STP1175: Fatigue Crack Growth Properties of Thermal Reactor Irradiated Nimonic PE16

    Douglas, JM
    Project Manager and Section Manager, AEA Technology, Reactor Services, Cumbria,

    Gravenor, JG
    Project Manager and Section Manager, AEA Technology, Reactor Services, Cumbria,

    Pages: 17    Published: Jan 1994


    Abstract

    Fatigue specimens were prepared from Nimonic PE16 fuel assembly components irradiated in a Commercial Advanced Gas-Cooled Reactor (CAGR) at temperatures in the range 631 K to 916 K and integrated fast neutron doses up to 21 x 1024 neutrons/m2. The tests were performed in air at temperatures from 623 K to 973 K at a frequency of 10 Hz and R-ratio (minimum/maximum load) of 0.2. Crack growth rates were correlated with the stress intensity factor range using the relation da/dN — CΔKm. The threshold stress intensity factor range, ΔKth) obtained in load-shedding tests was in the range 6 to 9 MN/m3/2 and was not markedly influenced by neutron dose, irradiation temperature or test temperature. Specimens having both uniform fine grained and non-uniform coarser grained microstructures gave similar Δth, so that roughness-induced crack closure was not a major factor, despite wide differences in crack path morphology. In tests at 973 K, somewhat higher values of ΔKth were obtained which were probably a consequence of oxide-induced closure.

    Keywords:

    fatigue, fatigue threshold, thermal reactor, nimonic PE16, irradiated


    Paper ID: STP23966S

    Committee/Subcommittee: E10.08

    DOI: 10.1520/STP23966S


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