Views of TAGSI on effects of neutron irradiation on ductile tearing in ferritic steels

Research output: Contribution to journalReview article

Authors

Colleges, School and Institutes

Abstract

The paper reviews information pertaining to effects of neutron irradiation on "upper-shelf" Charpy impact behaviour and on elastic/plastic fracture mechanics characterising parameters, again for "upper shelf" conditions, in which the initiation and early growth of a crack involve ductile tearing. The hardening and associated reduction in strain-hardening capacity induced by irradiation gives rise to a decrease in Charpy upper shelf energy. Effects on J-based parameters are more complicated. The material resistance parameters tend to increase for low dose, but decrease at high dose, when the decrease in crack-tip ductility outweighs the effect of hardening. High doses can produce "fast shear" fracture, which propagates rapidly and is therefore more likely to induce brittle cleavage fracture. The situation is exacerbated if the irradiation also promotes inter-granular segregation and fracture, hence reducing the local brittle fracture stress. For the levels of irradiation experienced by the types of UK civil reactors in operation, no fracture instability is expected to arise as a result of ductile fracture mechanisms alone. (C) 2009 Elsevier Ltd. All rights reserved.

Details

Original languageEnglish
Pages (from-to)395-402
Number of pages8
JournalInternational Journal of Pressure Vessels and Piping
Volume86
Issue number7
Publication statusPublished - 1 Jul 2009

Keywords

  • Ferritic steels, Irradiation, Ductile fracture