PUREX流程中锝对U(Ⅳ)-肼的稳定性影响  

Effect of Technetium on Stability of U(Ⅳ)and Hydrazine in PUREX Process

作　　者：刘金平[1] 何辉[1] 黄小红[1] 叶国安[1] 王辉[1] 晏太红[1] 李斌[1] 贾永芬[1] LIU Jin-ping;HE Hui;HUANG Xiao-hong;YE Guo-an;WANG Hui;YAN Tai-hong;LI Bin;JIA Yong-fen(China Institute of Atomic Energy, P. O. Box 275(26), Beijing 102413, China)

机构地区：[1]中国原子能科学研究院放射化学研究所,北京102413

出　　处：《核化学与放射化学》2018年第6期366-372,共7页Journal of Nuclear and Radiochemistry

基　　金：国家自然科学基金资助项目(21790371)

摘　　要：通过分光光度法研究了硝酸体系中锝催化硝酸氧化U(Ⅳ)-肼的反应,结果表明:温度和锝浓度是影响锝催化硝酸氧化U(Ⅳ)速率的主要因素,Tc催化硝酸氧化U(Ⅳ)反应对Tc的级数为1.23,反应活化能Ea=79.2kJ/mol,Tc催化硝酸氧化U(Ⅳ)反应对U(Ⅳ)的级数为0,平均速率常数为1.60×10-4 min-1。肼浓度对锝催化氧化U(Ⅳ)的速率影响较小,Tc-U(Ⅳ)-肼体系中肼的氧化和U(Ⅳ)的氧化同时进行,但U(Ⅳ)早于肼氧化完,随后肼快速氧化完全,与Tc-肼体系相比,肼的氧化速率略有降低,U(Ⅳ)对肼的氧化既有促进作用,又有抑制作用。Tc-U(Ⅳ)-Pu(Ⅲ)-肼体系中,当锝浓度为0.005 mol/L,Pu(Ⅲ)稳定存在的时间小于45min。In this research,the oxidation reaction of U(Ⅳ)-hydrazine catalyzed by technetium in nitric acid was studied by spectrophotometry.The results show that temperature and technetium concentration are the main factors affecting the oxidation rate of U(Ⅳ).The reaction order for technetium is1.23,and the reaction activation E a is79.2kJ/mol.A zero-order reaction characteristic for U(Ⅳ)is observed with average reaction rate constant1.60×10-4min-1.The concentration of hydrazine has little effect on the oxidation rate of U(Ⅳ)catalyzed by technetium.In Tc-U(Ⅳ)-hydrazine system,U(Ⅳ)and hydrazine are oxidated simultaneously.At first,U(Ⅳ)is oxidated completely,and subsequently,the hydrazine is oxidated completely soon.Compared to the system of Tc-hydrazine,the oxidation rate of hydrazine containing U(Ⅳ)is a little slower,and U(Ⅳ)shows both acceleration and inhibition impact on oxidation of hydrazine catalyzed by technetium in nitric acid.In Tc-U(Ⅳ)-Pu(Ⅲ)-hydrazine system,Pu(Ⅲ)is stable for less than45min when the concentration of technetium is0.005mol/L.

关 键 词：锝 U(Ⅳ) 钚 肼 催化氧化 

分 类 号：TL241.1[核科学技术—核燃料循环与材料]