STP1270

    The Modelling of Irradiation Embrittlement in Submerged-Arc Welds

    Published: Jan 1996


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    Abstract

    Until very recently, the irradiation embrittlement behaviour of submerged-arc welds has been interpreted in terms of two mechanisms, namely a matrix damage component and an additional component due to the irradiation-enhanced production of copper-rich precipitates.

    However, some of the weld specimens from a recent accelerated re-irradiation experiment have shown high Charpy shifts which exceeded the values expected from the measured shift in yield stress. Microstructural examination has revealed the occurrence of intergranular fracture (IGF) in these specimens, accompanied by grain boundary segregation of phosphorus.

    Theoretical models were developed to predict the parametric dependence of irradiation-enhanced phosphorus segregation on experimental variables. Using these parametric forms, along with the concept of a critical level of segregation for the onset of IGF instead of cleavage, a three mechanism trend curve has been developed. The form of this trend curve, taking into account IGF as well as matrix and copper embrittlement, is thus mechanistically based. The constants in the equation, however, are obtained by a statistical fit to the actual Charpy shift database.

    Keywords:

    pressure vessels, irradiation, embrittlement, intergranular fracture


    Author Information:

    Bolton, CJ
    Nuclear Electric plc, Berkeley Technology Centre, Berkeley, Gloucestershire

    Buswell, JT
    Nuclear Electric plc, Berkeley Technology Centre, Berkeley, Gloucestershire

    Jones, RB
    Nuclear Electric plc, Berkeley Technology Centre, Berkeley, Gloucestershire

    Moskovic, R
    Nuclear Electric plc, Berkeley Technology Centre, Berkeley, Gloucestershire

    Priest, RH
    Nuclear Electric plc, Berkeley Technology Centre, Berkeley, Gloucestershire


    Paper ID: STP16470S

    Committee/Subcommittee: E10.08

    DOI: 10.1520/STP16470S


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