ISSN: 1945-7553
CODEN: JTEVAB
Page Count: 9

Fracture Mechanics Evaluation of Irradiation Embrittlement in Reactor Vessel Steels Based on the Rate Process Concept

Nogata, F
Research Associate, Himeji Institute of Technology, Himeji,

Takahashi, H
Professor, Research Institute for Strength and Fracture of Materials, Faculty of Engineering, Tohoku University, Sendai,

Abstract

A new evaluation procedure for the critical fracture toughness (K_Ic, K_Id) from Charpy-V impact absorbed energy is presented. The strain-rate/temperature effect on the cleavage-controlled fracture toughness transition is first explained by applying the concept of a stress-dependent rate process for fracture initiation. The expression described in terms of the Charpy-V energy ratio, C_v-us/C_v, for fracture toughness under a constant strain rate is newly derived. The feasibility of the new procedure for evaluating the irradiation embrittlement of reactor pressure vessel steel, such as SA533B-1, is here verified utilizing the data for both unirradiated and irradiated materials in the literature. Another method for the determination of coefficients in the new expression from the C_v-fitting curve is also presented.

Keywords:
irradiation embrittlement, toughness evaluation, fracture mechanics, reactor vessel, Charpy impact test, SA533B steel, reactor surveillance test, temperature/strain-rate effect, cleavage fracture

Paper ID: JTE10319J
DOI: 10.1520/JTE10319J
ASTM International is a member of CrossRef.