Effects of post-irradiation annealing and re-irradiation on microstructure in surveillance test specimens of the Loviisa-1 reactor studied by atom probe tomography and positron annihilation
Effects of post-irradiation annealing and re-irradiation on microstructure in surveillance test specimens of the Loviisa-1 reactor studied by atom probe tomography and positron annihilation
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DOI：
10.1016/j.jnucmat.2014.01.036
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发表时间：
2014-06
影响因子：
3.1
通讯作者：
T. Toyama;A. Kuramoto;Y. Nagai;K. Inoue;Y. Nozawa;Y. Shimizu;Y. Matsukawa;M. Hasegawa;M. Valo
中科院分区：
文献类型：
--
作者：
T. Toyama;A. Kuramoto;Y. Nagai;K. Inoue;Y. Nozawa;Y. Shimizu;Y. Matsukawa;M. Hasegawa;M. Valo
本文介绍了芬兰洛维萨1号反应堆监督试验样品的微观结构研究，该反应堆是俄罗斯型压水堆（VVER-440），初始辐照至2.5 × 1019 n/cm 2中子注量后（E> 1 MeV），辐照后在475 °C退火100 h，再辐照到三种不同的注量，最高可达2.7 × 10 ~（19）n/cm ~ 2。采用原子探针断层扫描（APT）和正电子湮没谱（PAS）对试样进行了表征。APT结果表明，形成富铜溶质团簇（SC）在初始照射和随后的粗化过程中退火。再次照射后，再次形成少量的SC。硬化由于SC估计使用的Russell-Brown模型的基础上的APT结果，并在初始照射和照射后退火后的测量硬化良好的协议。相比之下，在第一步的再照射，估计硬化由于SC小于测量的硬化。这表明，再照射后的硬化是由于一些微观结构以外的观察到的SC。这种差异归因于重新照射过程中新形成的基体缺陷，这得到了PAS结果的支持。然而，在随后的再辐照步骤中，硬化几乎是恒定的。
This paper presents a microstructural study of a surveillance test specimen from the Loviisa-1 reactor in Finland, which is a Russian-type pressurized water reactor (VVER-440), after initial irradiation to a neutron fluence of 2.5 × 1019n/cm2(E> 1 MeV), post-irradiation annealing at 475 °C for 100 h and re-irradiation to three different fluences up to 2.7 × 1019n/cm2. Atom probe tomography (APT) and positron annihilation spectroscopy (PAS) were used to characterize the test specimens. APT results showed the formation of Cu-rich solute clusters (SCs) during the initial irradiation and their subsequent coarsening during annealing. After re-irradiation, a small number of SCs formed once again. The hardening due to the SCs was estimated using the Russell-Brown model based on the APT results, and was in good agreement with the measured hardening after the initial irradiation and post-irradiation annealing. In contrast, during the first-step of re-irradiation, the estimated hardening due to the SCs was smaller than the measured hardening. This suggested that the hardening after re-irradiation was due to some microstructure other than the observed SCs. This difference was attributed to newly-formed matrix defects during re-irradiation, which was supported by the PAS results. However in subsequent steps of re-irradiation, the hardening was almost constant.