Probabilistic Approach of Coastal Defense Against Typhoon Attacks for Nuclear Power Plant

With the global warming and sea level rising, it is widely recognized that there is an increasing tendency of typhoon occurrence frequency and intensity. The defenses code against typhoon attacks for nuclear power plant should be calibrated because of the increasing threat of typhoon disaster and severe consequences. This paper discusses the probabilistic approach of definitions about ＂probable maximum typhoon＂ and ＂probable maximum storm surge＂ in nuclear safety regulations of China and has made some design code calibrations by use of a newly proposed Double Layer Nested Mtdti-objective Probability Model （DLNMPM）.

Transient Analysis of Steam Generator in PWR Nuclear Power Plant

The water level control system of steam generator in a pressurized water reactor of nuchear power plant plays an important role which effects the water level control of the steam generator are due the reverse dynamics behavior,so the transient analysis of the steam generator should firstly solve their mathematical models.For determination of dynamic behavior and design and testing of the control system, a nonlinear math model is developed using one dimensional conservation equations of mass,momentum and energy of primary and secondary sides of the steam generator. The nonlinear model is verified with standard power plant data available in the references, then the steady states and transient calculations are performed for full power to 5% power reactor operation of the steam generator of Chinese Qinshan Nuclear Power Plant.

Atmospheric Dispersion and Deposition of Radionuclides (¹³⁷Cs and ¹³¹I) Released from the Fukushima Dai-ichi Nuclear Power Plant

The Lagrangian Particle Dispersion Model (LPDM) in the 594 km× 594 km model domain with the horizontal grid scale of 3 km×3 km centered at a power plant and the Eulerian Transport Model (ETM) modified from the Asian Dust Aerosol Model 2 (ADAM2) in the domain of 70° LAT × 140° LON with the horizontal grid scale of 27 km×27 km have been developed. These models have been implemented to simulate the concentration and deposition of radionuclides (137Cs and 131I) released from the accident of the Fukushima Dai-ichi nuclear power plant. It is found that both models are able to simulate quite reasonably the observed concentrations of 137Cs and 131I near the power plant. However, the LPDM model is more useful for the estimation of concentration near the power plant site in details whereas the ETM model is good for the long-range transport processes of the radionuclide plume. The estimated maximum mean surface concentration, column integrated mean concentration and the total deposition (wet+dry) by LPDM for the period from 12 March to 30 April 2011 are, respectively found to be 2.975 × 102 Bq m-3, 3.7 × 107 Bq m-2, and 1.78 × 1014 Bq m-2 for 137Cs and 1.96 × 104 Bq m-3, 2.24 × 109 Bq m-2 and 5.96 × 1014 Bq m-2 for 131I. The radionuclide plumes released from the accident power plant are found to spread wide regions not only the whole model domain of downwind regions but the upwind regions of Russia, Mongolia, Korea, eastern China, Philippines and Vietnam within the analysis period.

Tsunami Impacts on Nuclear Power Plants along Western Coast of India Due to a Great Makran Earthquake: A Numerical Simulation Approach

The major seismicity source in the northern Arabian Sea is the Makran Subduction Zone (MSZ) that defines the tectonic boundary between the Arabian plate and the Eurasian plate, located offshore Iran and Pakistan over which an instrumentally registered earthquake (Mw 8.1) generated a tsunami on 27 November, 1945. It has caused severe cataclysm to a vulnerable population along the surrounding coastlines, including India. It has been on a long seismic quiescence since this last event. The population and industrialization have exponentially increased along the coastal areas in last half decade. The highly exposed coastal locations to the tsunamis are the areas where the nuclear power plants are located. In the present work, a numerical simulation of a great tsunamigenic earthquake (M 9) is presented that predicts the generation, propagation, run-up and travel time using TUNAMI N2 for estimating tsunami impacts along the nuclear power plants of the western coast of India. TUNAMI N2 code was designed for shallow water wave equations, which uses the finite-difference method based on staggered-leap frog scheme. Thus, it has potential to simulate a far-field tsunami with much more accuracy than other methods. It is observed that the tsunami will strike along the coast of Jaitapur Nuclear Power Plant (Maharashtra), Tarapur Nuclear Power Plant (Maharashtra), Kaiga Nuclear Power Plant (Karnataka) and Mithi-Virdi Nuclear Power Plant (Gujarat) after 210, 215, 225 and 230 minutes, respectively. Results show that the tsunami run-up is highest for Jaitapur coast (2.32 m). The Mithi-Virdi coast is the least effected (0.93 m) while Kaiga (2.15 m) and Tarapur coast (2.12 m) might have faced quite intense tsunami consequences. The arrival times and run-ups of the tsunami along the coast of different power plants have been calculated since these parameters are of vital importance in mitigation of the coastal hazard, evacuation planning and installation of early warning system in order to save the inhabited communities from the disaster.

