高放废液中锕系离子分离研究进展 Ⅰ.双酰胺荚醚与锕系离子的配位化学

如何处理处置核电站反应堆产生的乏燃料及乏燃料后处理过程产生的高放废液是发展安全核能面临的一个主要问题。为提高核能的安全性、减少需要长时间深地层处置的高放废物量、有效利用地球上有限的可裂变材料资源,世界上发展核能的国家在过去几十年发展了从高放废液中分离少量锕系元素离子的萃取分离流程。近年来,双酰胺荚醚类化合物在锕系元素分离方面备受关注,本文从基础配位化学角度综述近期这类化合物与锕系元素离子相互作用等方面的研究结果。     

高放废物处置的几个问题

就与高放废物处置有关的几个问题,如地下实验室进行场所问题,地下实验室与处置库建设安排问题,高放废物深地质处置的替代方法等进行了探讨,希望有助于我国高放废物处置工作的进一步开展。     

富钙钛锆石的合成

铀钚的高放射性核废料(HLW)的固化是目前一个十分值得关注的课题，人造岩石作为固化基材是一种可行的方法。研究了固相反应法和液相反应法合成钙钛锆石的工艺条件，获得了合成富钙钛锆石较佳的工艺条件。实验结果表明．2种方法均能合成纯度较高的钙钛皓石．可以利用富钙钛皓石作为固化放射性核素U、Pu的固化基材，但是，固相反应法的工艺简单．原料易得且价格较低，合成钙钛皓石的纯度较高，更适合于工程化应用。     

日本JNC瑞浪地下实验室项目研究活动介绍

本文介绍了日本核燃料循环开发研究所（JNC）瑞浪地下实验室（MIU）的研究目标、内容和工作计划，对高放处置的背景作了简要说明。     

缓冲/回填材料——内蒙古高庙子膨润土性能研究

研究按缓冲回填材料的性能要求,对内蒙古高庙子膨润土的物质组成与结构、物理化学性质、水理性质等进行了系统研究;对添加剂改善膨润土的压实性能进行了探索性实验研究。结果表明,高庙子钠基膨润土以蒙脱石为主要矿物成分,具有良好的吸附性、膨胀性、阳离子交换性和热稳定性;石英砂添加剂可以有效地改善膨润土的压实性能;进一步论证了内蒙古高庙子膨润土矿床可以作为我国高放废物地质处置库缓冲/回填材料的供给基地。     

缓冲/回填材料--膨润土研究国际进展

缓冲材料是高放废物地质处置库多重屏障系统重要组成部分。本文从膨润土特性、气体渗透性、膨润土中有机物、微生物腐蚀、孔隙水化学、蒙脱石向伊利石转化、核素迁移等方面简要总结了该领域的一些研究进展，旨在推动我国在这一领域的研究走向深入。目前，国内的工作主要集中于材料物理性能的测试，作者期待国家有关部门能加大经费支持力度。以推动这一领域的研究进展。确保高放废物的安全处置，为能源工业发展保驾护航。     

Isotope dilution inductively coupled plasma mass spectrometry for determination of 126Sn content in spent nuclear fuel sample

The ¹²⁶Sn content in a spent nuclear fuel solution was determined by isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) for its inventory estimation in high-level radioactive waste. A well-characterized irradiated UO₂ fuel sample dissolved in a hot cell was used as a sample to evaluate the reliability of the methodology. Prior to the ICP-MS measurement, Sn was separated from Te (¹²⁶Te), which causes major isobaric interference in the determination of ¹²⁶Sn content, along with highly radioactive coexisting elements, such as Sr (⁹⁰Sr), Y (⁹⁰Y), Cs (¹³⁷Cs) and Ba (^137m Ba), using an anion-exchange column. The absence of counts attributed to Te at m/z = 125, 128, and 130 in the Sn-containing effluent (Sn fraction) indicates that Te was completely removed from the anion-exchange column. After washing, Sn retained on the column was readily eluted with 1 M HNO₃ accompanied with approximately 80% of the Cd and 0.03% of the U in the initial sample. Owing to the presences of Cd and U in Sn fraction, the measurements of ¹¹⁶Sn and ¹¹⁹Sn were affected by the isobaric ¹¹⁶Cd and the doubly charged ²³⁸U²⁺ion, resulting in the positive bias of the determined values. With the exception of the isotopic ratios including ¹¹⁶Sn and ¹¹⁹Sn, ¹¹⁷Sn/¹²⁶Sn, ¹¹⁸Sn/¹²⁶Sn, ¹²⁰Sn/¹²⁶Sn, ¹²²Sn/¹²⁶Sn and ¹²⁴Sn/¹²⁶Sn were successfully determined and showed good agreement with those obtained through ORIGEN2 calculations. The measured concentration of ¹²⁶Sn in the spent nuclear fuel sample solution was 0.74 ± 0.14 ng/g, which corresponds to 23.0 ± 4.5 ng per gram of the irradiated UO₂ fuel (excluding the presence of ¹²⁶Sn in the insoluble residue). The results reported in this paper are the first experimental values of ¹²⁶Sn content and isotope ratios in the spent nuclear fuel solution originating in spent nuclear fuel irradiated at a nuclear power plant in Japan.     

The Beishan underground research laboratory for geological disposal of high-level radioactive waste in China: Planning,site selection,site characterization and in situ tests

With the rapid development of nuclear power in China, the disposal of high-level radioactive waste (HLW) has become an important issue for nuclear safety and environmental protection. Deep geological disposal is internationally accepted as a feasible and safe way to dispose of HLW, and underground research laboratories (URLs) play an important and multi-faceted role in the development of HLW repositories. This paper introduces the overall planning and the latest progress for China's URL. On the basis of the proposed strategy to build an area-specific URL in combination with a comprehensive evaluation of the site selection results obtained during the last 33 years, the Xinchang site in the Beishan area, located in Gansu Province of northwestern China, has been selected as the final site for China's first URL built in granite. In the process of characterizing the Xinchang URL site, a series of investigations, including borehole drilling, geological mapping, geophysical surveying, hydraulic testing and in situ stress measurements, has been conducted. The investigation results indicate that the geological, hydrogeological, engineering geological and geochemical conditions of the Xinchang site are very suitable for URL construction. Meanwhile, to validate and develop construction technologies for the Beishan URL, the Beishan exploration tunnel (BET), which is a 50-m-deep facility in the Jiujing sub-area, has been constructed and several in situ tests, such as drill-and-blast tests, characterization of the excavation damaged zone (EDZ), and long-term deformation monitoring of surrounding rocks, have been performed in the BET. The methodologies and technologies established in the BET will serve for URL construction. According to the achievements of the characterization of the URL site, a preliminary design of the URL with a maximum depth of 560 m is proposed and necessary in situ tests in the URL are planned.     

Numerical analysis of thermal process in the near field around vertical disposal of high-level radioactive waste简

For deep geological disposal of high-level radioactive waste (HLW) in granite, the temperature on the HLW canisters is commonly designed to be lower than 100 °C. This criterion dictates the dimension of the repository. Based on the concept of HLW disposal in vertical boreholes, thermal process in the near field (host rock and buffer) surrounding HLW canisters has been simulated by using different methods. The results are drawn as follows: (a) the initial heat power of HLW canisters is the most important and sensitive parameter for evolution of temperature field; (b) the thermal properties and variations of the host rock, the engineered buffer, and possible gaps between canister and buffer and host rock are the additional key factors governing the heat transformation; (c) the gaps width and the filling by water or air determine the temperature offsets between them.