In-situ WB-STEM observation of dislocation loop behavior in reactor pressure vessel steel during post-irradiation annealing

摘要: Abstract To better understand the thermal stability of dislocation loops formed by long-term neutron irradiation in reactor pressure vessel (RPV) steels, in-situ scanning transmission electron microscopy (STEM) observation was performed for a surveillance test specimen European pressurized water (PWR). The irradiated to fluence 8.2 × 1023 neutrons•m−2. A membrane sample from annealed at 673 K and 723 K 30 min using heating holder, same area observed under STEM. After annealing, with Burgers vectors ½ 〈111〉 〈100〉 were quantitatively examined. When annealing temperature increased 723 K, number decreases, whereas size them becomes larger. Correspondingly, proportion changes 27% 45%. ratio increases rising. evolution process during analyzed shed light on transformation mechanism going 〈100〉. It is first time directly observe that two collide each other coalesce form loop. Moreover, small could be absorbed large loops, vector remained unchanged. Dislocation decoration occurs due interaction between dislocations loops. decorated are pretty stable continuous process, which well explained molecular dynamics simulation.