核恐怖事件的防范与应急措施

"9·11"事件后,人们普遍担心恐怖分子会将包括核电站在内的核设施作为袭击目标,轰炸这些核设施,使其释放出放射性物质,危害公众的生命和财产安全;或者散布放射性物质,造成"核恐慌",从而达到扰乱社会秩序、打击经济的恐怖目的.为了防范和杜绝核恐怖事件的发生,各国均采取了积极的安全保卫措施,并在积极审核和制定核恐怖事件发生后的应急措施.国际社会也在加强合作,将发生核恐怖事件的可能性降至最低.本文详细介绍了恐怖分子利用散布放射性物质制造核恐怖事件的可能方式和后果,分析了核恐怖事件所造成的影响,提出了处理这些核恐怖事件应采取的应急措施.     

浅谈武警防化兵分队对核与辐射恐怖事件的处置

核与辐射恐怖比常规恐怖活动性质更特殊、防范更棘手,防范和处置核与辐射恐怖事件已经成为反恐面临的一个重点课题。本文根据核与辐射恐怖事件的特点,结合武警防化兵分队的任务,探讨了武警防化兵分队参与处置此类事件的基本方法与措施。     

核与辐射恐怖事件及其应对策略

使用大规模杀伤性武器的“超级恐怖主义”,已成为当代国际社会面临的现实威胁。核与辐射恐怖事件引起放射性物质的释放,将导致人员伤亡和心理恐慌,从而破坏国家公务、民众生活、社会安定与经济发展．它给人类社会造成危害和影响极大,引起世人关注。分析了核与辐射恐怖事件的可能发生方式与危害,以核与辐射恐怖事件的三大类别与典型情景为背景,提出了核与辐射恐怖事件的应对策略。     

核舰船核事故舱室辐射后果评价研究

本文结合核舰船的设计特点和实际运行经验，分析了核事故时放射性核素由核反应堆舱（以下简称堆舱）向其他舱室的传输途径及在各舱室中的分布，给出了放射性素活度和人员剂量的估算方法，计算了核事故情况下各舱室的辐射水平和人员的受照剂量，后果评价表明，设计基准事故时，各舱室辐射后果较轻，人员剂量没有超过有关标准规定的剂量限值，严重事故时，堆舱邻舱辐射后果严重，人员剂量超过有关标准规定的剂量限值。     

口岸核与辐射恐怖事件现场应急处置措施

口岸作为国家安全和社会稳定的第一防线,目前还缺乏应对恐怖袭击--特别是核与辐射恐怖袭击的经验.口岸核与辐射应急工作是一项系统工程,需要有关部门的通力协作,把口岸执法与反恐工作有机结合.为了做好应急响应,口岸检验检疫部门要明确现场处置各专业组的职责分工、任务要求以及加强应急程序与相应措施的准备.本文根据核与辐射恐怖事件的特点,结合2007年4月27日国家质检总局首次核与辐射恐怖事件应急处置演练的实战过程,对口岸核与辐射快速应对和处置的关键技术、现场应急措施进行总结和探索.     

核恐怖事件相对风险评估的简易概率方法

本文基于事件树和概率分析方法,提出了一种简单的核恐怖事件风险分析的概率评估方法,分析了4类核恐怖事件的单次事件的危害;由于核恐怖事件至今尚未发生,相关数据库对潜在的核恐怖事件的统计数据很少,在相关的潜在事例和假设的基础上,演示性地分析了4种方式引起核恐怖事件的相对概率和相对风险.综合示例的分析结果表明,发生4种核恐怖事件单次事件的危害由大到小依次为:使用核爆炸装置和使用简易核爆炸装置、攻击核设施、使用"脏弹".而对假设前提下的计算示例,成功发生的概率由大到小依次为:使用放射性"脏弹"、攻击核设施、使用简易核爆炸装置和使用核爆炸装置;4种方式引发的核恐怖事件风险由大到小分依次为:使用放射性"脏弹"、使用简易核爆炸装置、攻击核设施、使用核爆炸装置.     

