PUREX流程中铀/钚分离用四价铀还原剂的制备  

Preparation of U(Ⅳ) as Reducing Agent for Uranium/Plutonium Separation in PUREX Process

作　　者：宋淼 王博 张宝钢 胡彦涛 张晓腾 蔡梦琦 纪雷鸣 侯宝林[2] SONG Miao;WANG Bo;ZHANG Bao-gang;HU Yan-tao;ZHANG Xiao-teng;CAI Meng-qi;JI Lei-ming;HOU Bao-lin(China Nuclear Power Engineering Co.,Ltd.,Beijing 100840,China;Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian Liaoning 116023,China)

机构地区：[1]中国核电工程有限公司,北京100840 [2]中国科学院大连化学物理研究所,辽宁大连116023

出　　处：《当代化工》2023年第3期559-564,共6页Contemporary Chemical Industry

基　　金：中核集团青年英才(菁英)项目(项目编号:NO.CNPE-KY21142)。

摘　　要：源于不向系统引入新的固体无机盐杂质,四价铀作为铀/钚分离的最佳还原剂得到了广泛的应用。目前,从硝酸铀酰还原制备四价铀的生产工艺有电解法、硝酸肼催化还原法和氢催化还原法。首先从热力学的角度论证了各工艺过程中所涉及的主反应与副反应,并结合工艺操作参数对比了各工艺过程。对比结果显示:电解法技术成熟、廉价可靠,但是转化率相对较低,需要后续开发新的电极材料及长寿命离子膜;硝酸肼催化还原法制备四价铀的工艺具有操作条件温和、产量大的优点,但是要求的原料纯度高,副反应严重且复杂;氢催化还原法已经在法国实现工程应用多年,具有成本低、产量高、反应速度快、副反应少的优点。因此,建议通过借鉴一般化工工业中氢气安全使用经验,在我国后处理厂中使用氢催化还原法制备四价铀工艺,并使用滴流床反应器,提高气液固接触效率,突破四价铀产能和产物浓度的瓶颈,满足使用需求。Tetravalent uranium(U(Ⅳ))is the most widely used reducing agent for uranium-plutonium separation in PUREX process,since no new inorganic salt is introduced into the system.At present,the synthesis processes of U(Ⅳ)from U(Ⅵ)mainly include electrolysis reduction,catalytic reduction with hydrazine nitrate,catalytic reduction with hydrogen.In this paper,the main reactions and side reactions involved in each process were firstly demonstrated from the perspective of thermodynamics,and all processes were compared from the aspects of operation parameters.The comparison results show that the electrolysis reduction process has the advantages of mature technology,cheap and reliable,but the conversion is relatively low,so it is necessary to develop new electrode materials and long life ion film.The catalytic reduction with hydrazine nitrate process has the advantages of mild operating conditions and large yield,but it requires high purity of hydrazine nitrate,and the side reactions are also serious and complex.The catalytic reduction with hydrogen process has been applied in France for many years.It has the advantages of low cost,high yield,fast reaction and less side reaction.Therefore,catalytic reduction with hydrogen process is preferred to synthesize U(Ⅳ)in reprocessing plants by referring to the safe use experience of hydrogen in general chemical industry,and trickle bed reactor is suggested to break through the capacity and concentration bottleneck of U(Ⅳ)preparation to meet the needs.

关 键 词：四价铀 铀钚分离 电解还原 催化肼还原 催化氢还原 

分 类 号：TL241.1[核科学技术—核燃料循环与材料]