STP1405

    Crack Growth Resistance of Irradiated Zr-2.5Nb Pressure Tube Material at Low Hydrogen Levels

    Published: Jan 2001


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    Abstract

    The primary factors influencing the crack growth resistance of irradiated Zr-2.5Nb pressure tube material at low concentrations of hydrogen/deuterium are reviewed. These factors include the initial characteristics of the material, which have brought about improvements in the toughness, and the operating conditions in reactor. The paper presents an update on the current status of this work using J-R curves. Such curves are determined from curved compact and rising-pressure burst test specimens at 250°C, i.e., the lower end of the operating temperature range. Some of the challenges encountered in assessing the crack growth toughness of this high-strength, thin-walled material are discussed. The role of chlorine, known to be responsible for the presence of Zr-Cl-C particles and preferential decohesion and fissuring, is also highlighted. The results from the curved compact specimens suggest a limiting level of chlorine above which no further significant degradation in crack growth resistance occurs. This level of chlorine is about 3 wt ppm for material having a low concentration of zirconium phosphide (P < 20 wt ppm). Such results require confirmation using burst tests on material with intermediate levels of chlorine and low levels of zirconium phosphide.

    Keywords:

    crack growth resistance (J-R) curve, fracture toughness, Zr-2.5Nb, pressure tube, irradiation, slant fracture


    Author Information:

    Davies, PH
    Senior research scientist, AECL,Chalk River Laboratories, Chalk River, Ontario

    Himbeault, DD
    research scientist, AECL, Whiteshell Laboratories, Pinawa, Manitoba

    Shewfelt, RSW
    Research scientist, AECL, Whiteshell Laboratories, Pinawa, Manitoba

    Hosbons, RR
    Head, AECL, Chalk River Laboratories, Chalk River, Ontario


    Paper ID: STP10577S

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP10577S


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