Comparison of irradiation-induced shifts of KJc and Charpy impact toughness for reactor pressure vessel steels

Mikhail A. Sokolov, Randy K. Nanstad

Research output: Contribution to journalConference articlepeer-review

61 Scopus citations

Abstract

The current provisions for determination of the upward temperature shift of the lower-bound static fracture toughness curve due to irradiation of reactor pressure vessel steels are based on the assumption that they are the same as the Charpy 41-J shifts as a consequence of irradiation. The objective of this paper is to evaluate this assumption relative to data reported in open publications. Depending on the specific source, different sizes of fracture toughness specimens, procedures of the KJc determination, and fitting functions were used. It was anticipated that the scatter might be reduced by using a consistent approach to analyze the published data. A method employing Weibull statistics is applied to analyze original fracture toughness data of unirradiated and irradiated pressure vessel steels. Application of the master curve concept is used to determine shifts of fracture toughness transition curves. A hyperbolic tangent function is used to fit Charpy absorbed energy data. The fracture toughness shifts are compared to Charpy impact shifts evaluated with various criteria. Linear regression analysis showed that for weld metals, on average, the fracture toughness shift is the same as the Charpy 41-J temperature shift, while for base metals, on average, the fracture toughness shift at 41 J is 16% greater than the shift of the Charpy 41-J transition temperature, with both correlations having relatively large 95% confidence intervals.

Original languageEnglish
Pages (from-to)167-190
Number of pages24
JournalASTM Special Technical Publication
Issue number1325
StatePublished - 1999
EventProceedings of the 1996 18th International Symposium: Effects of Radiation on Materials - Hyannis, MA, USA
Duration: Jun 25 1996Jun 27 1996

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