氚废气的回收技术研究

INVESTIGATION ON CLEANUP OF GAS CONTAINING TRITIU M

采用了高温催化氧化法处理含氚废气。处理过程如下:在干燥氩气(含少量H2)的载带下,含氚废气通过高温催化氧化床转化为氚水,然后用蒸馏水或合适的干燥剂吸收。在400℃,氧化床穿透之前,Hopcalite氧化剂对H2的氧化效率接近100%;在500℃,Hopcalite氧化床对HT的氧化效率大于99%。实验测定了回收氚的分子筛在存放过程中,不同规格分子筛的氚释放系数以及存放条件与释放系数的关系。结果表明,3种分子筛在吸收氚水后的氚释放系数为(1.9～5.5)×10-6d-1·g-1。其中,4A钠型分子筛的氚释放系数最小,5A钙型分子筛的氚释放系数最大;3种分子筛在吸收氚水后释放的氚的化学形式绝大部分是氚化水(HTO),氚气(HT)含量不超过1.2%;含氚分子筛的贮存气氛对氚的再释放有一定影响,在纯氩气中氚释放系数比在含2%氢的氩气中的低。

Tritium in off-gas is oxidated to tritium water by catalyzer at high temperature in a dry carrier Argon gas with a little hydrogen, and is adsorbed by distilled water or suitable dryer. Oxidation rate of catalyzer for H 2 and HT is near 100% at 400 ℃ and more that 99% at 500 ℃, respeclively. Tritium release rate from three types molecular seives which adsorbed tritium water is found to be about (1.9～5.5)×10 -6 d -1 ·g -1 , the smallest one is for 4A-Na-type molecular seive and the largest one is for 5A-Ca-type molecular seive. The chemical state of released tritium from three types molecular seives is mainly in the form of HTO, and content of HT is less than 1.2%. Storage atmosphere of tritide molecular sevies greatly affects the tritium release. Release rate of tritium in pure argon gas is less than that in argon gas with 2% hydrogen.