Spectrometric method of evaluating spent nuclear fuel characteristics

A spectrometric method of identifying spent fuel assemblies according to the type of fuel elements present in them is described. The method is based on the results of spectrometric measurements and subsequent analysis of the radiation from fission products and the characteristic radiation from uranium in the irradiated fuel. The fuel assemblies used in the VVR-2 and OR research reactors contained fuel elements of a different type, differing by the initial quantity of uranium contained in them. To prepare the spent fuel assemblies for shipment to a reprocessing facility after long-time storage in cool-down pools, the assemblies must be sorted according to the type of fuel elements present in them. The method developed for identifying the types of fuel elements in the irradiated fuel is based on the dependence of the intensity of the characteristic radiation from uranium on the uranium content in a fuel element. The degree of excitation of the characteristic radiation of uranium also depends on the intensity of the radiation from fission products, which is monitored during the spectrometric measurements performed on the irradiated fuel; ultimately, this makes it possible to sort the spent fuel assemblies.     

基于还原体系的气溶胶中铀同位素分析方法研究

铀的同位素分析对铀的辐射剂量评价和环境污染源调查工作有重要意义。本文建立了以抗坏血酸为还原剂的气溶胶样品铀同位素分析方法,将气溶胶样品全融处理,离子交换法对铁、钚等干扰元素的去除效果良好,铀同位素的放化回收率为74.5%～93.6%,平均值为81.5%,能够满足气溶胶样品铀同位素常规分析的要求。     

The provision of radiation safety of personnel in the extraction of uranium ores

The radiation hazard to the respiratory organs of miners in uranium mines is assessed and a set of measures is worked out for ensuring radiation safety in the prospecting and extraction of uranium ores. Measures are described and justified which, as a result of achieving them, enable a standard to be set for a mining atmosphere and also to prevent external radiation overexposure and radioactive contamination of the integumenta of people working in the uranium mines.Translated from Atomnaya Énergiya, Vol. 19, No. 2, pp. 161–168, August, 1965     

The effects of irradiation on solids

A short survey is given of the reports on the effects of radiation on solids that were given at the Second International Conference on the Peaceful Use of Atomic Energy (Geneva, 1958). Consideration is given to the experimental work devoted to quantitative estimates of radiation damage, and also to questions of the action of neutron radiation on fissionable materials (uranium, plutonium, and certain alloys of these metals). New data are presented on the effect of very high burnups (up to 2 atom per cent) on the size and shape of units made of uranium and its alloys, and also on the increase of volume (swelling) of uranium units under the action of radiation. Detailed attention is also given to data on studies of uranium alloy with 9 per cent of molybdenum by weight, and also of pure uranium, which give evidence of high mobility of the atoms in uranium and its alloys under irradiation. Data are presented on the effects of temperature and of radiation dosage, and also on a number of other factors, on the mechanical properties of steels and other construction materials. Results are presented from studies of the effects of irradiation on nonmetallic materials: BeO, UO₂-BeO and UO₂ThO₂ mixtures, graphite, and so on.     

铀纯化转化生产过程中作业人员的β外照射防护研究

为了加强铀纯化转化生产过程中作业人员的β外照射防护,结合国内外辐射监测实践,研究了铀纯化转化生产工艺过程中辐射源项的特性及辐射防护措施。由于铀系中主要β发射体²³⁴Th(UX1)、^234mPa(UX2+UZ)、²¹⁴Bi和²¹⁴Pb的存在,铀化合物中的β辐射强度相当可观。在无防护措施的情况下,尤其是在进行开放式检修作业时,作业人员眼晶体、手部和皮肤的β受照剂量可能超过规定限值。因此,除了关注γ外照射和吸入内照射防护外,对作业人员β外照射的防护应该引起足够的重视。     

含铀氢氟酸再利用辐射影响研究

为解决核设施运行产生副产品含铀氢氟酸的处理问题,本文对我国核燃料元件生产线运行产生的含铀氢氟酸用于生产氟化氢铵的辐射影响进行了分析。结果表明,铀含量小于0.2 mg/L的氢氟酸用于生产氟化氢铵过程中对工作人员所造成的附加剂量远低于1 mSv/a,产品氟化氢铵中的铀含量小于1 Bq/g。从辐射影响角度分析,含铀氢氟酸用于氟化氢铵生产是完全可行的,有利于实现放射性废物最小化和资源利用。     

关于铀的摄入量限值

本文阐述了铀的特性,讨论了天然铀的摄入量限值和导出空气浓度,以及它们在制定辐射防护标准中的应用问题。     

中国核工业30年过量受照人员临床案例选编(英文)