Violation of the Convention on the Protection of the Black Sea against Pollution,Bucharest’s Convention of 1992 and the Sofia Protocol of 2018 by Turkish Government’s Sinop Nuclear Power Complex Project

On September 12th,2020,the Turkish Ministry of Environment and Urban Planning issued a final approved version of an EIA(Environmental Impact Assessment)report for the Sinop(4,800 MWe)nuclear power plant and nuclear fuel fabrication complex project,located on Turkey’s Southern Black Sea coastline,in the Sinop Providence,which will be built on a BOO(Build-Own-Operate)basis by an offshore company known as General Directorate of Electricity Generation Inc.(EUAS)International ICC,along with unknown shadowy partners and investors.This project violates the Convention on the Protection of the Black Sea against Pollution,namely,Bucharest’s Convention of 1992,and the Sofia Protocol of 2018 which are established to preserve the uniqueness of the Black Sea,sustain the fisheries,and protect marine life.The Black Sea is the largest anoxic water basin in the world with oxygen rich surface waters supporting marine life which constitute only about 13% of the Black Sea volume.For the rest of the entire Black Sea at a depth greater than 150-200 m,there is a permanent hydrogen sulphide zone devoid of life,the oxygen is completely absent after this level.This unique bio-hydrological characteristic has been regulating the preconditions of its following distinctive biodiversity for thousands of years.The biologically rich regions are only limited to only oxygen rich shelf zones,with depths of up to 50-100 m in the southern coast line,and in the northern Black Sea shallow-water areas with depths of up to 5-10 m.This water body,bordering the hydrogen sulphide zone,is approximately 200-300 m wide and averages 5-50 m deep,in which high concentrations of fish eggs and larvae strive,and circulate counterclockwise along 4340 km coastline of the Black Sea.

Twin model-based fault detection and tolerance approach for in-core self-powered neutron detectors

The in-core self-powered neutron detector(SPND)acts as a key measuring device for the monitoring of parameters and evaluation of the operating conditions of nuclear reactors.Prompt detection and tolerance of faulty SPNDs are indispensable for reliable reactor management.To completely extract the correlated state information of SPNDs,we constructed a twin model based on a generalized regression neural network(GRNN)that represents the common relationships among overall signals.Faulty SPNDs were determined because of the functional concordance of the twin model and real monitoring sys-tems,which calculated the error probability distribution between the model outputs and real values.Fault detection follows a tolerance phase to reinforce the stability of the twin model in the case of massive failures.A weighted K-nearest neighbor model was employed to reasonably reconstruct the values of the faulty signals and guarantee data purity.The experimental evaluation of the proposed method showed promising results,with excellent output consistency and high detection accuracy for both single-and multiple-point faulty SPNDs.For unexpected excessive failures,the proposed tolerance approach can efficiently repair fault behaviors and enhance the prediction performance of the twin model.

基于SEM-AHP方法的核电厂定量人为因素评价研究

文章基于人为因素分析与分类系统,分析了115起核电厂执照运行事件报告(Licensed Operation Event Report,LOER),并对影响核电厂事件发生的人为因素进行分类,采用结构方程模型方法得出各影响因素的路径系数,两两比较得到层次分析模型的判断矩阵,进而确定各因素的权重。同时对核电厂人为因素的重要性做排序分析,找到核电厂运行过程中的安全管理薄弱环节,从而促进核电厂系统平稳运行。

基于霍尔三维结构理论的化学控制计算软件的开发

在核电厂中化学控制计算与机组反应性控制、设备管道腐蚀以及机组运行寿命等方面有着重要联系,通过开发并使用程序化计算软件可有效提高计算准确率、缩短工时以及降低人因失误,进一步提升化学精细化控制水平。根据霍尔三维结构模型,从逻辑维、时间维和知识维角度分析软件开发过程,将化学科学专业知识与软件开发和系统管理相融合,形成一套完整的软件开发方法。软件开发大大提升了化学控制智能化水平,有效保证机组长期、稳定、安全地运行。

