关于确定秦山核电厂（一期工程）烟羽应急计划区大小的建议

本文按照国际上划分应急计划区的一般原则,参考美国建立烟羽应急计划区的具体准则和方法,结合我国国情和秦山核电厂厂址的环境特征与事故释放特征,在对假想事故释放的预期剂量和相应的干预水平进行比较后,建议将秦山核电厂(一期工程)的烟羽应急计划区分为内区和外区。内区半径为3—5km,制定有撤离计划;外区半径为7—10km,一般不考虑采取撤离措施。     

AP1000核电厂烟羽应急计划区划分初步研究

应急计划区的划分是核电厂应急计划制定中的重要内容之一。第三代核电机组AP1000应急计划区的划分研究,对其应急计划和应急准备工作具有十分重要的意义。首先介绍了应急计划区划分的一般方法以及我国相关法规的要求;然后以某滨海厂址为例,根据现阶段AP1000事故源项的研究结果和该厂址的气象观测数据,使用PAVAN和MACCS程序对相应的事故后果进行计算;最后结合相应的准则对计算结果进行分析和评价。初步的研究结果表明,AP1000核电厂取半径3km范围作为烟羽应急计划区的内区、半径7km范围作为烟羽应急计划区的外区是合适的。     

台山核电厂EPR核电机组烟羽应急计划区评估

采用事故后果分析程序(MACCS2)对台山核电厂欧洲压水堆(EPR)机组应急计划区范围进行评估。气象数据采用厂址气象塔2007年9月至2008年8月逐时气象数据,源项和释放特征等数据采用二级概率安全分析(PSA)研究成果。对台山核电厂应急计划进行评估的结果表明,台山核电厂应急计划区半径应小于0.5 km,这与EPR的设计目标是一致。但根据国家法律法规要求,结合厂址特征,推荐台山核电厂应急计划区内区半径为4 km,外区半径为7 km。     

确定核动力厂应急计划区大小的准则和方法

在详细介绍了一些国家或地区确定核电厂应急计划区的准则和方法的基础上,将确定应急计划区的方法主要分为确定论和概率论两种,并进行了评论和比较。分析了应用美国确定应急计划区大小的准则时可能遇到的困难,提出了我国确定核电厂应急计划区大小准则的建议。最后用广东大亚湾核电站概率安全评价第三级事故后果的计算说明,应用本文所建议的准则,大亚湾核电站不论是否安装砂堆过滤器,采用10km作为烟羽应急计划区半径均是适宜的。     

核电厂烟羽应急计划区划分探讨

应急计划区划分是核电厂应急准备工作的一项重要内容。基于国家推荐的划分原则,分析某AP1000核电机组烟羽应急计划区计算方法及计算结果,并从电厂安全、事故后果、人口因素等方面讨论实际划分中遇到的问题,提出对后续机组烟羽应急计划区划分的建议。     

陆上小型堆烟羽应急计划区划分初步研究

小型堆烟羽应急计划区(EPZ)大小作为其市场推广和应用的重要外部约束条件之一,意味着制定合适的划分准则和确立其大小范围具有十分重大的意义。结合现行大堆烟羽应急计划区(EPZ)的划分准则,本文分析了国内外小型堆烟羽应急计划区(EPZ)划分方法,提出陆上小型堆采用剂量/距离的划分方法。在研究中,基于MAAP程序对某小型堆进行建模计算,从中得出了较为合理的机理性应急源项;并通过大气扩散计算软件MACCS程序进行烟羽应急计划区(EPZ)计算;同时对厂址差异进行相关的灵敏性分析。     

核电站严重事故后果概率安全评价方法研究

核电站严重事故后果概率安全评价(PSA)是采用概率论的方法对核电站放射性后果进行分析,并定量给出放射性物质对核电站周围公众的健康效应影响。以国内某压水堆核电站为参考厂址,建立合适的场外后果分析模型。采用分层抽样方法对参考厂址1a的气象数据进行抽样,源项和释放特征等数据取自二级PSA的研究结果。利用事故后果评价程序对核电站严重事故后果进行计算,并用概率论方法对结果进行评估。通过计算将各事故和事故谱的场外个人剂量表示为CCDF曲线和总频率-剂量曲线,再用概率论方法得到不同距离处个人剂量超过指定剂量的条件概率;也可用此方法对确定烟羽应急计划区的安全准则中所描述的"大多数严重事故序列"进行量化。     

