放射性气体活度测量

研制了一套放射性气体活度测量装置及配套测量系统,研究考查了放射性气体活度测量装置及标准测量系统的性能和技术指标;实际测量了放射性气体活度并评定了其不确定度;对放射性气体活度测量系统量值传递技术进行了研究。整套装置技术指标满足有关标准、规范和规程要求,可作为工作标准对我院放射性进行常规测量、检定。     

板型燃料元件燃耗自动测量系统设计

现有的板型燃料元件的燃耗无损测量自动化水平较低,只适用于单点测量。结合板型燃料元件的结构特点及燃耗测量要求,设计板型燃料元件自动测量系统。自动测量系统集成了交互式测点规划、运动系统控制、γ能量谱仪控制、数据处理及结果可视化功能,实现了板型燃料元件多点、分段、自动化、无损燃耗测量。系统运行结果表明:该系统可靠性高,操作简单,能够有效地提高测量效率、精度,降低操作人员的工作量。     

铀材料的中子多重性测量分析方法

多重性测量是一种可以显著提高测量精度、降低测量偏倚的新方法.本文分析了主动法符合测量偏倚较大的原因,介绍了主动法多重性测量的理论关系式,阐述了由测量数据先确定样品增殖,再由经验关系式得到反应系数,进而得到样品质量的数据处理方法.     

大功率RF天线阻抗测量系统的研究

分析了大功率RF天线阻抗的测量原理,提出了传输线探针阵列的测量方法,建立了数学模型,构建了天线阻抗的测量系统,集数据采样、数据处理、参数计算等功能于一体,实现了大功率RF天线阻抗的自动测量,给出了系统的实时测量结果.     

三坐标尺寸测量技术在热室内的应用研究

采用经过系统改进的三坐标尺寸测量设备对燃料元件或组件的尺寸进行了热室内测量研究,在精确定位和分段测量的基础上实现了各项自动测量。测量内容包括板型元件厚度、管型元件直径及椭圆度、组件形位尺寸及起泡高度等。结果表明:三坐标尺寸测量技术能够应用于热室内的各项尺寸测量,并且具有高达2μm的测量精度。     

一体化废树脂/水界面测量系统研发

目前,国内外尚无针对废树脂/水界面测量的仪表。本文提出了一种基于磁致伸缩原理,采用驱动装置作为辅助手段的废树脂/水界面测量方法,进行了测量系统的总体设计,设计了相应的测量系统,并对设计的系统进行了试验验证。测试结果表明,测量系统实现了废树脂/水界面的测量功能,且具有测量精度高、小型化、模块化、提升速度可调、易于安装、检修方便的特点。该系统的成功研制解决了废树脂/水界面测量的难题,在放射性废液处理过程中值得推广和应用。      

热电离质谱直接测定铀氧化物中氧同位素

本文研究了热电离质谱（TIMS)直接测量粉末状铀氧化物中氧同位素的方法,涉及主要测量条件包括环境中氧、样品带材料、样品颗粒大小和测量方式等对测量结果的影响。对仪器的相关测量参数进行了优化,并建立了TIMS直接测量粉末状铀氧化物中¹⁸O、¹⁶O原子个数比的方法。对TIMS法与经典测量氧同位素的氧化法的测量结果进行了比较,两者的相对偏差为0.2%。TIMS法的¹⁸O、¹⁶O原子个数比测量精度优于0.28%。     

HFETR堆辐照孔道释热率测量装置研制

为解决HFETR堆中心孔道活性区相关材料释热率的测量问题,开展了释热率测量装置的研制。在研制过程中,基于量热法的基本原理,辐照孔道的结构限制和反应堆的要求,进行了测量装置结构设计、强度校核和热工分析。测量装置组装完成后,在HFETR堆G07孔道开展了测量试验,同时测得了321不锈钢、6061铝合金和Zr-4合金三种材料在HFETR堆活性区450mm和750mm处的释热率。试验结果显示:测量装置在测量过程中运行稳定可靠,满足HFETR堆安全运行要求;量热计结构小巧紧凑,可同时测量多种材料的释热率;量热计模块化设计,安装于测量装置的不同轴向位置,可同时测量辐照孔道不同轴向位置的释热率;测量结果较好地体现了释热率与堆功率、测量位置的相关性,测量结果可靠有效。     

