核事故应急大气扩散模型ARTM验证与评价

  目的  针对国内外普遍关注的核事故应急决策支持与事故后果评价的问题,围绕目前验证、评价大气扩散模型的两个主要困难。  方法  应用目前国际上应用广泛的KINCAID示踪实验数据集和MVK模型验证评价方法,验证了评价放射性核素大气扩散模型ARTM（Atmospheric Radionuclide Transport Model）。  结果  统计结果表明:ARTM的模拟结果基本上是可信赖的,3 km内的预测有低估的趋势,5 km外的预测有高估的趋势。  结论  ARTM模型总体上可以应用于核电厂事故后果评价。     

基于GIS的大气污染物扩散模拟分析系统设计与实现

将GIS技术与环境模型紧密集成,以.Net平台为基础,利用ArcGIS Engine 9.3组件开发了基于GIS的大气污染物扩散模拟分析系统,针对点状污染源的大气污染物扩散情况,利用DEM数据进行地形修正及模拟结果成图输出,并以重庆市中国六冶钢结构厂为例对其排放的污染气体进行了扩散模拟.系统运行结果表明,该系统可较准确地模拟污染气体的扩散情况,且简单、快速.     

ADMS模式在大气扩散模拟中的应用研究

采用ADMS模式,以位于青岛市南翼的一处矿石码头大气扩散模拟为例进行实例研究,通过合理选取预测网格点和相应地形和气象等参数,模拟各种大气预测情景模式下污染物的分布情况,从科学性、工程性、可操作性等多方面考虑,提出了模型参数选取的技巧和方法.为大气环境影响评价的研究和实践工作提供参考和借鉴,为今后开展大气影响预测评价工作提供思路和指导.     

湿法脱硫尾气排放的烟羽扩散数值模拟

为了研究湿法脱硫尾气排放的烟羽扩散特性,基于大气环境基本理论,以在大气中扩散的混合气流为研究对象,通过FLUENT软件对不同参数下的烟羽扩散进行三维计算,模拟湿法脱硫尾气在大气中的温度场、速度场,进而获得湿法脱硫尾气的轨迹发展和扩散过程,并通过模拟数据与实测数据对比,验证了结果的可信性。结果表明:环境温度与烟气温度的降低,可有效缩减烟羽长度;烟气流速的提高对烟羽气相扩散有促进作用,烟羽抬升高度、落地距离和扩散宽度都有明显增加;环境风速和烟气速度的增加对液滴颗粒扩散影响显著,有利于湿烟羽的扩散。     

受限空间内氢气泄漏扩散行为的数值模拟

氢分子是自然界中最小的分子,很容易通过管道接头、阀门等位置发生泄漏。由于氢气的易燃易爆属性,泄漏后形成的可燃气云一旦遇到火源容易演变成事故。因此,对氢气泄漏扩散行为进行研究有助于掌握氢气事故演化发展规律,对于事故预防具有重要意义。针对一个尺寸为0.47 m×0.33 m×0.20 m的立方体空间建立几何模型,采用自主研发的MPPBuoyantEpplFoam求解器对该模型内的氢气泄漏扩散行为进行了数值模拟,获得了氢气泄漏后的氢气浓度分布、扩散速度分布及流动扩散规律,通过与相关文献中的实验结果进行对比,二者吻合较好,初步验证了该求解器多组分扩散功能的准确性。研究结果表明,在受限空间内,氢气泄漏后表现出如下流动扩散规律：1)氢气从模型顶部竖直向下喷入计算域后,在周围静止空气阻滞作用和浮升力作用下,扩散速度迅速减小,流动的动量控制区变短;2)在氢气注入阶段,计算域氢气浓度分布会在浮力作用下呈现明显的分层效应,上部的氢气浓度高,下部的氢气浓度低;3)氢气停止注入后,在分子扩散作用下,计算域上下部氢气浓度差逐渐变小,并最终达到均匀混合。     

高含硫天然气管道泄漏扩散数值模拟

天然气在集输过程中,由于管道老化、腐蚀等因素引起的泄漏事故时有发生,其中以小孔径泄漏事故发生概率偏大.本文利用软件对高含硫天然气小孔径泄漏进行数值模拟,模拟结果显示,泄漏气体中甲烷和硫化氢的扩散范围、浓度含量、烟云高度受风速影响明显.高含硫天然气管道小孔径泄漏后,在环境风速8 m/s时,泄漏形成的危险区域沿地面向下风向...     

