催化氧化-液闪法测量氢气中低水平氚浓度  

Quantitative detection of tiny amounts of tritium in hydrogen using thecatalytic oxidation-liquid scintillation counting method

作　　者：武超 张宾永 任英[1] 刘艳[1] 李乐斌[1] WU Chao;ZHANG Binyong;REN Ying;LIU Yan;LI Lebin(China Institute of Atomic Energy,Beijing 102413 China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《中国辐射卫生》2024年第3期267-272,共6页Chinese Journal of Radiological Health

摘　　要：目的建立低于气体同位素质谱仪检测限的氢气中低水平氚浓度的测量方法。方法通过自研的催化氧化装置利用铂疏水催化剂将氢气合成为水,并考察不同实验条件对氢气转化率的影响;然后用液闪分析方法对合成水中的氚浓度进行分析;最后根据合成水的测量结果推算出氢气中的氚浓度。结果固定氢气流量,氢气转化率随反应温度的升高而升高、随氧气流量的增大先升高后减小,经条件优化,氢气可完全转化。在反应温度110℃、氧氢流量100 mL/min条件下,将HT体积分数在(1×10^(-7)~2×10^(-14))范围内的氢气合成为水并用液闪测量,测量精度优于2%。结论该方法可以用于HT含量低于同位素质谱仪检测限的氢气中氚浓度的测量,为低温精馏工艺分离能力的计算提供数据支撑。Objective To establish a method for quantitative analysis of tiny amounts of tritium in hydrogen below the detection limit of isotope ratio mass spectrometer.Methods Hydrogen was oxidized to produce water in a self-developed catalytic oxidation device filled with platinum hydrophobic catalyst.The effects of different experimental conditions on hydrogen conversion rate were investigated.The tritium concentration in the synthetic water was measured using a liquid scintillation counter.The tritium concentration in hydrogen was calculated according to the measurement of the synthetic water.Results When the flow rate of hydrogen was fixed,the conversion rate of hydrogen increased with the increase of the reaction temperature but increased and then decreased with the increase of the flow rate of oxygen.Hydrogen could be completely converted under optimal experimental conditions.The hydrogen samples with volumetric tritium concentrations in the range of 1×10^(-7) to 2×10^(-14) were converted to water at the reaction temperature of 110℃and hydrogen/oxygen flow rate of 100 mL/min.The resulting water was measured using a liquid scintillation counter.The measurement accuracy was better than 2%.Conclusion This method can be used to measure hydrogen samples with tiny amounts of tritium below the detection limit of isotope ratio mass spectrometer.Our results provide data support for the calculation of the separation capacity of cryogenic distillation process.

关 键 词：氢气 催化氧化 氚浓度 液闪 

分 类 号：R144[医药卫生—公共卫生与预防医学]