软件仿真核电站堆芯核测量系统的设计与实现

针对堆芯核测量系统设计制造周期长、关键机械设备采购难、控制系统调试困难等问题,设计了仿真堆芯核测量系统。基于RSView32的仿真测量系统仿真电气设备和机械设备的功能,并配备了测量系统的状态监控界面。本文介绍了仿真测量系统的原理和实现方法。通过仿真测量系统与真实控制软件的联调试验,证实在系统设计过程中,仿真测量系统完全可以代替电气和机械设备,辅助测量系统的控制程序进行调试运行。该仿真测量系统的使用可显著减少机械磨损,缩短控制系统的调试周期。     

方家山核电工程测量质量管理

方家山核电工程测量质量管理包括:工程测量质量体系管理,各等级测量控制网管理,施工测量放样管理,变形监测管理,竣工测量及监督监理管理等。方家山核电工程建设初期,因质量管理缺陷,曾出现工程测量质量问题,面对这些管理问题,方家山项目制定了许多工程测量管理程序、制度和规定,有效地控制了工程测量质量发生。首先,方家山项目部建立了工程测量质量管理小组组织机构,在组织上给予了充分保障;其次,充分运用了PDCA循环管理理念和因果图分析管理方法,在理论分析上为工程测量质量管理提供了有力保障;第三,方家山核电工程测量质量管理结合工程自身特点,严格控制了工程测量质量事前、事中、事后各施工环节,制定了相关工程测量措施和操作规程,搭设了论文交流平台、提供了测量竞赛机会等。通过这些管理措施,方家山核电工程测量质量控制管理水平得到了质的提升,自2009年8月以后,方家山核电工程测量质量事件为0事件,工程测量质量管理得到了有条不紊的开展。方家山项目积极探索出的核电工程测量质量管理模式,不仅有力地控制了方家山项目工程测量质量,而且还为其他核电项目提供了良好的工程测量质量管理借鉴模式。     

Identification of radiation treatment of wheat （Triticum aestivum. L）and rice （Oryza sativa. L） samples using thermoluminescence of contaminating minerals

Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food. Because of the rapid commercialization of irradiated foods throughout the world, compliance of different regulations relating to use of technology in different countries and demand of consumers for clear labelling of irradiated foods, there is need for the development of analytical methods to detect radiation treatment of food. Among several methods studied so far, thermoluminescence （TL） is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles. In this study, the irradiated and unirradiated wheat and rice samples were analyzed using the TL method. The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture （NIFA）, Peshawar. The mineral contaminants were isolated by jet water, ultrasonic treatment, and density gradient. TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50-500℃ using a TL reader. Generally, the glow curves for irradiated samples showed much higher TL intensities （TL1） than the unirradiated samples. The results were normalized by rerradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves （TL2）. The ratio of the area of first glow curve to that of second glow curve （TL1/TL2） was calculated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples. Finally, the shapes of the glow curves for irradiated and unirradiated samples were also analyzed. On the basis of these results （comparison of TL-intensities, TL1/TL2 ratios and shapes of the glow curves）, all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.     

有效探测面积大于1000 cm2的正比计数器测量系统性能测试

为对自制的活性面积高达1 000 cm²的大面积源进行表面发射率定值,同时作为现有2πα、2πβ表面发射率标准装置能力的扩充,研制了一套内置式大面积2π多丝正比计数器测量系统,并利用活性区直径为8 mm的²⁴¹Am点源及活性区面积为10 cm×15 cm的大面积²⁴¹Am和⁹⁰Sr-⁹⁰Y源对其进行计量学性能测试。结果表明：计数器内计数响应均匀性优于±0.4%,有效探测面积达1 400 cm²;所得²⁴¹Am源高压坪曲线的坪长为1 400 V,坪斜为0.27%/100 V,坪区内计数变化为0.87%;⁹⁰Sr-⁹⁰Y源高压坪曲线的坪长为300 V,坪斜为0.75%/100 V,坪区内计数变化为0.80%;10次测量重复性好于0.4%,8 h内短期稳定性好于0.3%,1 a内长期稳定性好于0.8%。     

Preparation of Zn/TiO2 powder and its photocatalytic performance for oxidation of P-nitrophenol

Zn-doped TiO2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis, BET, XRD in this study. Under the irradiation of simulant sunlight, the photocatalytic activity for the degradation of p-nitrophenol was studied too. After irradiation for 2.5 h, the degradation percentage of p-nitrophenol could rise to more than 80 %. The results showed that the spectrum absorption band edge of Zn/TiO2 powder does not broaden obviously comparing with pure TiO2 powder. Zinc exists as Zn （11）. When calcined at 973 K, there is a new phase as ZnTiO3 in Zn/TiO2 catalyst. The order of photocatalytic activity of Zn/TiO2 catalysts calcined at different temperatures for p-nitrophenol is 773 K 〉 673 K 〉 873 K 〉 573 K 〉 973 K and the photocatalytic activity of Zn/TiO2 catalyst calcined at 773 K is better than TiO2 catalysts heated at the same temperature, and outclasses that of commercial TiO2 catalyst. It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irradiation of simulant sunlight.     

