非安全级优选控制技术在CPR1000核电工程中的应用

在CPR1000核电工程项目中存在着诸多参与安全功能的同时受1E和NC级DCS信号控制的非安全级设备,当1E和NC级命令同时到达时,需对1E和NC级DCS命令进行优选处理。本文提出一种优选控制技术,充分考虑不同信号优先级逻辑比较和1E级信号的定期试验回路设计。结果表明,非安全级优选控制技术通过了SL1和SL2抗震试验,为这类非安全级设备的不同级别的控制命令优选处理以及1E级命令的定期试验提供了解决方案。     

浮动核电站仪控系统纵深防御与多样性设计分析

随着核电技术的发展,数字化控制系统在核电站的广泛应用带来的潜在共因故障可能导致系统失效。浮动核电站仪控系统主要由满足独立性要求的安全级和非安全级控制系统组成,通过控制系统防御层、紧急停堆系统防御层、专设安全设施驱动系统防御层以及监测和显示系统防御层的纵深防御设计,形成针对核事故的多层次防御,各个防御层通过实体分隔和电气隔离实现功能独立,并利用多样性设计方法,有效提高系统应对共因故障的能力,从而保证设备和人员的安全。     

基于FPGA的核电DCS功能安全与可靠性评估

探讨了一种基于FPGA技术的核电DCS 2oo4架构系统开展功能安全与可靠性评估方法。运用FMEA技术识别系统级、模块级关键故障模式,针对危险失效模式采取诊断或控制措施,改善和提高核电DCS产品的安全性和可靠性。采用FMEDA技术定量分析模块级产品的平均故障间隔时间及安全失效分数。实验测试结果表明,该方法已在某安全级DCS平台功能安全SIL3认证中得到了充分的应用与验证,同时也为同行业核电DCS系统功能安全认证及可靠性评估提供了参考。     

乏燃料后处理厂通风控制系统设计方案

针对乏燃料后处理厂通风系统的测量和控制需求,设计了一套集中控制的分布式控制系统。在后处理厂通风特点和需求的基础上,分析了其仪控系统的安全分级;阐述了非安全级仪表和安全级仪表的需求,给出选型方案;使用SIEMENS PCS7 DCS系统,基于PROFINET工业以太网技术构建分布式非安全级控制系统;采用满足放化安全级要求的智能二次仪表配合模拟元件的方式集成安全级控制系统,研究并给出了测量、控制和联锁逻辑的构成方式。     

我国首套军民融合核安全级DCS平台——“龙鳞系统”正式发布

正数字化控制系统(DCS)是核电站安全运维的关键,被称为核电站"中枢神经"。12月6日,在中核集团总经理、党组副书记顾军等见证下,我国首套军民融合安全级DCS平台(龙鳞系统)正式发布。该平台由中核集团研发,适用于多种反应堆控制系统,拥有完全自主知识产权,已通过最高等级功能安全认证,部分关键指标达国际领先。从此我国打破了国内核电DCS系统严重依赖进口的被动局面,使我国成为世界上少数掌握该技术的国家。这是中核集团坚持军民融合战略,坚持创新驱动     

集散控制系统在核电站保护系统中的应用

在核电站保护系统中应用基于数字化技术的安全级DCS已替代模拟技术成为主流,因为核电站的安全性要求很高,所以DCS技术的可靠性至关重要。为了确保应用DCS技术设计的可靠性,通过分析相关法规、标准的要求,总结了安全级DCS设计须进行的质量鉴定项及软件验证和确认过程,并结合当前主要应用的几个安全级DCS产品的技术特点,提出了安全级DCS设计开发中应考虑的控制器、智能IO模块、优选驱动模块以及通信等关键技术的要点。     

国产化核电站DAC机柜的设计实现

DAC(Divers Actuation Cabinet)机柜抗震性的实现说明了核电站DCS(DigitalControlSystem数字化控制系统)安全级机柜国产化的可行性。国产化核电站DCS安全级机柜通过抗震试验鉴定,也验证了DAC机柜的抗震性能,确保了核电站DCS安全级机柜国产化的批量生产,是核电站安全级DCS机柜国产化的重要里程碑。     

核电厂无1E级DCS控制设备一回路水压试验的分析

方家山核电工程调试期间遇到了核电厂数字化控制系统(DCS)到货严重拖期的难题,方家山核电工程调试队创新思路,采用核岛控制模块(NC/NC+)加上少量的临时控制变更(TCA)将部分1E级信号引入到NC/NC+机柜,在国内首次成功实施了无1E级DCS控制机柜情况下的一回路水压试验。文章详细阐述了无1E级控制设备实施一回路水压试验的基本原则、可行性分析结论和主要措施等,对同类核电工程的调试工作具有重要借鉴意义。     

核电厂安全级数字化仪控系统通信隔离设计

核电厂仪表和控制系统被称为核电厂的“神经中枢”,对保障核电厂的安全稳定运行安全具有关键作用,是核电厂的重要组成部分。本文依据核电厂相关设计标准要求及参考核电厂的应用需求,提出一种核电厂安全级数字化仪控系统通信隔离设计方法,该方法针对安全级网络通信常见的两种通信方式——点对点通信和多节点通信,在安全级系统内部、安全级系统与非安全级系统之间分别设计独立于处理单元的通信模块,该通信模块本身属于安全级设备,采用异步通信、定制的双端口RAM及确定性的通信协议等方法;在多节点通信中采用双环路拓扑和节点旁路等机制来满足安全级通信隔离设计要求。通过搭建典型工程样机和专家独立工程评审,验证了本方案在工程应用中的正确性和可行性。     

田湾核电站物项的安全分级

核电站物项的安全分级工作中应特别注意全局性、适度性、均衡性这3项原则．物项安全分级的;基本方法,一般是根据物项（部件）的承压外壳损坏对安全的影响,对物项的安全功能进行分级田湾核电站采用的是俄罗斯VVER-1000／428型反应堆装置,其物项安全分级主要采用俄罗斯法规标准：电气和仪控设备采用IEEE-308（80）标准,分为1E级与非1E级;仪控系统及设备的安全分级采用国内标准GB／T15474—1995,分为安全1E级,安全相关SR级和NC非安全级,田湾核电站物项的安全分级必须经中国核安全当局审批并满足中国核安全法规要求．     

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.     

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.     

Gamma radiation levels in the ambient environment of the QNPP Base

Monitoring results of gamma dose rate level in 1992～2004 in the ambient environment of the Qinshan Nuclear Power Plants(QNPP)Base,the northeast of Zhejiang Province,are reported in this paper.It is shown that the gamma dose rate of five monitoring sites of 2.5 km to QNPP Base is 84～113 nGy/h,with an average of 96 nGy/h in the 13 years.The average value is close to the background level of 93 nGy/h prior to operation of the QNPP Base,and is lower than the monitoring result of 101 nGy/h at the reference site in Hangzhou City.Within 50 km from the QNPP Base,the cumulative dose rate of the thermoluminescent dosimeter(TLD)is 90 nGy/h,which is lower than the back- ground level of 111 nGy/h.     

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.