热核聚变发电厂储能系统运行模式研究

[目的]核聚变作为一种新型核能利用形式,其清洁绿色特性被视为人类未来的“终极能源”,也是我国在能源发展道路上的必经之路。在热核聚变发电厂中,中国聚变工程实验堆(CFETR)聚变反应堆具有一定周期性、脉冲式的输出特性,而汽轮发电机组的运行是稳定、连续的,因此核岛和常规岛之间需配有储能岛以进行储能缓冲;为实现其储能缓冲的功能,储能系统需选择合适的运行模式。[方法]核岛与常规岛耦合运行或解耦运行,对应着储能系统不同的运行模式;文章基于CFETR核岛侧的功率输出特性,从系统配置、设备选型和运行控制等方面对储能系统运行模式的不同方案进行分析和对比。[结果]研究结果表明,核岛与常规岛的解耦运行模式在常规岛发电效率、设备设计技术成熟性和机组运行控制上都更具优势,因此推荐热核聚变发电厂储能系统采用解耦运行模式。[结论]储能系统解耦的运行模式方案大都采用成熟技术,可进行规模化的商业应用,因此可为实现热核聚变发电厂的商业化设计提供支撑。

基于遗传算法的核电备件库存模型仿真优化

备品备件是核电厂设备检修的物质基础,然而持有过量的备件库存将增加核电厂运营成本,通过设置合理的备件库存参数,在保障供应和控制库存之间寻找到一个合理的平衡点。针对核电备件库存参数设置问题,将遗传算法引入备件库存参数优化领域。通过建立核电备件库存参数评价方法,将核电备件库存参数设置转换为多变量优化问题,使用遗传算法计算最优库存参数。选用大亚湾核电厂的备件进行仿真测试,当给备件增加多种领用波动时,使用遗传算法计算的备件库存参数均优于当前数据库中的库存参数,结果表明遗传算法应用到备件库存参数优化领域具有重要的实用价值。

高温高压水管道热疲劳试验设计与数值模拟

核电厂压力容器启停堆和正常运行时,温度压力会在一定范围内发生波动,随着波动次数的增加,会对设备和管道造成严重疲劳损伤。依托北京某高校高温高压腐蚀实验站亚临界水汽环境结构材料试验装置双回路,设计了一种承压管道高通量热疲劳试验方法。基于该试验方法,完成了瞬态水温变化对管道疲劳裂纹扩展的影响研究。结果表明,疲劳裂纹扩展速率随冷却速率降低而逐渐降低。结合有限元数值模拟和三维裂纹扩展分析软件建立了阶梯管道结构的热疲劳裂纹扩展速率模型,并用试验结果对模型进行了修正。

核电厂动力机器模型基础动力参数测试的优化

核电厂汽轮机厂房多位于坚硬的岩石地基上,模型基础动力参数测试共振频率达到100 Hz以上,土质地基上常用的测试方法由于其机械式激振器扰频上限低的缺陷,对核电厂岩石地基适用性很差。在激振器、垫层、激振器与模型基础的连接方式、测试方式等方面进行研究,优化、改进了测试设备和测试方法,开发了全自动常扰力测试控制系统,使之更适合核电厂岩石地基,测试结果更准确地代表岩石地基的动力特性。

核电厂地下管网结构化数据建模研究

在数字化设计平台建设过程中,为了解决缺少专业设计软件的情况下少量地下管网模型的生产和集成问题,需要建立一种与设计软件解绑的建模方式。通过研究使用结构化的管网数据驱动生成三维模型的方法,实现核电厂已有地下管道和管道附属物快速逆向建模,进一步实现核电厂室外工程设计模型和施工模型的集成与应用。

核电厂常规岛射线探伤对蒸汽厂房的辐射影响

由于核电站常规岛厂房设计的特殊性,地面以上厂房的大部分外墙由钢板搭建,加上厂房内管道和设备布置复杂,因此,射线探伤对蒸汽厂房区域的辐射影响较复杂。分析常规岛射线探伤对蒸汽厂房的影响,并提出了防护对策。

核电厂人因培训及评估体系的构建与应用

人因失误对核安全的影响越来越受到重视,全球核电行业总结并推广了系统化培训方法(SAT),以满足行业对人员培训的要求。在实践中,核电企业基于SAT方法建立了核电人因培训体系,包含需求分析、大纲设计、教材开发、培训实施和效果评估流程,其中培训效果评估环节缺少有效手段,导致人因培训体系难以持续改进。本文基于核电厂人因培训的对象、内容、方法和管理需求,以柯克帕特里克四层模型为理论依据,完善了核电厂人因培训体系中效果评估部分,包含了评估流程、工具和方法;并以某核电厂运行处室实践验证了评估体系的应用效果,最后结合当前技术进展提出了继续改进人因培训及评估体系的建议。

