射线技术在工业领域的应用

射线技术在工业生产中应用的广度和深度不断拓展,世界民用非动力核技术产业的规模已经达到了万亿美元。本文系统地介绍了射线技术在工业领域的应用与发展状况,尤其是我国在工业核仪器仪表、核分析、核测井、无损检测和辐照加工等方面的发展历程、取得的进步及面临的挑战,并提出了发展建议,展望发展趋势。     

核与辐射技术在人类健康领域应用研究的进展--介绍IAEA近期有关活动

概要介绍IAEA近年来组织开展的核与辐射技术在人类健康领域应用研究的进展,主要内容包括核医学、应用辐射生物学与放射治疗、剂量学和医用辐射物理、营养和健康相关环境研究等方面。     

IAEA高水平天然辐射工作场所职业防护条件评估技术委员会会议概况

20 0 1年 5月 7～ 1 1日 ,国际原子能机构 (I-AEA)在维也纳国际会议中心召开了名为“高水平天然辐射工作场所职业防护条件评估技术委员会会议 (Technical Committee Meeting on theAssessment of Occupational Protection Condi-tions in Work Places with High Levels of Expo-sure to Natural Radiation)”。来自比利时、巴西、加拿大、中国、芬兰、德国、印度、爱尔兰、意大利、荷兰、挪威、波兰、斯洛伐克、南非、西班牙和瑞典1 6个国家的 2 3名专家参加了这次重要会议。1　会议背景及目的联合国原子辐射效应科学委员会 (UN-SC…     

钚的利用与核裂变能的可持续发展

简要分析了当今世界的能源结构 ,指出以化石燃料为主的能源供应不可持续。概述了乏燃料后处理与钚的循环对充分利用铀资源的贡献 ,指出钚和其他锕系元素的彻底焚烧 ,有可能最大限度地减少放射性废物量及其毒性 ,从而实现核裂变能的可持续发展     

热表面电离质谱法测定钚氧化物中的钚同位素组成

采用热表面电离质谱法对钚氧化物中钚同位素丰度进行了测定。通过对钚氧化物样品预处理、离子源和分析器的真空控制、法拉第杯接收效率检测、测量过程中的信号强度大小控制、信号强度稳定性控制以及测量时间的控制等条件进行优化,确定了最佳预处理条件和测量条件,实现了钚氧化物中钚同位素组分的准确测定。在选定的条件下,测定了钚标准样品中的钚同位素丰度,主同位素239Pu和242Pu测量精密度(sr)均优于0.05%(n=6)。     

Carbothermic Synthesis of High Purity Plutonium Nitride from Plutonium Oxide

Synthetic conditions of PuN from carbothermic reduction of PuO₂ has been studied in a mixed 8%H₂+92%N₂ stream at a temperature range of 1,270–1,680°C. In the course of both reactions of the carbothermic synthesis of PuN from PuO₂ and the hydrogenation of C, the vaporization loss of Pu was observed. It increased with temperature in the temperature range of 1,350–1,450°C, and reached to a constant value 1.3% of total Pu in the temperature range of 1,450–1,680°C, at which PuN was synthesized at a reaction rate of high enough. The minimum mixing ratio (C/PuO₂, mole ratio) for the formation of high purity PuN depends on temperature. The value is 2.15 for 1,620°C and 2.35 for 1,680°C. The oxygen and carbon impurities in the PuN obtained were found to be 0.095–0.028 and 0.17–0.012w/0, respectively.     

Evaluation of Proliferation Resistance of Plutonium Based on Decay Heat

The present paper is prepared for the peaceful use of nuclear energy. Proliferation resistance of plutonium can be enhanced by increasing the decay heat of plutonium. For example, it can be enhanced by increasing the isotopic fraction of ²³⁸Pu, which has the largest decay heat among plutonium isotopes. In the present paper, the proliferation resistance of plutonium was evaluated based on decay heat with a physical assessment model. New criteria were proposed to evaluate the proliferation resistance based on isotopic compositions of plutonium from the viewpoint of decay heat. The present criteria were applied to evaluate the proliferation resistance of plutonium produced in typical Light Water Reactor and Fast Breeder Reactor based on an evaluation function “Attractiveness” as case studies.     

