建立了一种测定UO_2-Gd_2O_3烧结芯块氧与金属原子比(简称O/M比)的新方法——分光光度法。以浓磷酸为溶剂,U~(6+)和U~(4+)离子的特征吸收波长分别确定在310nm和544nm。U~(6+)和U~(4+)离子浓度分别由其特征波长的吸光度与相应的标准曲线对比来确定。计算O/M比的公式由物质内部电中性原理导出。实验结果表明,烧结芯块中钆的含量和微观均匀性 A new method for the determination of oxygen to metal atomic ratio (abbreviated as O / M ratio) of UO_2-Gd_2O_3 sintered pellets was established - spectrophotometry. With concentrated phosphoric acid as solvent, the characteristic absorption wavelengths of U ~ (6+) and U ~ (4+) ions were determined at 310nm and 544nm, respectively. The concentration of U ~ (6+) and U ~ (4 +) ions were determined by comparing the absorbance at their characteristic wavelength with the corresponding standard curve. The formula for calculating the O / M ratio is derived from the internal neutral principle of matter. The experimental results show that the content and the uniformity of gadolinium in the sintered pellets