Strain-based plastic instability acceptance criteria for ferritic steel safety class 1 nuclear components under level D service loads

Ji Su Kim, Han Sang Lee, Jong Sung Kim, Yun Jae Kim, Jin Won Kim

Research output: Contribution to journalArticle

3 Citations (Scopus)


This paper proposes strain-based acceptance criteria for assessing plastic instability of the safety class 1 nuclear components made of ferritic steel during level D service loads. The strain-based criteria were proposed with two approaches: (1) a section average approach and (2) a critical location approach. Both approaches were based on the damage initiation point corresponding to the maximum load-carrying capability point instead of the fracture point via tensile tests and finite element analysis (FEA) for the notched specimen under uni-axial tensile loading. The two proposed criteria were reviewed from the viewpoint of design practice and philosophy to select a more appropriate criterion. As a result of the review, it was found that the section average approach is more appropriate than the critical location approach from the viewpoint of design practice and philosophy. Finally, the criterion based on the section average approach was applied to a simplified reactor pressure vessel (RPV) outlet nozzle subject to SSE loads. The application shows that the strain-based acceptance criteria can consider cumulative damages caused by the sequential loads unlike the stress-based acceptance criteria and can reduce the overconservatism of the stress-based acceptance criteria, which often occurs for level D service loads.

Original languageEnglish
Pages (from-to)340-350
Number of pages11
JournalNuclear Engineering and Technology
Issue number3
Publication statusPublished - 2015 Jan 1



  • Components
  • Damage initiation model
  • Finite element analysis
  • Level D service loads
  • Plastic instability
  • Safety class 1 nuclear
  • Strain-based acceptance criteria

ASJC Scopus subject areas

  • Nuclear Energy and Engineering

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