核电站安全壳打压试验泄压速率优化研究

核电站安全壳打压试验是机组大修期间的绝对关键路径工作,试验执行质量影响机组大修的总体进度。其中泄压速率作为决定安全壳打压试验工期的重要因素,通过建立核电站安全壳内外结构仿真模型,对25 kPa/h泄压速率时安全壳结构的安全性进行分析,提出泄压速率提升的理论依据,同时将模拟数据与缩尺安全壳模型进行对比验证,旨在为安全壳打压试验全面优化提供技术指导。

长周期地震动作用下某EPR核电站安全壳的隔震性能分析

核电站安全壳是切实有效保证核电站安全的必备设施。研究长周期地震动作用下的安全壳隔震性能,对安全壳具有十分重要的理论意义和工程应用价值。以某EPR核电站安全壳为研究模型,考虑了该安全壳自重和预应力系统,采用软件ANSYS建立复杂的三维数值仿真模型,探讨长周期地震动作用下安全壳的变形、加速度、基底剪力和预应力筋的平均应力,证实在长周期地震动作用下,该安全壳受力性能良好,并在控制范围内。基于此,引入层叠橡胶隔震器和软钢隔震器并联的新型隔震装置,进而研究长周期地震动作用下安全壳的隔震性能。分析结果表明:由于地震动的特性(例如,随机性、不确定性、空间相关性等),核电站安全壳设计必须从多方面重视长周期地震动。短周期地震动作用下新型隔震装置是有效的,长周期地震动作用下隔震失效。研究结果为核电站安全壳隔震设计提供技术指导。

Short-term emergency response planning and risk assessment via an integrated modeling system for nuclear power plants in complex terrain

Short-term predictions of potential impacts from accidental release of various radionuclides at nuclear power plants are acutely needed, especially after the Fukushima accident in Japan. An integrated modeling system that provides expert services to assess the consequences of accidental or intentional releases of radioactive materials to the atmosphere has received wide attention. These scenarios can be initiated either by accident due to human, software, or mechanical failures, or from intentional acts such as sabotage and radioIogicaI dispersal devices. Stringent action might be required just minutes after the occurrence of accidental or intentional release. To fulfill the basic functions of emergency preparedness and response systems, previous studies seldom consider the suitability of air pollutant dispersion models or the connectivity between source term, disper- sion, and exposure assessment models in a holistic context for decision support. Therefore, the Gaussian plume and puff models, which are only suitable for illustrating neutral air pollutants in fiat terrain conditional to limited meteorological situations, are frequently used to predict the impact from accidental release of industrial sources. In situations with complex terrain or special meteorological conditions, the proposing emergency response actions might be questionable and even intractable to decision- makers responsible for maintaining public health and environmental quality. This study is a preliminary effort to integrate the source term, dispersion, and exposure assessment models into a Spatial Decision Support System （SDSS） to tackle the complex issues for short-term emergency response planning and risk assessment at nuclear power plants. Through a series model screening procedures, we found that the diagnostic （objective） wind field model with the aid of sufficient on-site meteorological monitoring data was the most applicable model to promptly address the trend of local wind field patterns. However, most of the hazardous materials being released into the environment from nuclear power plants are not neutral pollutants, so the particle and multi-segment puff models can be regarded as the most suitable models to incorporate into the output of the diagnostic wind field model in a modern emergency preparedness and response system. The proposed SDSS illustrates the state-of-the-art system design based on the situation of complex terrain in South Taiwan. This system design of SDSS with 3- dimensional animation capability using a tailored source term model in connection with ArcView~ Geographical Information System map layers and remote sensing images is useful for meeting the design goal of nuclear power plants located in complex terrain.

核电厂调试阶段仪控系统隐患分析方法研究

仪控系统是核电厂的神经和大脑,对于核电厂的安全、高效运行起着至关重要的作用。仪控系统中容易潜藏一些未能在工厂测试期间发现的隐患。这些隐患在运行过程中可能导致核电厂设备的功能劣化甚至系统故障。核电厂仪控系统的调试过程是运行前的关键阶段,在调试过程中及时识别隐患对于保证仪控系统的正常运行具有重要意义。首先,从特定应用环境、特定应用方式、长期动态运行三个维度对隐患的激发原因进行了分析。对其中可能在调试阶段产生、暴露的隐患激发原因进行了筛选。然后,以核电厂仪控系统实际调试过程中发生的隐患为例,建立隐患与环境模型的映射关系模型,并验证模型在调试阶段的有效性。该研究有助于提高调试阶段核电厂仪控系统隐患的识别能力,具有重要的工程意义。