摘要
在熔盐堆核能系统中,为避免载体盐中含氧类杂质离子的腐蚀性及其与UF_(4)燃料反应生成UO_(2)沉淀而造成安全隐患,需严格控制熔盐中的含氧类杂质离子含量。利用自行研制的熔盐减压蒸馏装置,研究了载体盐中主要含氧杂质离子(O^(2−)、NO_(3)^(−)、SO_(4)^(2−)、PO_(4)^(3−))在高温低压下的蒸发分离行为,以及温度、压力、熔盐起始氧含量等工艺参数对载体盐中O^(2−)去除的影响规律。研究结果表明:减压蒸馏法对含氧杂质去除能力由强到弱依次为NO_(3)^(−)、PO_(4)^(3−)、SO_(4)^(2−)、O^(2−);随着温度升高,氧的去除效果增强,1050℃时获得了总氧含量约2.40×10^(−4) g·g^(−1)盐的回收盐;随着压力降低,熔盐蒸发过程中O^(2−)的夹带现象加剧,压力高于40 Pa时可获得总氧含量为2.50×10^(−4) g·g^(−1)盐的回收盐;随起始含量降低,回收盐中氧含量持续降低,证实了二次或多次蒸馏熔盐除氧的技术可行性。本研究表明减压蒸馏法可有效去除载体盐中的含氧类杂质离子,实现载体盐的快速、高效纯化。
[Background]In molten salt reactor,the concentration of oxygen impurities in the molten salt should be strictly controlled to avoid the potential safety risks caused by the reaction of O^(2−) in the carrier salt with UF_(4) fuel to generated UO_(2) precipitation.[Purpose]This study aims to investigate the evaporation behavior of the main oxygen containing impuritiy ions in carrier salt at high temperature and low pressure and the influence of process parameters such as temperature,pressure and initial oxygen content of molten salt on the removal of O^(2−) in carrier salt.[Methods]The vacuum distillation method was employed and a vacuum distillation device were used to carried out experimental study of the separation behavior of the main oxygen-containing impurities NO_(3)^(−),SO_(4)^(2−),PO_(4)^(3−) and O^(2−) in the carrier salt during vacuum distillation.The removal mechanism of the above ions was explored,and the specific influence of process conditions on the separation effect of O^(2−) distillation was investigated.[Results]The results show that the removal ability of oxygen-containing impurities by vacuum distillation is NO_(3)^(−)>PO_(4)^(3−)>SO_(4)^(2−)>O^(2−).The removal capacity of O^(2−) increases with the increase of temperature,and the recovered salt with a total oxygen content about 2.40×10^(−4) g·g^(−1) salt is obtained at 1050℃.The phenomenon of oxygen with a total oxygen content about 2.50×10^(−4) g·g^(−1) salt is observed when the pressure is higher than 40 Pa.The oxygen entrainment is increased during the evaporation of molten salt with the decrease of pressure,and the recovered salt content in the recovered salt continued to decrease with the decrease of the initial content of O^(2−) in the carrier salt,which confirmed the technical feasibility of melting salt multiple distillation to remove oxygen.[Conclusions]It is verified by study shows that vacuum distillation can remove oxygen-containing impurities from carrier salt effectively and achieve the rapid and efficient purification of the carrier salt.
作者
郑小强
窦强
程明
李晴暖
付海英
李文新
严六明
ZHENG Xiaoqiang;DOU Qiang;CHENG Ming;LI Qingnuan;FU Haiying;LI Wenxin;YAN Liuming(College of Sciences,Shanghai University,Shanghai 200444,China;Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《核技术》
CAS
CSCD
北大核心
2022年第4期44-50,共7页
Nuclear Techniques
基金
中国科学院战略性科技先导专项(No.XDA0230000)
国家自然科学基金(No.21771188)资助。
关键词
熔盐堆
载体盐
减压蒸馏
氧去除
Molten salt reactor
Carrier salt
Vacuum distillation
Removal of oxide