选编了三十多年来,核工业生产中部分过量受照人员的剂量估算、实验室检查、诊断、治疗及医学随访观察的临床案例。介绍了核工业系统中在防治内照射辐射损伤、皮肤放射损伤及小剂量外照射辐射效应等方面的临床实践经验。     

用远红外线干燥氧化铀凝胶球

研究了用远红外线干燥氧化铀凝胶球的各种影响因素，其中包括湿球（φ１．２ｍｍ）的铺放强度。空气的对流与增湿，温控程序等。目的是获得无破裂的干球，以奠定热处理的良好基础。结果表明：远红外箱内的热空气应当对流与增湿。在温控程序中对６Ｏ℃的恒温时间应≥２．５ｈ，在该条件下，湿球的铺放强度能达到３．８ｋｇ／ｍ２。还讨论了凝胶结构、脱水及干球破裂的机理。     

环境放射性测评工作--以蒙古和罗马尼亚为例

由于人类非常态活动，导致环境放射性异常变化。蒙古是世界第二大内陆国，铀资源殷实，煤电是主要能源；罗马尼亚为欧洲内陆国家，平均每1万平方公里的国土面积里就拥有一个铀矿床。由于历史原因，两国铀工业活动较活跃。近年来，两国十分关注环境问题，先后对建筑材料的放射性、室内外空气中的氡等实施调查和研究。本文介绍了蒙古和罗马尼亚两国环境放射性的基本态势，以及环境放射性调查方法等。两国环境放射性调查的结果表明：由于蒙古特殊的地理、政治、工业环境。导致其少数地区河水中的铀偏高(61～985μg／L)，部分土壤中的^137Cs也有增高现象，少量花岗岩石材的放射性核素含量较高。罗马尼亚工业废渣制成的建材放射性核素含量也很高(与其欧洲邻国相比较)，今后拟慎用。蒙古和罗马尼亚两国环境放射性调查的实践与经验对我国类似的工作具有借鉴意义。     

铀矿脉中石英热释光异常现象初析

报道了铀矿脉中石英热释光强度随放射性元素含量增加而降低的异常现象。从高能辐射作用于物体时的两种效应入手，分析讨论了异致热释光强度降低的原因。石英热释光的发光曲线特征揭示了铀矿脉形成的热历史。根据铀、钍、钾含量，计算了铀矿脉中岩矿石的放射生热率，并讨论了石英热释光强度与放射生热率的关系。     

Analysis of the Possibility of Using Fuel Based on Reclaimed Uranium in VVÉR Reactors

A current problem is to show that reclaimed uranium can be, in principle, brought into the VVÉR fuel cycle. The possibility of using fuel based on reprocessed uranium in VVÉR is analyzed. The requirements for the initial isotopic composition of test batches of fuel pellets with 4% effective enrichment are determined, the compensation coefficient is calculated, the requirements for monitoring the isotopic composition are determined, and the technlogy for fabricating fuel pellets from relaimed fuel is determined. It is shown that the basic neutron-physical characteristics satisfy the restrictions adopted in the VVÉR-440 and -1000 designs. The effect of radiation on the public and the environment as a result of switching to fuel fabricated from reclaimed uranium is the same as for the standard oxide fuel.     

基于缓发γ能谱测量的铀丰度分析

本文以加速器驱动的脉冲中子源为照射源、铀材料为照射对象、HPGe探测器为主要探测器,测量得到了铀材料的缓发γ实验谱,再根据理论计算程序和蒙特卡罗方法得到了缓发γ计算谱。结果显示,实验谱和计算谱吻合较好,表明缓发γ能谱测量可作为铀丰度分析的一种技术手段。     

Total reflection X-ray spectroscopy as a rapid analytical method for uranium determination in drainage water

Uranium concentrations in drainage water are typically determined by α-spectrometry. However, due to the low specific radioactivity of uranium, the evaporation of large volumes of drainage water, followed by several hours of measurements, is required. Thus, the development of a rapid and simple detection method for uranium in drainage water would enhance the operation efficiency of radiation control workers. We herein propose a novel methodology based on total reflection X-ray fluorescence (TXRF) for the measurement of uranium in contaminated water. TXRF is a particularly desirable method for the rapid and simple evaluation of uranium in contaminated water, as chemical pretreatment of the sample solution is not necessary, measurement times are typically several seconds, and the required sample volume is low. We herein employed sample solutions containing several different concentrations of uranyl acetate with yttrium as an internal standard. The solutions were placed onto sample holders, and were dried prior to TXRF measurements. The relative intensity, otherwise defined as the net intensity ratio of the Lα peak of uranium to the Kα peak of yttrium, was directly proportional to the uranium concentration. Using this method, a TXRF detection limit for uranium in contaminated water of 0.30 µg/g was achieved.     