Current status of radiation therapy for prostate cancer

Radiotherapy for the treatment of prostate cancer has been extensively explored in the past. Along with the comprehensive understanding of the biology of prostate cancer and rapid advances in terms of technology, the out- come of treatment for the patients with prostate cancer has improved. The authors review radiotherapy as the primary treatment for the disease, with particular emphasis on the technological advances from both the radiobiological and radiophysics aspects. Nonconventional fractionated irradiation like hyper- or hypo-fractionation has been imple- mented in the clinic, the final results still need to be confirmed in the future. Technological advances like IMRT, IGRT, in the last two decades have significantly improved the delivery of external radiotherapy to the prostate. This has re- sulted in an overall increase in the total dose that can be safely delivered to the prostate, which has led to modest im- provements in the biochemical outcome. However, establishing the standard therapy for prostate cancer remains con- troversial. It is hoped that the next decades will bring continued advances in the development of biologicals that will further improve current clinical outcomes.     

The control system for SSRF injection and extraction

This paper introduces the injection and extraction control system design for SSRF,which is a distributed control system aimed at stability and reliability of the pulse power supplies,PPS(Personnel Protection System)and MPS(Machine Protection System).The hardware environment is mainly based on PLC(Programmable Logic Con- troller),and ARM(Advanced RISC Machine)is also applied for studying stability of the power supplies.WinCC and EPICS(Experimental Physics and Industrial Control System)have been selected as the platforms of SCADA(Super- visory Control and Data Acquisition).For unifying the interfacing to the control computer,all front-end equipments are connected via Industrial Ethemet.     

Interaction between uranium and humic acid (Ⅰ): Adsorption behaviors of U(Ⅵ) in soil humic acids

The adsorption behaviors of uranium on three soil humic acids (HAs), which were extracted from soils of different depths at the same site, were investigated under various experimental conditions. The adsorption results showed that U(Ⅵ) in solutions can be adsorbed by the three soil HAs, with the order of FHA (HA from 5 m depth of soil) ＞SHA (HA from the surface) ＞THA (HA from 10 m depth of soil) for adsorption efficiency in each desirable condition, and the adsorption reached equilibrium in about 240 min. Although the maximum adsorption efficiency was adsorption could be described with Langmiur isotherm or Freundlich isotherm equation. The L/S (liquid/solid, mL/g)ratio and pH were important factors influencing the adsorption in our adsorption system besides uranium concentration. The adsorption efficiency decreased with the increase of the L/S ratio and pH at the pH range of 2.0-3.0 for SHA and THA or 2.5 - 6.0 for FHA. However, no significant difference in adsorption of U(Ⅵ) was observed at the experimental temperature. All the results implied that humic substances have different characteristics in samples even collected at the same site.     

水平管内含空气蒸汽强制对流冷凝换热模型研究

为研究含空气蒸汽在水平管内强制对流冷凝换热特性,基于对传热传质过程的分析,建立了管内为环状流与波状流条件下的流动冷凝换热模型。从潜热、显热和液膜3个环节对整个换热过程进行建模,最终得到计算局部冷凝换热系数的理论关系式。模型预测结果与实验数据的对比表明,二者相对偏差在±20%以内,验证了该换热模型的准确性与适用性。通过进一步的研究发现：从换热管入口至出口,随着冷凝的进行,管内换热主要热阻由液膜热阻向气液界面的凝结热阻转变;主流气体对流换热过程基本可忽略。     

Web Services interface of SSRF archive data analysis system

Accelerator database stores various static parameters and real-time data of accelerator. SSRF (Shanghai Synchrotron Radiation Facility) adopts relational database to save the data. We developed a data retrieval system based on XML Web Services for accessing the archive data. It includes a bottom layer interface and an interface applicable for accelerator physics. Client samples exemplifying how to consume the interface are given. The users can browse, retrieve and plot data by the client samples. Also, we give a method to test its stability. The test result and performance are described.     

Investigations on landmine detection by BF3 detector

Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory.     

Information for authors

<正>1.NUCLEAR SCIENCE AND TECHNIQUES(NST),a bimonthly journal,is devoted to all aspects of nuclear science and technology,theoretical or experimental.Its special interest lies in the subjects of synchrotron radiation science and technology;low energy accelerators,radiation technology and applications;radiochemistry,radiopharmaceuticals and nuclear medicine;nuclear electronics and instrumen-