小型堆应急计划区划分研究

利用一体化严重事故分析程序(MELCOR)对小型堆断电事故进行仿真分析,并将结果作为大气扩散计算软件MACCS的输入,计算分析某滨海地区放射性后果。结合建立的小型堆应急计划区划分准则,通过计算确定适用于小型堆的应急计划区大小。     

核电厂烟羽应急计划区划分方法研究

结合不同类型反应堆的安全特性,对不同的烟羽应急计划区(PEPZ)划分方法进行对比分析,然后依据反应堆类型进行系统归类,提出不同堆型所适用的烟羽应急计划区划分方法,最后以我国的模块式高温气冷堆示范电厂(HTR-PM)为例进行划分方法的初步应用。初步研究结果表明,HTR-PM在厂址边界处满足烟羽应急计划区的划分准则,相对于目前的大型轻水堆,可以明显减小其烟羽应急计划区。     

小型核反应堆应急计划区的研究

适用于大型核反应堆的应急计划区划分方法不能完全适用于小型核反应堆。应急计划区的划分需充分考虑公众可能受到的预期剂量和可防止剂量,将所得到的剂量数据与规定的干预水平相比较,确定应急计划区范围。以烟羽应急计划区范围外的预期剂量不超过10 m Sv为例,利用MACCS软件计算在指定应急计划区范围的限制条件下,对释放源项水平的要求,详细说明应急计划区的划分及计算过程。     

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。     

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.     

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.     

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%。     

Assessment of radioactivity levels in some oil samples from the western desert, Egypt

Distributions of natural gamma-emitting radionuclides were determined in 93 oil samples collected from some petroleum fields in the western desert of Egypt. The radioisotope activities in the area under investigation lay in the range of (21 ± 4) to (38 ± 13) Bq?L-1 for 226Ra, (9 ± 2) to (15 ± 5) Bq?L-1 for 232Th, and (154 ± 28) to (303 ± 54) Bq?L-1 for 40K. The mean values were 27, 12, and 201 Bq?L-1, respectively. Among oils, variations in radionuclide ac- tivities could be on account of differences in TDS, HCO3, and Ba, with high or low pH. In this environment, oil prop- erties differently affected the mobilization of natural radionuclides. The range of 226Ra variation had been compared with available data from other countries. The calculated absorbed dose rate ranged from 22.33 to 32.66 nGy?h-1 in lo- cation (B) and (E) respectively, which was less than the accepted value.     

Preparation and properties of 117m Sn(IV)-TTHMP in in-vitro and in small animals

In this work,TTHMP was synthesized and labelled with 117m Sn.The preparation conditions,stability and lipophilicity of 117m Sn(IV)-TTHMP were investigated.Biodistribution of the complex in rabbits and mice was studied.It was found that the quantity of TTHMP and pH value of the prepararion solution had vital effects on the labeling yield of 117m Sn(IV)-TTHMP.It was also found that 117m Sn(IV)-TTHMP was hydrophilic and stable at room temperature and 37℃ in open air 117m Sn(IV)-TTHMP showed unexpectedly high bone uptake and bone-to-blood ratio in the animals.This made it potentially useful as an reagent for skeletal scintigraphy and radiotherapy of bone tumors.     

The role of AGFA high-energy CR in the calibration and quality control of multileaf collimators （MLC）

Linear accelerators equipped with multileaf collimators （MLC） are becoming more common and are widely used in the intensity-modulated radiotherapy （IMRT）. There is an imperative need to ensure the commissioning specification of the linear accelerators for the sake of quality assurance （QA） and quality control （QC）. This paper is aimed to investigate the role of AGFA high-energy CR （Computed Radiography） in calibrating dynamic multileaf collimators and evaluating the accuracy of the leaf position. The result shows that AGFA high-energy CR can easily and conveniently be used to calibrate MLC and verify its position. Hence, the application of AGFA high-energy CR is proved to be an accurate and time-saving method for routine MLC QC, especially when MLC calibration adjustments are required.