Article

The fatigue behavior of irradiated Reactor Pressure Vessel steel

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Abstract

Fatigue specimens of A508-3 steel were irradiated in the swimming-pool test reactor in China Institute of Atomic Energy, the fluence was 3×10¹⁹ n/cm² at 300°C, then low-cycle fatigue tests were carried out at ambient temperature, with the fatigue strain range is 0.32-1.8%. The results indicate that, irradiated A508-3 specimens exhibit cyclic softening and instability behavior during the test, and the cyclic softening rate increased with strain range increased; fatigue life decreased from 1.7×10⁵ to about 5×10², as the strain range increased from 0.32% to 1.8%, the fatigue life of A508-3 steel increased after the neutron irradiation; fatigue fracture initiated at the surface of specimen, and more individual cracks formed on the specimens of higher strain range compared with the specimens of lower strain range.

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... However, the effect of irradiation is not generally considered in fatigue analyses of reactor structures. Some studies have carried out fatigue tests under different irradiation test conditions but obtained different (even contradictory) test conclusions [16][17][18][19]. Under certain irradiation test conditions, the fatigue life of the sample without irradiation is 1.5-2.5 times that of the sample with irradiation [16,17]. ...
... Under certain irradiation test conditions, the fatigue life of the sample without irradiation is 1.5-2.5 times that of the sample with irradiation [16,17]. However, Zhong [18] found that the fatigue life of an irradiated sample was three times greater than that of a non-irradiated sample. Another study concluded that irradiation was beneficial to fatigue life at low strain amplitudes, but not at high strain amplitudes [19]. ...
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... Lin and Zhang [9,10] conducted a formula for calculating stress concentration and strength of defective cylinder. Zhong [11] studied the fatigue behavior of irradiated reactor pressure vessel steel with experimental method. Their results are very significant, but their formulas are based on certain assumptions and simplifications. ...
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