研究性重水反应堆改建的辐射防护评价

本文叙述了研究性重水反应堆改建过程中辐射防护工作的计划和实践。改建期间(1978.12—1980.6)工作人员的集体剂量当量为168人·雷姆。每人每年平均所受外照射剂量当量为0.49雷姆。~(60)Co 是辐射的主要来源。稳定性钴在重水一次回路表面的分布是均匀的。反应堆内壳的放射性强度:~(60)Co 为24居里;~(65)Zn 为6.9居里,研究性重水反应堆改建的目的是:更换已运行二十多年的反应堆内壳,改变堆芯结     

核电站职业性辐射防护的设计要求

本文分析了国外核电站正常运行期间职业性照射的特点及有关的防护标准;提出了与辐射防护基本原则对应的设计指标,建议采用的限值为:个人剂量当量2.5rem/y,人均剂量当量0.5rem/y,集体剂量当量500人·rem/1000MW_e·y;并以图示概述了减少核电站职业性照射的设计措施。     

某研究堆寿期后控制棒取样过程中的辐射防护

分析了某研究堆寿期后控制棒的源项及取样过程中存在的辐射危害,制定了操作过程中的辐射监测和防护方案。监测结果表明,整个取样过程中,操作人员个人累积剂量最大为61 μSv,集体剂量为229 人·μSv,采取的辐射防护措施有效地保证了取样过程中工作人员的辐射安全。     

2004年美国核电厂工作人员的平均集体剂量降至有史以来最低水平

【美国核管会网站2005年6月30日报道】美国核管会(NRC)对美国核电厂工作人员辐照剂量进行的最新调查结果表明,2004年,美国核电厂工作人员的集体剂量平均为100人?雷姆,为有史以来最低水平,是10年前记录的50%。为了计算核电厂工作人员的集体剂量,需要对个人剂量进行加和,并将计算结果用‘人·雷姆’表示。美国人每年因各种放射源照射而受到的剂量平均约为360毫雷姆,核电厂工作人员因职业原因每年额外受到的剂量平均约为160毫雷姆。NRC规定核电厂的工作人员每年所受到的职业辐射剂量最多为5000毫雷姆。NRC核反应堆监管办公室检查计划管理处…     

居民水路旅行集体剂量评价

人类所受辐射照射主要来自天然辐射。环境的人为变化和人类某些活动可能提高或降低天然辐射的照射水平,居民空中旅行中增加了受照剂量而水路旅行减少了受照剂量。我国海岸线长达18000余km,内河航运也十分发达。据交通部1988年统计资料,该年度我国水路旅客周转量近2×10~6万人·km,据农牧渔业部统计资料我国沿海渔业人员近200万,以及在沿海与内河有代表性的六条航线上,航行5625km,共计测量212次,得出每条航线上旅客所受天然辐射剂量率平均值,从而对我国居民水路旅行和从事渔业生产的人员的集体剂量当量做出评价。我国居民1988年度在海上和内河旅行所受天然辐射外照射集体剂量当量为32.7人·Sv,沿海渔业人员在海上作业期间所受天然辐射外照射集体剂量当量为265.3人·Sv。     

我国第一座研究性重水反应堆运行廿年的辐射防护评价

本文叙述了研究性重水反应堆运行20年来的辐射防护工作。工作人员所受集体剂量当量共计1537.59man·rem;平均每人每年受剂量当量0.62rem;反应堆运行1MWY 平均付出的集体剂量当量为34.63man·rem。释放到环境中的放射性物质低于容许限量。对工作人员全面医学检查结果,未见可资诊断的辐射损伤者。一回路磨损腐蚀产物活化生成的~(60)Co 是造成内外照射的主要核素之一。     

