Title: Determination of sample size to support diagnostic inspection of components

Authors: Eishiro Higo; Mahesh D. Pandey

Addresses: Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, ON, Canada ' Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, ON, Canada

Abstract: A complex engineering system like a nuclear power reactor consists of a large variety and number of engineering components. As a part of a component aging management program, the diagnostic inspections of various component populations are performed to detect the onset of any unanticipated degradation. A prudent selection of the inspection sample size is necessary to optimise inspection cost. Sample size selection is typically based on the traditional statistical hypothesis test, which tends to result in a fairly large sample size. This paper presents an alternate approach to the sample size determination (SSD) problem based on the concept of the value of information (VoI). The paper provides a comparative analysis of the VoI and hypothesis-testing approaches through illustrative examples. The VoI approach is shown to provide a more meaningful way to minimise the cost of inspection as a function of component-replacement cost and losses arising from a failure. The characteristics and advantages of the VoI approach are analysed.

Keywords: inspection; sample size determination; SSD; Bayesian analysis; value of information; VoI; hypothesis testing; decision analysis.

DOI: 10.1504/IJQET.2018.097341

International Journal of Quality Engineering and Technology, 2018 Vol.7 No.2, pp.128 - 151

Received: 07 Sep 2017
Accepted: 24 Jun 2018
Published online: 15 Jan 2019 *

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