Absorption of optical radiation by nanoclusters of sputtered metallic uranium and its oxides

Thin films of uranium-containing materials are used as energy-releasing elements in nuclear-pumped lasers. They serve as a source of fission products which ionize and excite the gaseous medium. In this pumping method, a uranium layer is sputtered by its own fission products. This is one of the factors that limit the service life of energy-releasing elements. The products of sputtering can enter the gas and affect the optical and kinetic properties of laser media. In the present work, calculations are performed of the electrodynamic cross-sections for photoabsorption of optical radiation by nanoparticles of metallic uranium and its oxides. The main space-time relaxation parameters are determined. The effect of sputtered uranium-containing nanoparticles on the absorption of optical radiation in a laser element is evaluated. __________ Translated from Atomnaya énergiya, Vol. 103, No. 2, pp. 98–102, August, 2007.     

铀矿通风防护最优化初探

根据辐射防护三原则，提出了铀矿山通风的目标函数、约束函数和限值方程，对铀矿通风防护最优化方法进行了初探。认为氡渗流控制是实现通风防护最优化的重要途径。     

我国干旱地区放射性废(矿)石治理效果研究

过去50 a的铀矿地质勘查为我国核工业发展提供了所需的铀矿资源,同时也产生了大量不同水平的放射性废(矿)石。从1990年开始,中国核工业总公司地质局对分布在全国的放射性废(矿)石堆依轻重缓急安排进行了因地制宜的治理。"十五"期间开展"我国干旱地区放射性废(矿)石治理效果研究",旨在通过较系统的野外调查和室内测试,总结经验,发现问题并提出相应的补救措施。治理工程总体上取得了良好效果。土壤、植物和水样品的研究成果表明,样品中的核素含量基本在当地的环境本底值范围内;γ射线外照射吸收剂量率符合国家相关限值的要求。结合作者多年在该领域的工作经验,对我国放射性废(矿)石的治理方案从治理总体思路、主要技术环节,以及今后需要重点解决的关键技术进行探讨。     

重屏蔽条件下铀材料丰度的时间关联测量分析

针对高原子序数物质屏蔽下的铀材料,提出了一种新的技术方法来估算其铀丰度。首先,用D-T中子发生器的14 MeV中子对铀材料及屏蔽层进行主动质询,同时利用裂变射线探测器得到裂变中子/γ射线时间关联测量谱。然后,利用成像探测器建立的断层扫描图像得到铀材料及屏蔽层的几何和材料参数,并调用不同的铀丰度参数进行蒙特卡罗模拟计算,得到时间关联计算谱。最后,寻找与测量谱最匹配的模拟谱,确定铀材料的实际铀丰度。通过对比裂变射线探测器实验测量得到的所有裂变中子/γ射线时间关联谱,结果发现在各种屏蔽层状态下,高浓铀材料与贫化铀材料的时间关联谱均存在显著差异,可用时间关联谱作为区分不同铀材料丰度的重要技术特征;对于相同铀丰度和屏蔽状态下的铀材料,模拟谱与测量谱吻合较好,表明时间关联谱的模拟与实验分析可为铀材料铀丰度的估算提供技术基础。     

Radiation modification of the uranium complexes in LiF crystals

Time-resolved pulse spectrometry method has been used to research uranium emission in LiF crystals. The spectral-kinetic parameters of uranium photoluminescence for LiF (U) crystals with intentional LiOH doping irradiated in a wide absorbed dose interval 5.10¹-1.10⁶ Gy have been researched for the first time. The effect of the ionizing radiation dose on the relative population and lifetime of the emitting states of the uranium complex has been found for LiF (U) crystals with co-activator alone. The uranium emitting complex in LiF (U) crystal without intentional LiOH co-doping possesses spectral-kinetic characteristics which cannot be affected by the absorbed radiation dose up to 10⁶ Gy.     

自辐射场下UN分子光谱研究

采用优选的B3P86密度泛函方法,对铀原子和氮原子分别使用相对论有效原子实势和6-311+G(d)基组,研究了铀本身产生自辐射场（-0.005～0.005 a.u.）作用下UN基态分子的能隙、谐振频率和费米能级。结果表明：UN分子在自辐射场中的谐振频率与实验值1 007.7 cm^-1基本吻合。能隙和费米能级随自辐射场的增大而增大,占据轨道的电子难以被激发至空轨道而形成激发态,UN分子在自辐射场中更趋于稳定,可阻止N₂等分子扩散到表面内层而腐蚀铀表面,有利于铀在自辐射场中抗腐蚀。