含钚材料恐怖事件的后果分析

基于数值仿真计算手段,定量分析了含钚材料恐怖事件中炸药爆炸条件下钚材料气溶胶的转化份额;针对不同可吸入气溶胶比例,应用HotSpot核事故后果评价模型计算了有关辐射特征量。结果表明,不同可吸入气溶胶比例对于辐射危害防护及处置有着明显的影响。     

切尔诺贝利核事故及其后果

根据各国已经发表的资料 ,特别是最近在国际辐射防护学会 ( IRPA)第 1 0届大会上发表的最新资料 ,综述了切尔诺贝利核事故的基本情况 ,特别是它所造成的辐射后果及其伤亡情况。希望借此对这一核工业有史以来最严重的核事故做出客观的估价 ,吸取经验教训 ,促进我国核工业的健康发展。     

针对核恐怖活动的核监测需求分析

分析了核和辐射恐怖威胁的态势，给出了防范与响应核和辐射恐怖活动的核监测需求初步分析。     

岩庄陨石的热释光位移和热事件年代研究

通过对岩庄陨石自然热释光的测定、退火及β辐照诱发热释光(以下简称TL)实验,发现此陨石的热释光存在着两种特殊现象:(1)陨石样品在500℃温度下退火后,经β射线辐照诱发TL,其峰温随辐照剂量的增大而向低温方向移动,并存在着一定的移动规律;(2)陨石样品经均匀地升温退火,退火温度达600℃以上其诱发TL峰温比未经退火的峰温要高。岩庄陨石样品由黑色与浅色两部分组成,两部分样品的等效β剂量测定结果分别为9238Gy和25753Gy,按年剂量率0.1Gy/a计算,结果说明这两部分组成的热事件年代不一样,受热历史也不相同。     

铀纯化转化设施始发事件分析

始发事件分析是概率安全分析的基础,对始发事件进行定量化评价是概率安全分析获得量化风险结果的必要条件。本文采用工程评估和演绎分析相结合的方法识别了典型铀纯化转化设施的始发事件,根据设施安全保护措施的异同将始发事件分为5组,并对铀纯化转化设施主要关注的UF₆泄漏事件采用事件树分析法进行事故序列分析,得到UF₆泄漏事件序列和相应的频率。     

Identification of initiating events for pressurized water reactor accidents

In order to aid operators in identifying the different initiating events as defined in the Final Safety Analysis Report (FSAR), we develop a novel identification procedure. The procedure is based on the monitoring of three key system parameters in a pressurized water reactor (PWR), i.e., the pressure, the average temperature, and the temperature difference of the hot-leg and cold-leg of the reactor coolant system. By monitoring the system thermal state diagram in a pressure–temperature space, an operator can easily identify what initiating event is taking place while a static point in the diagram starts to move. The event data pool is first established by storing the transient analysis results for events of different types using the optimal estimated RELAP5 model. Since the variation ranges of system key parameters at a specific time represent the specific character for each initiating event, the identification procedure can easily determine which cases in which the event data pool can be fitted to on-line data using only variation range comparison without complex calculations. This identification method is believed to be able to help the plant operator to identify the different events and then execute the Emergency Operating Procedure more effectively.     

基于离散Gabor分布的地震事件识别

描述了一种联合时频分析方法－Ｇａｂｏｒ分布,并且讨论了信号离散Ｇａｂｏｒ分布的计算机实现方法。根据公认有效的地震事件识别判 据一体液震级ｍｂ与面波震级Ｍｓ之比ｍｂ／Ｍｓ,结合信号的Ｇａｂｏｒ分布谱图,在联合时频域对这一识别判据进行了新的描述,并取得了较好的识别结果。     

大亚湾核电站执照运行事件原因趋势分析

对大亚湾核电站1993/2003年所有人因相关执照运行事件进行了原因分类、趋势分析,并重点分析了电站人员在遵守和执行规定与规程方面的不足,为核电站改善人的行为提供方向性参考。     

Transient behaviors of heavy water reflector system during postulated initiating events (PIEs)

