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THREE APPROACHES TO QUANTIFICATION OF NDE UNCERTAINTY AND A DETAILED EXPOSITION OF THE EXPERT PANEL APPROACH USING THE SHEFFIELD ELICITATION FRAMEWORK

Published

Author(s)

Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben, Steven R. Doctor

Abstract

The ASME Boiler & Pressure Vessel Code Section XI Committee is currently developing a new Division 2 nuclear code entitled the "Reliability and Integrity Management (RIM) program," with which one is able to arrive at a risk-informed, NDE-based engineering maintenance decision by estimating and managing all uncertainties for the entire life cycle including design, material selection, degradation processes, operation and NDE. This paper focuses on the uncertainty of the NDE method employed for preservice and inservice inspections due to a large number of factors such as the NDE equipment type and age, the operator's level and years of experience, the angle of probe, the flaw type, etc. In this paper, we describe three approaches with which uncertainty in NDE-risk-informed decision making can be quantified: (1) A regression model approach in analyzing round-robin experimental data such as the 1981-82 Piping Inspection Round Robin (PIRR), the 1986 Mini-Round Robin (MRR) on IGSCC detection and sizing, and the 1989-90 international Programme for the Inspection of Steel Components III-Austenitic Steel Testing (PISC-AST). (2) A statistical design of experiments approach. (3) An expert knowledge elicitation approach. Based on a 2003 PNNL report by Heasler and Doctor (NUREG/CR-6795), we observe that the first approach utilized round robin studies that gave NDE uncertainty information on the state of the art of the NDE technology employed from the early 1980s to the early 1990s. The DEX approach is time-consuming and costly, but has the advantage that it can be tailored to a specific defect-detection and defect-sizing problem. The third approach using an expert panel is the most efficient and least costly approach. Using the crack length results of the second approach, we introduce in this paper how the expert panel approach can be implemented with the application of a software package named the Sheffield Elicitation Framework (SHELF).
Proceedings Title
Proceedings of ASME Pressure Vessels & Piping Division Conference, July 15-20, 2018, Prague,
Czech Republic
Conference Dates
July 15-20, 2018
Conference Location
Prague, -1

Keywords

Depth sizing, design of experiments, expert knowledgment elicitation, flaw sizing, inservice inspection, intergranular stress corrosion cracking, logistic regression model, nondestructive examination, pressure vessel, probability of detection, regression model, reliability, round robin studies, SHELF, ultrasonic testing, uncertainty quantification.
Created July 15, 2018, Updated May 18, 2020