UO2-不锈钢燃料棒的光纤激光切割研究

为验证光纤激光用于燃料组件解体和燃料棒切割的可行性，研究光纤激光用于热物性差别很大的UO2芯块 不锈钢包壳管复合结构的切割和铀芯块的切割质量，本文采用光纤激光切割UO2芯块 316Ti包壳管元件棒，并通过扫描电子显微镜、能谱和X射线衍射对UO2芯块的切断面进行微观表征分析，研究激光切割过程对铀芯块切断的表面微观形貌、元素组成及物相的影响。研究结果表明，光纤激光可用于切割UO2芯块 316Ti包壳管元件棒，激光切割过程虽会造成铀芯块切断面出现大量微孔和碎渣，但不会造成UO2的相变。以上结果表明，光纤激光可用于UO2芯块 316Ti包壳管元件棒的切割，通过后续对激光切割系统的抗辐射屏蔽防护，可应用于乏燃料组件解体和乏燃料棒切割。

Experimental Study on Fiber Laser Cutting of UO2-stainless Steel Fuel Rod

In order to verify the feasibility of using fiber laser for fuel assembly disassembly and fuel rod cutting, the cutting quality of UO2 pellet stainless steel cladding composite structure with great difference in thermal properties and fuel rod pellet cutting quality were studied. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X ray diffraction (XRD) were used to characterize the microstructure of cross section of UO2 pellets. And the effects of laser cutting process on the surface morphology, element composition and phase of uranium pellets were studied. The results show that fiber laser can be used to cut nuclear fuel rod which is composed of UO2 pellets and 316Ti cladding. Although the laser cutting process leads to a lot of micropores and fragments on the cutting section, it doesn’t cause the phase transformation of UO2. This study shows that the fiber laser can be used in the cutting of nuclear fuel rod which is composed of UO2 pellets and 316Ti cladding. Through the subsequent radiation shielding protection of the laser cutting system, the fiber laser can be applied to the spent fuel assembly disassembly and spent fuel rod cutting.