冠醚萃取法从高放废液中去除锶─—工艺流程的研究

报道了用二环己基１８冠６（ＤＣ１８Ｃ６）－正辛醇萃取法从模拟高放废液中去除锶的研究。从高放废液中去除半衰期较长的９０Ｓｒ，对于高放废液安全处置有着重要意义。系统地研究了ＤＣ１８Ｃ６－正辛醇对Ｓｒ２＋以及废液中其它阳离子Ｎａ＋、Ｋ＋、Ｃｓ＋、Ｎｉ２＋、Ｆｅ３＋、Ａｌ３＋、Ｍｏ（Ⅵ）的萃取性能。结果表明，ＤＣ１８Ｃ６对Ｓｒ２＋有着良好的萃取选择性，除Ｋ＋和Ｍｏ（Ⅵ）等个别离子外，其它阳离子几乎都不被萃取。在此基础上，建立了用ＤＣ１８Ｃ６－正辛醇从高放浓缩废液中去除锶的工艺流程，并进行了模拟料液的串级实验。经过三级萃取，一级洗涤，四级反萃后，锶的去除率接近９９％，产品中锶的重量百分比为７６％（原始料液中为０．６％）。该流程具有简单、高去除率、高选择性、适用料液酸度范围较宽等优点，可望用于从我国高放浓缩废液中去除或回收锶。     

Hydroceramics,a "new" cementitious waste form material for U.S. defense-type reprocessing waste

A "hydroceramic" (HC) is a concrete which possesses mineralogy similar to the zeolitized rock indigenous to the USA's current "basis" high level radioactive waste (HLW) repository site, Yucca Mountain (YM). It is made by curing a mixture of inorganic waste, calcined clay, vermiculite, Na₂S, NaOH, plus water under hydrothermal conditions. The product differs from conventional Portland cement and/or slag-based concretes ("grouts") in that it is primarily comprised of alkali aluminosilicate "cage minerals" (cancrinites, sodalites, and zeolites)rather than hydrated calcium silicates (C-S-H in cement-chemistry shorthand). Consequently it microencapsulates individual salt molecules thereby rendering them less leachable than they are from conventional grouts. A fundamental difference between the formulations of HCs and radwaste-type glasses is that the latter contain insufficient aluminum to form insoluble minerals with all of the alkali metals in them. This means that the imposition of worst-case "repository failure" (hydrothermal) conditions would cause a substantial fraction of such glasses to alter to water-soluble forms. Since the same conditions tend to reduce the solubility of HC concretes, they constitute a more rugged immobilization sub-system. This paper compares leach characteristics of HCs with those of radwaste-type glasses and points out why hydroceramic solidification makes more sense than vitrification for US defense-type reprocessing waste. Electronic Publication     

Synthesis of SrTiO3 for immobilization of simulated HLW by SHS

Strontium titanate synroc samples were synthesized by self-propagating high-temperature synthesis （SHS）. Sr directly took part in the synthesis process. As a result, the loading content issue is basically resolved. The products were characterized by density, microhardness X-ray diffraction, and scanning electron microscopy （SEM/EDS）. The leaching rate was measured by the method of PCT （product consistency test）. The results indicate that the Sr^2＋-SrTiO3 compound is of high density, low leach rate and high stability and the synthesis process is feasible in technology and economy. It can be concluded that the strontium titanate synroc is a perfect material to immobilize HLW.     

