放射性氩气中一氧化碳和甲烷的分析

Analysis of Carbon Monoxide and Methane in Radioactive Argon

以1∶1模拟了正在建造的中国实验快堆的气体回路,建立了一个放射性氩气取样系统以及氩气中杂质CO和CH4的间断性在线分析方法。通过热导检测器使出口气体可以排放入通风系统,避免了使用氢火焰离子化检测器以后,放射性氩气扩散排放到气体分析实验室产生工作环境的放射性污染问题。分析下限(φ)为5×10-6,精密度好于3%,与标准值相差±5%。方法能满足中国实验快堆规定的氩气中杂质CO和CH4的分析要求。

A gas loop that is being constructed in the Chinese Experimental Fast Reactor （CEFR） is simulated in a full scale. A sampling system and a feasible method are developed to realize a discontinuous on-line analysis for carbon monoxide and Methane in argon cover gas system. By using a thermal conductivity detector in stead of a conventional hydrogen flame ionization detector, the exhaust gas from the outlet is directly discharged to a fume hood, thus eliminating the risk of contamination of the analytical laboratory by radioactivity that would be released in the latter case. The experimental results show that the adopted analytical procedure can meet the requirement of CEFR for routine analysis of CO and CH4 ： its precision is better than 3 %, its accuracy is better than ± 5 % as evidenced by analyzing a set of CO and CH4 references, and its lower limit of measurement is 5× 10^-6.