Investigation of mechanical properties and proton irradiation behaviors of SA-738 Gr.B steel used as reactor containment

• Published in: Nuclear materials and energy Vol. 8; no. C; pp. 18 - 22
• Main Authors: Ma, Yongzheng, Ran, Guang, Chen, Nanjun, Lei, Penghui, Shen, Qiang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2016; Elsevier
• Subjects: Irradiation behavior; Positron annihilation; Reactor containment; SA-738Gr.B steel; SA-738Gr.B steel; Positron annihilation; Reactor containment; Irradiation behavior
• ISSN: 2352-1791; 2352-1791
• DOI: 10.1016/j.nme.2016.07.010

•The mechanical properties and microstructure of as-received steels were analyzed.•At the unirradiated conditions, SA-738Gr.B steels had high tensile strength and excellent impact fracture toughness, which met the performance requirements of ASME codes.•The irradiation behaviors of SA-738Gr.B steel were investigated after irradiation with 400keV proton from 0.2dpa to 1dpa at 150ºC.•Irradiation defect density and mean positron lifetimes increased with increasing of displacement damage.•The stress-relief annealing treatment improved the ability of irradiation resistance that based on open volume defect analysis from proton irradiation. The proton irradiation behaviors of two kinds of SA-738Gr.B steels prepared by different heat treatment used as AP1000 reactor containment were investigated by transmission electron microscopy and positron annihilation lifetime spectrum (PAS). The mechanical properties of as-received steels were also measured. In the unirradiated conditions, the SA-738Gr.B steels had high tensile strength and excellent impact fracture toughness, which met the performance requirements of ASME codes. Both kinds of SA-738Gr.B steels were irradiated by 400keV proton from 1.07×1017H+/cm2 to 5.37×1017H+/cm2 fluence at 150 ºC. Some voids and dislocation loops with several nanometers were observed in the cross-section irradiated samples prepared by electroplating and then twin-jet electropolishing technology. The number of irradiation defects increased with increasing of displacement damage, as well as for the mean positron lifetimes. The stress-relief annealing treatment improved irradiation resistance based on open volume defect analysis from proton irradiation. SA-738Gr.B (SR) steel had higher proton irradiation resistance ability than that of SA-738Gr.B (QT) steel. The mechanism of irradiation behaviors were also analyzed and discussed.