地下实验室--高放废物地质处置的重要研究设施

本文介绍了地下实验室的分类和国际发展现状、它在建设高放废物、长寿命核素废物地质处置库中的重要作用、它的建设和运行投资，最后还对我国的地下实验室的开发研究活动提出了建议意见。     

高放废物的处理处置方法

介绍了高放废物处理处置方法，比较了其各自的优缺点，指出深地质处置是处置高放废物的合适方法。     

Design and validation of the THMC China-Mock-Up test on buffer material for HLW disposal

According to the preliminary concept of the high-level radioactive waste （HLW） repository in China, a large-scale mock-up facility, named China-Mock-Up was constructed in the laboratory of Beijing Research Institute of Uranium Geology （BRIUG）. A heater, which simulates a container of radioactive waste, is placed inside the compacted Gaomiaozi （GMZ）-Na-bentonite blocks and pellets. Water inflow through the barrier from its outer surface is used to simulate the intake of groundwater. The numbers of water injection pipes, injection pressure and the insulation layer were determined based on the nu- merical modeling simulations. The current experimental data of the facility are herein analyzed. The experiment is intended to evaluate the thermo-hydro-mechano-chemical （THMC） processes occurring in the compacted bentonite-buffer during the early stage of HLW disposal and to provide a reliable database for numerical modeling and further investigation of engineered barrier system （EBS）, and the design of HLW repository.     

高放废物地质处置的安全评价模拟研究：以甘肃北山为例

高放废物安全处置是全球放射性废物管理的重难点问题之一。目前全球拥有核工业的国家正在积极探索安全处置高放废物的前沿课题,但至今尚无高放废物处置库投入运行。我国北山高放废物地质处置地下实验室即将开工建设,因此亟需开展相关安全评价研究,为今后处置库安全评价打下良好基础。本文论述了高放废物地质处置库安全评价的特性,并以处置库首选预选区甘肃北山为对象,开展了高放废物地质处置安全评价模拟研究,旨在为我国高放废物地质处置安全评价提供建议与参考。本文采用蒙特卡罗随机模拟方法,构建了处置库关闭后的破损情景,对拟贮存60 000个废物罐的处置库关闭后100万年期间的辐射水平进行了模拟计算。研究结果表明,甘肃北山处置库100万年内的高放废物有效剂量均低于国际要求的剂量限值,表明该处置库符合高放废物地质处置库的安全要求。本文对于我国甘肃北山高放废物地质处置安全评价的进一步研究具有重要意义。     

Ca^(2+)盐溶液在高庙子膨润土中的扩散研究北大核心CSCD

高放废物地质处置库近场地下水可能会对处置库内的屏障体系产生影响,降低处置库的安全稳定。为研究地下水中盐离子在处置库内缓冲回填体系的扩散规律,本文开展了静态无外荷载条件下内蒙古高庙子(GMZ)膨润土在Ca^(2+)盐溶液中自发渗吸的吸附扩散室内试验。从土的微观结构和经典扩散理论对Ca^(2+)在不同干密度和初始饱和度的膨润土试样中的自发扩散规律进行了分析。研究结果表明,在膨润土初始饱和度相同的情况下,试样阻滞系数随其干密度增加而增大,此时Ca^(2+)的扩散能力减弱;当膨润土干密度相同时,随着初始饱和度的增加基质吸力作用减弱,阻滞系数减小,Ca^(2+)的扩散能力减弱。     

模拟锶铯废物铁磷酸盐玻璃固化及化学稳定性

研究了铁磷酸盐玻璃固化我国高放废液全分离流程中产出的锶废物及铯废物，熔制了相应的固化体。用XRD，IR测试了固化体的微观结构，用产品一致性试验方法(PCT)研究固化体的化学稳定性。研究表明：在所选的废物包容量范围内可熔制得均质模拟废物铁磷酸盐玻璃固化体，玻璃的主要结构基团为P2O7^4-，均质玻璃固化体有较好的化学稳定性。     

燃烧合成固化高放射性废物

采用燃烧合成技术（CS）制备了包容高放射性废物的钙钛矿陶瓷固化体，测定了其物理性能。采用PCT，X射线衍射（XRD）、透射电镜分析了固化体的浸出率、微观结构和相组分。试验结果表明：该方法可获得较高的反应温度，可使反应在瞬间完成，而且获得的产物具有密度高、成分均匀、浸出率低、包容量大等优点，从而达到封闭、隔离高放废物的目的。