Reactor Pressure Vessel (RPV) has been an indispensable part in the nuclear power plant. As the key component of RPV steel, α-Fe is under neutron irradiation during its long-term service. With long-term exposure, lattice atoms of α-Fe are knocked by neutron, which leads to irradiation damage. In this paper, molecular dynamics method is conducted to investigate the effect of vacancy concentration, tensile strain, and temperature on irradiation-induced damage by displacement cascade simulations in α-Fe. The simulations are performed with primary knock-on atom energies ranging from 0.1 to 10 keV, vacancy concentration ranging from 0% to 2%, applied tensile strain ranging from 0 to 5%, and temperature ranging from 100 to 500K. It is demonstrated that many vacancies, interstitials and other defect clusters can be observed during displacement cascades. The time evolution of defects produced during displacement cascade can be obtained for each case. The influence of these factors on defect production can be concluded as following: The increase of PKA energy and applied tensile strain can lead to the increase of defect numbers. In contrast, the increase of vacancy concentration and temperature decrease the defect numbers. Note that the existence of preset vacancy accelerates the annihilation of point defects in displacement cascade. Vacancies and interstitials cluster size distributions are varied in different case. The results are meaningful to describe some microcosmic mechanisms of RPV steels in nuclear system.


Study on the Effect of Different Factors of Displacement Cascades in Alpha-Fe by Molecular Dynamics Simulations

Division / Sponsors: 
Power Division & Nuclear Engineering Division (NED)

Power Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/POWER/POWER2020/volume/83747

International Conference on Nuclear Engineering
Paper Proceedings: https://asmedigitalcollection.asme.org/ICONE/ICONE2020/volume/83761

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