核岛屏蔽厂房钢板混凝土等效模型研究

为了抵御大型商用飞机的恶意撞击,核电站核岛屏蔽厂房的外墙通常设计为钢板混凝土结构,但是由于钢板混凝土在结构形式上较为特殊,常会给设计和审评中的有限元分析计算带来困难。针对实际核电厂核岛屏蔽厂房中的钢板混凝土结构,分别采用单一截面法和分层壳单元法进行模拟,研究分析两种等效方法各自的适用性。结果表明:单一截面法和分层壳单元法均能够有效模拟钢板混凝土的结构形式,并且两种方法各有优点,其中单一截面法在建模和计算上较为便捷,易于操作;而分层壳单元法能够较为细致的分析查看钢板混凝土内部钢板与混凝土各层间的应力分布情况,从而更好的把握屏蔽厂房的安全性。     

岭澳核电站核岛施工塔机布置及选型

岭澳核电站于 1996年 12月底签定承建合同 ,该工程与大亚湾核电站工程基本相同 ,两台 98万ｋＷ发电机组 ,土建部分主要为钢筋混凝土构筑件 ,钢筋总量 2 6 70 0ｔ,混凝土量 2 6万多ｍ3,主体施工进度要求为 2 2个月。核岛土建工程各建筑物均为现浇钢筋混凝土结构 ,平面布置十分紧凑。核岛工程占地长 180ｍ、宽 110ｍ ,需建造两座反应堆厂房、两个核燃料厂房、两个电气厂房和一个核辅助厂房等十七座厂房 ,各厂房彼此相连 ,中间无空隙 ,无水平通道伸入其中。施工所需原材料、半成品、成品以及施工机具全部靠塔机空中吊运 ;混凝土浇注主要用混凝…     

核电站核岛施工中的模板种类

核电站工程几乎全部采用现浇钢筋混凝土结构（也有极少量的预制混凝土）。在大亚湾和岭澳核电站施工中 ,从模板体系选择、模板设计到制作和支设 ,均给予特别重视。本文介绍大亚湾及岭澳核电站使用的几种模板。１核电站的工程特点大亚湾及岭澳两座核电站核岛各厂房的外墙均为清水混凝土 ,模板拆除后稍加修补 ,不做任何装饰 ,连建筑物的装饰线条均在混凝土施工时做好。各厂房的内墙面也不抹灰 ,混凝土表面稍加修补后满刮腻子 ,再刷油漆。核电站核岛各厂房均为多层墙板混凝土结构 ,层高不等 ,形状多样 ,有圆柱形、多边形和曲线形等。现浇的墙板…     

大型商用飞机撞击核安全壳破坏效应的数值模拟

采用飞射物-目标相互作用分析方法模拟分析大型商用飞机撞击核安全壳破坏效应,通过现场三维激光扫描技术与《飞机结构维修手册》的信息采用,正、逆向建模相结合的手法,创建了飞机精确模型,得到详细的飞机质量和刚度数据。并对空客A340-300型号商用飞机机型撞击安全壳时可能出现的多个变量分别进行了非线性动力学的数值模拟。分析飞机不同撞击速度、不同撞击高度、不同撞击角度及混凝土不同弹性模量等11个参数下,安全壳在不同工况时的破坏情况。     

核岛构筑物飞机撞击下结构非线性动力分析

APC壳是核电站抵御商用大飞机撞击的主要屏障,采用通用有限元软件LS-DYNA建立商用大飞机以及厂房的有限元模型,对APC壳墙体在大飞机撞击作用下的弹塑性响应进行计算分析,论证了APC壳具有抗大飞机撞击的能力,保护内部厂房免受大飞机撞击的影响。     

核电结构隔震试验研究

隔震技术是目前公认有效的地震控制技术,而地震的不确定性依然是核电站抗震安全的巨大挑战。首先,针对AP1000新型非能动型核电站结构设计了包括安全壳、屏蔽厂房、附属厂房在内的隔震试验模型。其次,对隔震模型进行了模拟振动台试验,试验结果表明,隔震技术能够有效降低核电结构上部的地震响应。最后,对核岛厂房应用隔震技术进行了讨论,表明了隔震装置的应用能够实现设计能力翻倍的目标。     