钚在粘土中的迁移实验

为了获取²³⁹Pu在粘土中的迁移规律,采用静态法和动态柱法实验对其在粘土的迁移进行了研究。结果表明,粘土对²³⁹Pu的吸附能力较强。在实际水流速为0.61cm/d条件下,²³⁹Pu经过150 d迁移距离小于0.2cm。与动态实验相比,采用分配系数计算延迟系数偏小,动态实验结果更接近实际。     

Temperature Effect on Plutonium Leach Rate of Nuclear Waste Glass

The two kinds of nuclear waste glass with similar composition, a ²³⁸Pu-doped and nonradioactive waste glass, were leached under the ISO-test conditions at temperature between 23 and 90°C. An activation energy of 22±10kJ/mole was obtained from the initial leach rates of Pu, which was much lower than the 78±9kJ/mole obtained from those of Si, Na, Sr and Cs, It is suggested that in the initial stages of leaching. Pu is not released from the waste glass with the same mechanisms as the releases of Si, Na, Sr and Cs, but the dissolution of hydrous plutonium dioxide PuO₂·_xH₂O formed on the glass surface becomes predominant. In the long duration tests (<32d), the release of Pu appears to be affected by the solubility of PuO₂·_xH₂O remaining in the leached surface layers.     

Management of Plutonium Content based on Reactivity of Each Plutonium Isotope

It is strongly demanded to control reactivity for safety and steady operation of nuclear reactor. Fissile enrichment should be, therefore, accurately managed in order to carry out it. A concept of physical accounting method for adjusting fissile enrichment is very useful to manage plutonium content and to control reactivity of nuclear reactor where plutonium is used as main fissile material. The basis of the concept is shown in this paper together with the result of the application to typical prototype fast breeder reactor (FBR). The rationality for adopting the method is also quantitatively shown in this paper.     

铀、钚氧化物氯化溶解技术进展

氧化物的溶解过程是氧化物乏燃料熔盐电解干法后处理工艺的关键步骤,溶解产物将为后续铀钚的分离回收提供原料。氧化物在熔盐体系中溶解度和溶解速率一般较小,为满足工艺需要,通常需要引入氯化试剂。使用不同的氯化试剂,其溶解机理有较大差异。通过广泛的文献调研,分析比较了各种氯化试剂在氯化过程中相关原理及特点,为我国开展铀、钚氧化物氯化溶解的研究提供指导。     

气体采样滤膜中钚的激光诱导击穿光谱定量分析研究

在核设施排放物的监测中,为确保环境安全及实现核材料衡算,需针对通风管气体采样滤膜中钚的含量进行分析。为探索利用激光诱导击穿光谱（LIBS）技术定量分析滤膜中钚元素含量的可行性,开展了某核设施热室内含钚气体采样滤膜的LIBS分析研究。通过分析含钚气体采样滤膜中钚的LIBS特征光谱信号,筛选出钚的有效发射谱线,并优化LIBS测量延迟时间参数,最终得到了浓度范围较低情况下的定量标准曲线,并进行了技术验证分析。研究结果显示,针对滤膜中的钚元素可采用有效特征谱线进行LIBS定量分析,能用于定量分析钚的可分析有效特征谱线为PuⅡ 443.298 nm、PuⅠ 460.721 nm、PuⅡ 466.389 nm。分析结果表明,LIBS分析结果的精度好于3%。     

Preparation of Uranium and Plutonium Metals

A new process for preparing uranium and plutonium metals has been developed. The process is based on the high extractability of the elements with sodium amalgam from aqueous solutions. After extracting the uranium or plutonium with sodium amalgam, the resulting amalgam was heated in vacuum so that mercury and sodium were separated to produce uranium or plutonium metal. The mercury and sodium remaining in the uranium metal thus produced were found to be less than 5 and 15 ppm, respectively. The proposed process for preparing uranium and plutonium metals is applicable to other actinoids extracted with sodium amalgam from aqueous solutions.