Effect of non-uniform reactor cooling on fracture and constraint of a reactor pressure vessel

Qian, Guian; Niffenegger, Markus; Sharabi, Medhat; Lafferty, Nathan

Abstract

In the lifetime prediction and extension of a nuclear power plant, a reactor pressure vessel (RPV) has to demonstrate the exclusion of brittle fracture. This paper aims to apply fracture mechanics to analyse the non‐uniform cooling effect in case of a loss‐of‐coolant accident on the RPV integrity.

A comprehensive framework coupling reactor system, fluid dynamics, fracture mechanics, and probabilistic analyses for the RPVs integrity analysis is proposed. The safety margin of the allowed RTNDT is increased by more than 16°C if a probabilistic method is applied. Considering the non‐uniform plume cooling effect increases KI more than 30%, increases the failure frequency by more than 1 order of magnitude, and increases the crack tip constraint due to the resulting higher stress. Thus, in order to be more realistic and not to be nonconservative, 3D computational fluid dynamics may be required to provide input for the fracture mechanics analysis of the RPV.

Citation

Qian, G., Niffenegger, M., Sharabi, M., & Lafferty, N. (2018). Effect of non-uniform reactor cooling on fracture and constraint of a reactor pressure vessel. Fatigue and Fracture of Engineering Materials and Structures, 41(7), 1559-1575. https://doi.org/10.1111/ffe.12796

• Journal Article Type: Article
• Acceptance Date: Feb 4, 2018
• Online Publication Date: Mar 12, 2018
• Publication Date: Jul 31, 2018
• Deposit Date: Apr 4, 2018
• Publicly Available Date: Mar 13, 2019
• Journal: Fatigue and Fracture of Engineering Materials and Structures
• Print ISSN: 8756-758X
• Electronic ISSN: 1460-2695
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 41
• Issue: 7
• Pages: 1559-1575
• DOI: https://doi.org/10.1111/ffe.12796
• Keywords: Constraint effect; Crack propagation; Pressurized thermal shock; Probabilistic fracture mechanics; Reactor pressure vessel; Stress intensity factor
• Public URL: https://nottingham-repository.worktribe.com/output/948335
• Publisher URL: https://onlinelibrary.wiley.com/doi/abs/10.1111/ffe.12796
• Additional Information: This is the peer reviewed version of the following article: Qian G, Niffenegger M, Sharabi M, Lafferty N. Effect of non-uniform reactor cooling on fracture and constraint of a reactor pressure vessel. Fatigue Fract Eng Mater Struct. 2018;41:1559–1575. https://doi.org/10.1111/ffe.12796, which has been published in final form at https://onlinelibrary.wiley.com/doi/abs/10.1111/ffe.12796. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
• Contract Date: Apr 4, 2018