“华龙一号”堆芯冷却监测系统设计

“华龙一号”是我国自主研发的第三代核电站，其反应堆及一回路系统在设计中对固有安全性提出了更高的要求。对于二代加核电厂堆芯冷却监测系统（CCMS），需要在反应堆底部开孔测量水位。该设计降低了反应堆固有安全性，必须重新设计。本文设计了一种新型CCMS，其探测器从压力容器顶盖插入堆芯进行直接测量，不但提高了关键点的水位测量准确度，同时避免了压力容器底部开孔，满足了“华龙一号”反应堆固有安全性要求。      

核电厂DCS配电系统的设计与应用

核电厂DCS系统是核电厂重要的系统,其可靠性对核电厂机组的安全性和经济性非常关键,DCS系统的配电系统作为DCS系统的能源供应系统,其重要性不言自明。文章以中国压水堆二代改进型机组DCS配电系统为实例,对核电厂DCS配电系统进行研究,通过实验的方法和仿真分析的方法来验证设计方案,从而使DCS配电系统满足DCS系统的设计原则、设计要求。文章详细描述了核电厂DCS配电系统从设计原则出发,详细分析需求,结合工程实际进行设计、验证、应用等过程。     

快中子反应堆非能动停堆系统中控制棒驱动杆磁性连接件的设计与有限元分析

为确保快中子反应堆的安全运行,提出了一种非能动性的智能触发停堆系统,完成了对该系统中的永久磁铁的设计,采用ANSYS软件对永久磁铁进行热分析并进行安全评估,验证了该系统的安全性和有效性.     

ADS加速器失束次临界反应堆动态特性研究

加速器驱动系统(ADS)中次临界堆芯的功率水平依靠强流质子轰击散裂靶产生的中子源来维持.加速器较为频繁的失柬问题,必将对ADS次临界反应堆安全性产生影响.研究了ADS系统失束事故特性,设计开发出具有较强针对性的用于ADS失束事故分析软件,对加速器驱动快中子次临界反应堆的动态响应开展了初步研究.结论表明仅靠断束停堆,仍有可能危及次临界反应堆的安全性.建议增设辅助停堆保护系统以提高ADS安全性.     

反渗透法处理放射性废水的安全性分析

反渗透放射性废水处理系统的预处理系统工作方式为"叠片式过滤+超滤",其安全性分析和评估内容包括:工艺设备的可靠性、运行维护的安全性和退役安全性,以及反渗透膜组件的辐射安全估算。分析表明:通过合理的工艺设计可以保证反渗透系统的安全可靠,反渗透膜表面的剂量当量率小于0.04 mSv/h,能够保证操作人员的安全。     

冷中子源中氢系统的纵深防御设计

反应堆冷中子源装置的安全性包括核安全、辐射安全和氢安全,其中氢安全是最复杂的一方面.冷中子源氢系统一般采取纵深防御的安全设计方法,即通过多重屏障的技术措施尽可能杜绝氢和空气(氧气)直接接触的可能性.本文详细描述了一座建设中的反应堆冷中子源氢系统的纵深防御安全设计特点,这种安全设计可以确保冷中子源的氢安全性.     

核电厂安全系统的系列配置对可靠性与机组安全的影响方案研究

本文介绍了核电厂安全系统设计的要求、具体实践及其技术发展趋势,论述了在核电厂安全设计中安全系统的系列配置与安全系统可靠性及核电厂安全水平的关系。本文还特别讨论了三环路压水堆核电厂安全系统的配置所采用的3个独立系列设计理念的安全性以及与其他配置的比较。结果表明,3个独立系列的安全系列设计能提高核电厂的安全性,满足核电厂的经济性,使配置更加合理。     

提高加速器运动控制精度和安全性的方法

静电偏转板是加速器束流注入和引出系统中的重要装置,其运动控制系统在定位精度、安全性、稳定可靠和方便性方面有较高的要求。本文以实际工程为例,介绍了几种基于PLC功能模块实现的运动控制中提高定位精度、设备安全性、使用方便性的方法和设计考虑。这些方法和设计在实际工程应用中得到了检验,可为同类运动控制系统的建设提供借鉴和参考。     

板式换热器在CARR中的应用

着重介绍了CARR工程中重水换热器、主换热器的选型及设计过程。通过安全性和经济性等方面的对比,可以看出板式换热器比套管式换热器更具有优越性。板式换热器在系统中的应用对今后的设计具有一定的参考价值。     

加速器屏蔽室入口安全系统的设计

为进一步确保辐照过程中人员的人身安全,对辐照加速器小车系统迷宫入口设计一种光电联锁系统。该光电联锁系统根据小车具体结构采用28组光电开关多点分布组合设计,设置于辐照加速器屏蔽室入口处,具有检测到非特定特征小车或物体进入屏蔽室时发出报警信号的功能。为辐射、化学危害,核能利用等提供有力的安全保障和技术支持,对设备的操作便捷性、场地安全性有重要指导意义。     

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。     

The preclinical pharmacological study of dopamine transporter imaging agent 18F-FP-β-CIT

The paper is to study pharmacologic characteristics of 18F-FP-β-CIT (18F-N-(3-fluoropropyl)-2β- carbomethoxy-3β- (4-iodophenyl)nortropane) as an imaging agent for dopamine transporter. The radiochemical purity of 18F-FP-β-CIT in aqueous solution was over 95% after standing at room temperature for 4h. Biodistribution displayed rapid uptake in rat brain (1.375 %ID/organ at 5min and 0.100 %ID/organ at 180 min) and the striatal uptake was 1.444,0.731, 0.397, 0.230 and 0.146 %ID/g at 5, 30, 60, 120 and 180 min, respectively. The values of striatum/cerebellum,striatum/frontal cortex and striatum / hippocampus in rat's brain at 30 min were 3.38, 2.17 and 2.40 respectively. The uptake in striatum can be blocked by β-CFT, suggesting that 18F-FP-β-CIT binds to DAT peculiarly. The compound was rapidly cleared from monkey's blood. The striatal uptake was bilaterally decreased in the left-sided lesioned PD rats, compared with normal control. Brain PET imaging studies in normal monkey showed that 18F-FP-β-CIT was concentrated in striatum. The test of undue toxicity showed that the dose received by mice was 1250 times as by human, which indicates that 18F-FP-β-CIT is very safe. So 18F-FP-β-CIT is a promising PET imaging agent for DAT with safety and validity.     

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.