内照射防护

核事故时释放的放射性核素组分复杂,能通过吸入、食入、皮肤进入体内,对人类产生危害。当核电站产生核泄露时,包括裂变产物放射性I131在内的放射性核素可能对人类产生较大危害。     

大气扩散模型的研究进展

为了解大气污染物的扩散规律和污染现状,最终解决环境大气污染问题,对大气污染物扩散模型的研究进展进行了综述。大气扩散模型是一种用来研究大气污染物在大气中(主要是边界层内)输送和扩散问题的物理和数学模型。从大气扩散模型的分类以及发展阶段入手,论述了拉格朗日模型、欧拉扩散模型、箱模型、高斯烟羽模型和烟团的原理和规律,最后分析了大气扩散模型的优缺点。     

天然气泄漏和气站站址选择

分析了天然气站站址选择考虑因素之一－－天然气泄漏对下风向大气浓度的影响，通过建立数学模型，并运用基于统计学理论的高斯扩散模型，以某城市为例，进行了模拟计算。并分析了计算结果，表明，泄漏后的扩散浓度还不足以达到天然气爆炸的极限浓度，因此，该方面可作为站址选择的次要因素考虑，在特殊情况下，站址可不严格位于城市常年主导风向的下风向。     

单晶硅太阳电池发射极的模拟优化

针对传统p型衬底晶硅太阳电池,通过PCID数值计算,模拟了发射极扩散峰值浓度、方块电阻、结深等对电池性能的影响规律以及该规律与硅衬底电阻率之间的依赖关系,分析了其中所蕴含的作用机理.对于磷原子浓度梯度符合余误差分布的发射极,得到扩散制结的标准为:扩散峰值浓度介于1×10~(19)～5×10~(19)cm~(-3)之间,方块电阻在100Ω/□以上.尽管电池效率在衬底电阻率为1Ω·cm时最高,并随衬底电阻率的增大而明显下降,但上述发射极扩散标准基本保持不变.     

Dispersion and behavior of hydrogen for the safety design of hydrogen production plant attached with nuclear power plant

Development of nuclear energy and hydrogen energy both as renewable energy open up a vast range of prospects. The scheme for hydrogen generation station in nuclear power plant has been carried out in china. However, Nuclear Energy is expected to encourage a safety culture that prevents serious accidents while dispersion of hydrogen from a container produces a risk of combustion. The dispersion and behavior of hydrogen production plant attached with nuclear power plant are still poorly understood. In this paper, a dispersion of hydrogen model is established and is calculated under two typical condition with corrected ideal gas state equation. The flammability of hydrogen after dispersion is studied. The range of flammability of dispersion of hydrogen production plant with different pressures, positions and temperatures is obtained. This work could contribute to the marginal hydrogen safety design for hydrogen production station and lay the foundation for the establishment of a safe distance standard that it's necessary to prevent hydrogen explosion.     

Development and application of virtual nuclear power plant in digital society environment

Research and development of safe and efficient nuclear energy systems is imperative, since nuclear safety is the key issue in the development of nuclear energy, and it is also the premise of nuclear energy development learned from the painful lessons in history. Advanced numerical simulation can restore the complex physical processes as much as possible and predict system behavior and safety performance, and it facilitates accurate design and assessment. International research in nuclear safety simulation has developed from single physical phenomena simulation to coupling simulation with digital reactor and to comprehensive simulation with virtual nuclear power plant by integrating environmental and social information. Compared with digital reactor, virtual nuclear power plant pays more attention to the evolution of reactor accidents, such as large‐scale physical and social behavior simulation, which concerned the relationship between nuclear safety and environment, as well as the relationship between the nuclear safety and the public. FDS Team proposed “nuclear informatics” firstly by combining nuclear science and informatics and has developed the virtual nuclear power plant in digital society environment Virtual4DS, where many key technologies are developed under the guidance of nuclear informatics, such as integration cloud architecture, automatic accurate modeling, multiphysics coupling simulation, multidimensional information visualization and virtual simulation, and nuclear big data. Virtual4DS has been widely used in the nuclear power plant, nuclear weapons, well logging, etc.     

船用核汽轮机装置仿真研究

建立了适合船用核汽轮机装置实时仿真分析计算的两相流仿真模型。利用该仿真模型对快速变负荷工况下船用核汽轮机装置的动态特性进行了计算分析。结果表明,该模型能准确模拟核汽轮机装置的变负荷运行特性,满足核动力二回路系统实时仿真分析要求。模型已经成功应用于两型船用核动力训练模拟器的开发,对操纵人员的培训及操作规程的验证具有重要意义。     

A comparative institutional analysis of the Fukushima nuclear disaster: Lessons and policy implications

This paper analyzes the causes, responses, and consequences of the Fukushima nuclear power plant accident (March 2011) by comparing these with Three Mile Island (March 1979) and Chernobyl (April 1986). We identify three generic modes of organizational coordination: modular, vertical, and horizontal. By relying on comparative institutional analysis, we compare the modes' performance characteristics in terms of short-term and long-term coordination, preparedness for shocks, and responsiveness to shocks. We derive general lessons, including the identification of three shortcomings of integrated Japanese electric utilities: (1) decision instability that can lead to system failure after a large shock, (2) poor incentives to innovate, and (3) the lack of defense-in-depth strategies for accidents. Our suggested policy response is to introduce an independent Nuclear Safety Commission, and an Independent System Operator to coordinate buyers and sellers on publicly owned transmission grids. Without an independent safety regulator, or a very well established “safety culture,” profit-maximizing behavior by an entrenched electricity monopoly will not necessarily lead to a social optimum with regard to nuclear power plant safety. All countries considering continued operation or expansion of their nuclear power industries must strive to establish independent, competent, and respected safety regulators, or prepare for nuclear power plant accidents.     

