Session: OAC-01-01 Application in Risk Management and System Reliability
Paper Number: 106365
106365 - Deterministic Leak-Before-Break Treatment of Uncertainties – Theoretical Basis
The Canadian CANDU® Industry has developed and is implementing a composite analytical approach (CAA) to demonstrate, with high confidence, appropriate safety margins for deterministic nuclear safety analysis of large-break loss-of-coolant accident events in existing CANDU reactors. A key element of the CAA is the deterministic leak-before-break (CAA/DLBB) assessment for postulated through-wall cracks in all butt welds in the large-diameter CAA in-scope piping and reactor headers.
This paper describes a systematic approach for quantifying the uncertainty in the CAA/DLBB assessment. The proposed approach integrates the uncertainties of the key leak-rate parameters into a single metric (a quantitative indicator of the uncertainty in the CAA/DLBB assessment, a.k.a., performance indicator). This approach ensures that individual key parameters are not taken out of the context of all the key parameters. A brief description of the CAA/DLBB evaluation process is presented and the leak-rate factor is adopted as the figure of merit. Next, the key leak‑rate effect factors are identified and the uncertainty in each is established. This is followed by a description of two statistical approaches that can be used to propagate the uncertainties for the bounding postulated break location and to determine the level of uncertainty associated with the CAA/DLBB assessment. In the companion paper, the application of the approach is illustrated.
Presenting Author: Maher Al-Dojayli Kinectrics Inc.
Presenting Author Biography: A technical expert at the Fitness For Service & Component Analysis, Kinectrics with a Ph.D. in Mechanical Engineering from the University of Toronto. A professional engineer with more than 20 years of in-depth experience in structural integrity assessment against plastic failures, creep, fatigue and fracture; leak before break assessment, Fitness-for-Service (FFS), ASME BPVC VIII, ASME BPVC III, ASME BPVC XI and API 579-1/ASME FFS-1.
Extensive knowledge and hands-on experience in the development and use of advanced linear and non-linear finite element methods for thermomechanical, structural static and dynamic analyses, crack propagation, optimization, fluid-structure interaction, CHT and ALE.
Authors:
Michael Kozluk CANTECH AssociatesMaher Al-Dojayli Kinectrics Inc.
Renita Pavia Bruce Power L.P.
Ernie Mileta Ontario Power Generation
Deterministic Leak-Before-Break Treatment of Uncertainties – Theoretical Basis
Paper Type
Technical Paper Publication