CPR1000核电厂安全壳撞击试验研究

安全壳是核电厂中防止放射性物质外泄的最后一道屏障。为研究安全壳在飞行物撞击下的响应,以CPR1000核电厂安全壳为研究对象,依据弹性力-重力相似律,设计建造了一个几何比尺为1∶20的仿真混凝土安全壳模型。以小型飞机(新舟600)和大型商用飞机(波音737-800)为原型飞行物,在相同相似关系下以刚性物为模型飞行物来模拟飞机撞击安全壳的模型试验,研究安全壳结构在飞机撞击作用下的动力响应、破坏现象和损伤破坏过程。试验结果表明:核电厂安全壳结构在小型飞机撞击作用下会出现局部冲剪破坏,结构能保持弹性完整性;在大型商用飞机的第1次撞击作用下,安全壳会出现大量的宏观裂纹,但整体能保持基本完好,没有出现整体性的破坏和倒塌现象,而在第2次撞击作用下,安全壳则发生倒塌。     

考虑退役要求的核电站核岛厂房设计

核电现已成为我国重要的能源之一,核电站未来的退役不仅工作量巨大、耗资昂贵,并且存在放射性和非放射性两方面的危害。分析核电站的核岛厂房的布置原则,以及核电站退役的初步方案,总结出核岛厂房在设计阶段应提前考虑的退役的特殊要求,为核岛厂房的设计提供参考。     

高温高湿环境核电站核岛筏基整体浇筑温度应变监控

高温高湿环境给核电站核岛筏基混凝土整浇和养护带来诸多困难,尤其是易导致混凝土中心温度过高,内外温差过大,不利于裂缝控制。以某核电站核岛筏基在高温高湿环境下的混凝土浇筑的温度应变监控数据为基础,结合三维有限元数值仿真模型的理论分析结果,对养护期间的混凝土裂缝控制进行深入分析。经有效温度应变监控养护的该筏基混凝土拆模后未出现明显裂缝。此方法为其他核电站筏基混凝土浇筑裂缝控制提供了重要参考依据。     

大飞机撞击钢筋混凝土核安全壳模型试验研究增强出版（附加材料可在文章详情页“评审附件”下载）

美国9·11恐怖袭击事件后,核电厂房抵御大型商用飞机恶意撞击成为核安全领域备受关注的热点问题。为真实准确地研究大飞机撞击下核电厂房结构的损伤破坏及振动特性,基于某新型反应堆核电厂房结构,设计了大飞机撞击钢筋混凝土核安全壳模型试验,获得了核安全壳结构遭受大飞机撞击时相对完整的试验数据及物理参数。试验结果表明：当大飞机模型以我国核电厂厂址选择安全导则中建议的基准速度100 m/s撞击时,安全壳模型发生局部碎甲破坏,但壳体的主筋整体性能完好,钢筋网有效阻止了大飞机模型的侵入破坏。依据试验结果研究了钢筋混凝土安全壳结构在大飞机撞击作用下的损伤破坏规律和特点,分析了结构的撞击振动反应特性。根据试验结果反演至原型结构,安全壳结构的环梁牛腿处和筒体与穹顶连接处峰值加速度较大,分别为39.5g和47.2g,底板处水平和竖向峰值加速度相对较小,但仍达到3.45g和4.37g。壳体直接撞击区钢筋发生屈服,而在壳体碎甲区之外,各测点的钢筋应变均小于屈服应变,钢筋未发生屈服,钢筋混凝土壳体未发生由振动导致的破坏。     

Experimental study on a large aircraft impacting reinforced concrete nuclear containment structure model

