The feasibility of prefatigued sub size specimens to fracture mechanical studies in inert and in reactor environments

Aki Toivonen, Pekka Moilanen, Seppo Tähtinen, Pertti Aaltonen, Kim Wallin

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsProfessional

    Abstract

    The feasibility of sub size specimens to fracture mechanical tests in inert and in reactor environment is studied in this paper. The need for using sub size specimens has arised from the need to study highly irradiated materials as well as to study localised stress corrosion cracking, i.e. stress corrosion cracking in very narrow heat affected zones for example in welded thin walled pipes. This paper focuses on the effects of high J-integral values on ductile tearing and on environmentally assisted crack growth rate. The main focus is on the stress corrosion tests. The subject is approached first by theoretical discussion. The experimental study consists of J-R tests in air and of slow J-R tests in simulated boiling water reactor (BWR) environment. In most cases the tests were continued until the J-integral level was significantly above the maximum allowable J values for ductile fracture toughness characterisation prescribed in test standards. The results indicate that the measurement capacity of the specimens depends on the specimen dimensions in J-R tests in air, as could be expected. The measurement capacity limitations are not necessarily important in stress corrosion testing as the environmentally assisted crack growth rate can be measured even without exceeding the J-integral limits given in J-R standards. The theoretical and experimental studies indicate that stress corrosion studies are not limited to linear elastic fracture mechanics approach, but elastic plastic fracture mechanics is applicable as well.
    Original languageEnglish
    Title of host publicationEnlarged Halden programme group meeting on high burn-up fuel performance, safety and reliability and degradation of in-core materials and water chemistry effects and man-machine systems research
    Number of pages18
    Publication statusPublished - 1998
    MoE publication typeD3 Professional conference proceedings
    EventEnlarged Halden Programme Group Meeting, EHPG 1998 - Lillehammer, Norway
    Duration: 15 Mar 199820 Mar 1998

    Publication series

    SeriesOECD Halden Reactor Project
    NumberHPR-349/45

    Conference

    ConferenceEnlarged Halden Programme Group Meeting, EHPG 1998
    CountryNorway
    CityLillehammer
    Period15/03/9820/03/98

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