This study investigates the transient thermal-hydraulic behaviors of a heavy water reflector system during various postulated initiating events (PIEs). The following events are considered in the analysis: (1) loss of heavy water system (HWS) flow, (2) heavy water leakage, (3) loss of secondary cooling flow, and (4) dilution of heavy water. The sequence of each event is described, and thermal-hydraulic parameters such as the heavy water temperature, system pressure, flow rate, and heavy water level are monitored. To regulate the HWS, the heavy water temperature at the outlet of the heavy water vessel, the heavy water level in the expansion tank, and the flow rate in the HWS are used as the reactor regulating system (RRS) setbacks. In the event of loss of HWS flow, the standby pump kicks off to recover it, and none of the RRS setback signals are triggered. In the event of heavy water leakage, a low-level RRS setback signal trips the reactor, and the temperature rise in the HWS is not significant. The total amount of heavy water leakage with a break at the outlet of the heat exchanger is approximately 550 L. In the event of loss of secondary cooling flow, a high-temperature RRS setback signal trips the reactor. In the event of heavy water dilution, a low-level RRS setback signal trips the reactor. In the case of a pipe rupture at the highest point in the HWS inside the pool, the RRS setback signal is triggered at 83.9 s from the initiation. At the instant of the reactor trip, the reactor power increases to 150% of full power because of the degraded purity of the heavy water––95.7%. For the event of heavy water dilution, a reactor protection system (RPS) setback such as the reactor power difference between a neutron detector and a gamma detector should be used to trip the reactor.     

反对恐怖主义对策--辐射防护的新领域

反对恐怖主义已成为辐射防护工作者面临的一项新任务。本文介绍了不同类型核与辐射恐怖袭击的特征及其威胁水平、各类事件的潜在后果和发生概率，以及从两个层次上对此类威胁的响应。在危机管理层次，介绍了各种预防措施、国际原于能机构已做的一些工作和美国国内动向；在后果管理层次，列出了美国辐射防护与测量委员会提出的主要内容。对国内的一些进展也作了介绍。     

N-acetylcysteine protect lymphocytes and cytokines against heavy ion irradiation via counteracting the glutamate

We evaluated the protective effect of N-acetylcysteine (NAC) on immunity system irradiated by 12C6+ ion beam. Kun-Ming mice were whole-body irradiated by 12C6+ ion at doses of 0, 0.5, 1, 1.5, 2, 2.5 and 3 Gy. The results showed that in saline group, the lymphocytes DNA double-strand breaks (DSBs), maleic dialdehyde, thymocytes number in G 0 /G 1 and apoptosis percentage increased with dose increment, and the levels of interferon-γ, glutathione, superoxide radical (SOD) and natural killer cells activity decreased with dose increment. However, there were no significant changes in NAC-treated group. The data indicated that pre-treatment with NAC could significantly remove the ROS by counteracting the glutamate, decrease excessive lipid peroxidation reaction and SOD damages, and protect DNA, lymphocytes and cytokines against irradiation.     

基于部队核事故后果分析的系统开发

通过分析国内核设施事故后果评价技术现状及相关系统的功能特征,研究部队核事故后果评价技术的发展情况,比较两者在评价技术方法和功能模式上的异同点。在此基础上,针对前期研制的一种适用于部队核事故后果评价的软件系统,在功能组成、开发应用和优化升级等方面进行了探讨,为部队核武器事故后果评价技术发展提供了启示。     

Analysis of human-induced initiating events in a multi-unit loss of offsite power scenario

ABSTRACT

Human-induced initiators (category-B actions) are the initiators that are caused by human errors and are rarely explicitly identified and modeled in probabilistic safety assessments (PSAs). The current concern over the safety of multi-unit nuclear power sites is also a motivation for this research. This study proposes a novel process for identifying and quantifying category-B actions and ultimately, how to derive a human-induced initiating event frequency in a multi-unit scenario. Hence, this study fundamentally applies a scenario–system–action search scheme using maintenance and testing procedures, quantifies the human error probability by using the cause-based decision tree and technique for human error rate prediction method, models category-B human actions in the developed fault trees, and derives the human-induced initiating event frequency. The procedure, which is used in this approach, essentially involves system analysis, fault tree development, human error identification, screening, and quantification. The multi-unit loss of offsite power is used as an example accident situation which illustrates the application of the suggested method. Hence, the human-induced initiating event frequency for the loss of off-site power scenario for two units is derived. The application of this method would advance the efforts concerning multi-unit nuclear power plant (NPP) site risk analysis.