为了准确测量燃料管燃耗和验证燃料管运行的正确性,保证反应堆安全运行、提高燃料的利用率和经济性,针对大直径燃料管相对燃耗测量存在的问题,根据燃料管结构设计了燃料管γ扫描测量系统。首先,用已知活度的10 mm 137Cs标准点源验证了装置的可靠性和方法的可行性。然后,选取了同一燃料组件3种不同直径燃料管进行γ扫描,分别测量了燃料管径向和轴向相对燃耗分布,根据径向相对燃耗分布确定了燃料管阴阳面。最后,在燃料管阳面最大燃耗处进行燃料管轴向γ扫描,获得燃料管轴向相对燃耗分布,并对比各层燃料管相对燃耗大小。通过本方法确定的燃料管相对燃耗测量相对误差小于4%,实现了燃料管相对燃耗的精确测量,为其它类型燃料元件相对燃耗测量提供了一种新思维。
The Cu2S/tetrapod-like ZnO whisker（T-ZnOw） heterostructures were successfully synthesized via a simple polyol process employing the poly（vinyl pyrrolidone）（PVP） as a surfactant.The as-prepared heterostructures were characterized by X-ray diffraction（XRD）,field emission scanning electron microscopy（FESEM）,X-ray photoelectron spectroscopy（XPS） and Fourier transform infrared（FTIR）.The photocatalytic properties of Cu2S/T-ZnOw nanocomposites synthesized with different PVP concentrations were evaluated by photodegradation of methyl orange（MO） under UV irradiation.The results show that the Cu2S/T-ZnOw nanocomposites exhibit remarkable improved photocatalytic property compared with the pure T-ZnOw.The sample prepared with 3.0 g/L PVP shows an excellent photocatalytic property and the highest photodegradation rate of MO is 97% after UV irradiation for 120 min.Besides,the photocatalytic activity of the photocatalyst has no evident decrease even after four cycles,which demonstrates that the Cu2S/T-ZnOw photocatalyst exhibits an excellent photostability.Moreover,the photocatalytic mechanism of the Cu2S/T-ZnOw nanocomposites was also discussed.