结合福岛核事故探讨IAEA核电厂设计安全要求

日本福岛核事故后,为确保核电安全发展,我国提出按全球最高安全要求新建核电项目。国际原子能机构2012年最新出版的核安全要求SSR-2/1《核电厂安全:设计》(Safety of Nuclear Power Plants: Design)是国际权威的、先进的核电厂设计安全要求文件。研究SSR-2/1可用于指导我国核电厂的安全设计,提升其安全水平。介绍了SSR-2/1的升版过程,具体分析SSR-2/1与其上一版本NS-R-1(2000年)在格式和内容方面的变化。对设计安全要求提高的部分,从设计安全性、寿期内电厂设计完整性、基本安全功能增加乏池排热功能、设计扩展工况与严重事故、场外服务最大延长时间以及场址上的若干机组同时发生事故等六个方面,结合福岛核事故后的经验教训进行重点分析和评价。     

我国滨海核电厂海啸防护探讨

  [目的]  我国在建及在运核电厂多为滨海厂址，根据以往观测数据及分析，防洪设计多以风暴潮作为控制性条件，海啸相关研究成果较少，构筑物对海啸的防护方法方面缺少工程经验。福岛核事故后，海啸对核电厂安全的影响受到了核安全监管、核电从业者及公众的广泛关注，国内也开展了对在运核电厂海啸防护水平的复核。  [方法]  结合海啸的特点，针对我国滨海核电厂并以某一核电厂为例，通过海啸波物理模型试验研究工作，以此开展对核电厂海啸防护的复核工作。  [结果]  模型试验研究表明，在海啸波作用下，我国已建滨海核电厂厂坪标高的设置对于近地海啸防护裕度较为充裕。  [结论]  结合现有海域防洪措施，针对后续新建的滨海核电厂设计中需结合厂址条件进一步考虑对于马尼拉、琉球海沟可能产生地震海啸的防护，以增大安全裕度。     

用于动力设备的纳米镍基合金微观结构及耐磨性研究

阀门是核电站应用最多的一种设备,因材料耐磨性不足导致阀门失效是核电站事故的主要原因之一。文中提出在阀门零件的关键密封表面镀上一层纳米镍基合金,可以大大提高阀门的耐磨性,是减少核电站事故的有力手段。应用X射线衍射、TEM研究了纳米镍基合金的组织结构及相结构,陈述了这种结构为什么具有优异耐磨性的机理。     

核电站安全壳在外来事件作用下的安全防护性能研究进展

核电站安全壳是核反应堆的最后一道屏障,其结构的安全性直接关系到核电站周围人员和环境的安全问题。介绍了核电站安全壳的功能及其分类,基于核电站安全壳特殊的防护功能要求,对安全壳结构在地震、飞机撞击和爆炸等外来事件作用下的安全防护性能进行了探讨,并对安全壳结构防护措施的改善给予了相应建议。     

Nuclear power risks in the United States: Shortened version of a paper presented in Detroit by N.C. Rasmussen, Massachusetts Institute of Technology, Department of Nuclear Engineering, Cambridge, Massachusetts

During the summer of 1972 the Atomic Energy Commission authorized the Reactor Safety Study to determine the risks to the public from accidents in large water cooled nuclear power plants of the type being installed in the USA today. This study was to complement WASH-1250 which had examined the safety of other parts of the fuel cycle. The primary goal of the Reactor Safety Study was to determine both the probability and consequences of power plant accidents having possible public effects. The results of that study were released in draft form on 20 August 1974 in document WASH-1400. This paper is a brief summary of some of the most significant results of that study.

The project was under the direction of the author. Mr Saul Levine of the US, AEC was project staff director. It was carried out with a staff of about 60 people and with support from industry, national laboratories, and universities. The total budget was about 3 million dollars.

The project was directed towards the seven major tasks described below.     

严重事故下内陆核电水资源安全应对措施

  [目的]  文章旨在论证严重事故下内陆核电厂具有可靠的水资源安全应对措施。  [方法]  通过对比内陆核电放射性废液处理结果与国家相关标准,分析了严重事故工况下内陆核电的放射性废液的处理措施,同时提出了进一步提高安全性和可靠性的措施—加强备用电源、备用水源和增加废液存贮水池。  [结果]  结果证明:严重事故下,通过安全壳包容、核岛厂房滞留、水池暂存三道外层的放射性物质隔离措施,能够将放射性物质在厂内进行“存贮、封堵和处理”。  [结论]  CAP1000内陆核电具有完善的严重事故预防和事故缓解措施,能够从设计上实际消除大量放射性物质释放的可能性,有能力在严重事故下确保水资源安全。