Proton irradiation with a primary ion energy of 2 MeV was used to simulate radiation damage in UN and (U,Zr)N fuel pellets. The pellets, nominally at room temperature, were irradiated to peak levels of 0.1, 1, 10 dpa and 100 dpa resulting in a peak hydrogen concentration of at most 1 at. %. Microstructure and mechanical properties of the samples were investigated and compared before and after irradiation. The irradiation induced an increase in hardness, whereas a decrease in Young’s modulus was observed for both samples. Microstructural characterization revealed irradiation-induced cracking, initiated in the bulk of the material, where the peak damage was deposited, propagating towards the surface. Additionally, transmission electron microscopy was used to study irradiation defects. Dislocation loops and fringes were identified and observed to increase in density with increasing dose levels. The high density of irradiation defects is proposed as the main cause of swelling and consequent sample cracking, leading simultaneously to increased hardening and a decrease in Young’s modulus.

中文翻译：

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UN 和 (U,Zr)N 复合燃料中质子辐照引起的裂纹和微观结构缺陷


使用 2 MeV 一次离子能量的质子辐照来模拟 UN 和 (U,Zr)N 燃料芯块的辐射损伤。标称在室温下的颗粒被辐照至 0.1、1、10 dpa 和 100 dpa 的峰值水平，从而产生至多 1 at 的峰值氢浓度。 %。研究并比较了辐照前后样品的显微组织和力学性能。辐射导致两个样品的硬度增加，而杨氏模量下降。微观结构特征表明，辐照引起的裂纹始于材料的大部分，其中沉积了峰值损伤，并向表面传播。此外，还使用透射电子显微镜来研究辐照缺陷。识别并观察到位错环和条纹的密度随着剂量水平的增加而增加。高密度的辐照缺陷被认为是膨胀和随后的样品开裂的主要原因，同时导致硬化增加和杨氏模量降低。