中国核工业30年辐射环境质量评价

中国核工业自1955建立以来,已形成一个完整的工业系统。核工业辐射环境质量评价于1981年着手工作,调查了各核设施80km范围内的人口分布、农作物分布、食物组成以及气象、水文、地质等资料,统计并分析了流出物和环境监测资料。辐射环境质量评价的计算采用Y3001计算机程序。计算结果表明,所有核设施周围的关键居民组所受的有效剂量当量小于国家规定的年剂量限值。80%的关键居民组所受的剂量小于天然辐射剂量(3mSv·a~(-1))的10%。整个核工业(核设施周围涉及1.5亿人)总的年平均集体剂量当量为23人·Sv,低于天然辐射剂量的10×10~(-2)%,远低于非核工业或人为活动的危害值。根据我国核工业发展计划,预测到2000年时整个核工业产生的年集体剂量当量为59人·Sv。     

中国核工业30年辐射环境质量评价

中国核工业自1955年建立以来,已形成一个完整的工业系统。核工业辐射环境质量评价于1981年着手工作,调查了各核设施80km范围内的人口分布、农作物分布、食物组成以及气象、水文、地质等资料,统计并分析了流出物和环境监测资料。辐射环境质量评价的计算采用Y3001计算机程序。计算结果表明,所有核设施周围的关键居民组所受的有效剂量当量小于国家规定的年剂量限值。80％的关键居民组所受的剂量小于天然辐射剂量(3 mSv·a~(-1)的10％。整个核工业(核设施周围涉及1.5亿人)总的年平均集体剂量当量为23人·Sv,低于天然辐射剂量的1×10~(-2)％,远低于非核工业或人为活动的危害值。根据我国核工业发展计划,预测到2000年时整个核工业产生的年集体剂量当量为59人·Sv。     

中国核工业30年辐射环境质量评价(英文)

中国核工业自1955年建立以来,已形成一个完整的工业系统。核工业辐射环境质量评价于1981年着手工作,调查了各核设施80km范围内的人口分布、农作物分布、食物组成以及气象、水文、地质等资料,统计并分析了流出物和环境监测资料。辐射环境质量评价的计算采用Y3001计算机程序。计算结果表明,所有核设施周围的关键居民组所受的有效剂量当量小于国家规定的年剂量限值。80％的关键居民组所受的剂量小于天然辐射剂量的10％。整个核工业总的年平均集体剂量当量为23人·Sv,低于天然辐射剂量的0.01％,远低于非核工业或人为活动的危害值。根据我国核工业发展计划,预测到2000年时整个核工业产生的年集体剂量当量为59人·Sv。     

~(241)Am-Be源和~(226)Ra-Be源的中子注量-剂量换算系数

在中子剂量仪表刻度和中子剂量计算中经常遇到单位注量中子与比释动能、吸收剂量、剂量当量之间的换算关系。它们之间的数值关系通常称为中子注量-剂量换算系数。在《放射防护规定》中规定职业放射性工作人员最大容许剂量当量为每年5雷姆。同时又对2.5毫雷姆/小时对应的中子通量(中子/厘米~2·秒)进行了规定(见附表1第7栏)。国际辐射防     

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.     

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.     

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.     

PLASMA SCIENCE AND TECHNOLOGY AUTHOR INDEX TO VOLUME 16(2014)

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Radioactivity levels in soil of salt field area,Kelambakkam,Tamilnadu,India

Soil samples in and around salt field area have been analyzed for natural radioactivity concentration using gamma ray spectrometer.The activity concentration for ~(232)Th,~(238)U and ~(40)K are ranged from 27.88 to 45.27 Bq/kg, from BDL to 13.30 Bq/kg,and from 135.54 to 381.28 Bq/kg,respectively.The measured activity concentrations for these radionuclides were compared with world average activity of soil.The average activity concentration of ~(232)Th in the present study is 1.19 times higher than world median value while the activity of ~(238)U and ~(40)K is found to be lower. The absorbed dose rates due to these radionuclides were calculated.The average absorbed gamma dose rate due to the presence of ~(232)Th,~(238)U and ~(40)K in soil samples is 36.99 nGy·h~(-1).These results indicate no radiological anomaly. The data presented in this study will serve as a base line survey for primordial radionuclides concentration in the study area.