of ultrasonic in-service inspections performed on light water reactor primary typing systems. This paper describes the results obtained to date and proposed methods of evaluating inspection reliability. A method has been developed for evaluating inspection reliability based on the measured variability of the inspection process. Estimates of the current level of inspection reliability have been made. Efforts are currently in progress to verify the results of these predictions and the effectiveness of the predictive model. Keywords Nondestructive Evaluation Disciplines Materials Science and EngineeringThis 3. retirement for cause is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/ cnde_yellowjackets_1981/1 INTEGRATION OF NONDESTRUCTIVE EXAMINATION RELIABILITY AND FRACTURE MECHANICS L. Becker and S. Doctor Battelle Pacific Northwest LaboratoriesRichland, Washington ABSTRACTIn evaluating the integrity of a system using fracture mechanics analysis, it is necessary to know the maximum size of flaws which are likely to be present. The effectiveness in reliability of nondestructive examination techniques are used to establish the probability of detection curves for different types of flaws and for different flaw characteristics, 1.e., size, shape, orientation, tightness, roughness and location. This information on flaws must be known in order to ensure the systems integrity. The U.S. Nuclear Regulatory Commission has instituted a research program to establish the effectiveness and reliability of ultrasonic in-service inspections performed on light water reactor primary. typing systems. This paper describes the results-obtained to date and proposed methods of evaluating inspection reliability. A method has been developed for evaluating inspection r~liability based on the measured variability of the inspection process. Estimates of the current level of inspection reliability have been made. Efforts are currently in progress to verify the results of these predictions and the effectiveness of the predictive model.