美国9·11恐怖袭击事件后，核电厂房抵御大型商用飞机恶意撞击成为核安全领域备受关注的热点问题。为真实准确地研究大飞机撞击下核电厂房结构的损伤破坏及振动特性，基于某新型反应堆核电厂房结构，设计了大飞机撞击钢筋混凝土核安全壳模型试验，获得了核安全壳结构遭受大飞机撞击时相对完整的试验数据及物理参数。试验结果表明：当大飞机模型以我国核电厂厂址选择安全导则中建议的基准速度100 m/s撞击时，安全壳模型发生局部碎甲破坏，但壳体的主筋整体性能完好，钢筋网有效阻止了大飞机模型的侵入破坏。依据试验结果研究了钢筋混凝土安全壳结构在大飞机撞击作用下的损伤破坏规律和特点，分析了结构的撞击振动反应特性。根据试验结果反演至原型结构，安全壳结构的环梁牛腿处和筒体与穹顶连接处峰值加速度较大，分别为39.5g和47.2g，底板处水平和竖向峰值加速度相对较小，但仍达到3.45g和4.37g。壳体直接撞击区钢筋发生屈服，而在壳体碎甲区之外，各测点的钢筋应变均小于屈服应变，钢筋未发生屈服，钢筋混凝土壳体未发生由振动导致的破坏。     

A cross‐scale refined damage evolution analysis of large commercial aircraft crashing into a nuclear power plant

Since the 9/11 attacks, whether nuclear power plants (NPPs) can withstand the malicious impact of large commercial aircraft has become a question that must be considered in the design phase. Refined model and fine‐scale element reflect more accurately the failure procedure and behaviour. However, due to the exceedingly complex structure of NPP, the traditional meshing method requires a substantial number of geometric operations involving point, line, area, and volume, leading to a tedious modelling process and very high computational costs, as well as making it difficult to modify and optimize the model. This paper combines the scaled boundary finite element method with the octree technique to refine nuclear engineering damage evolution analysis and establish a refined numerical model of the Generation III⁺ NPP, considering the detailed equipment hatch, air intake, and internal steel containment vessel structures. Subsequently, the refined damage evolution analysis of a large commercial aircraft crashing into an NPP was developed. The mesh size sensitivity, impact region shape comparison, and the influence of different impact heights were discussed. The results indicate that the cross‐scale refined meshing and analysis method provides a high‐quality discrete grid with fewer elements. Furthermore, this method is highly flexible, more accurately simulating the damage evolution and gradual destruction process. We recommend future structural optimization for the air intake and conducting detailed analyses at this location. The cross‐scale analysis method presented in this paper enables a rapid, refined simulation of a malicious impact by a large commercial aircraft. Additionally, it provides technical support for future studies of the responses of NPPs' internal structures, systems, and equipment under extreme earthquake and other disaster conditions.     

Failure behavior of unbonded bi-directional prestressed concrete panels under RABT fire loading

Although the number of terror-and explosion-related incidents associated with military and terrorist activities is increasing globally, the existing design procedure for civil infrastructures does not consider a protective design for extreme loading scenarios such as blast, impact, and fire loading. Major infrastructure, for example bridges, tunnels, prestressed concrete containment vessels (PCCVs), and liquefied natural gas (LNG) storage tanks are often constructed using prestressed concrete, because it enhances the structural capacity. Concrete is often used as a construction material because of its low thermal conductivity, which makes it a good fire resistant material. However, the fire-resistant behavior of the high-strength concrete (HSC) and prestressing (PS) tendons used in prestressed concrete (PSC) is different than that of ordinary reinforced concrete (RC). Also, there has been limited research comparing PSC to RC under extreme loading conditions. This study presents experimental testing of unbonded bi-directionally prestressed concrete panels with dimensions 1000×1400×300 mm³ that were tested under RABT fire loading to simulate a jet aircraft crash-fire accident. A prestressing force of 430 kN was applied to the PSC specimens using unbonded threaded bars. After a RABT fire test, residual flexural strength tests were performed on the fire-damaged PSC and on RC specimens for comparison. Results of the RABT fire and residual flexural strength tests indicated that the fire-damaged PSC specimens showed severe thermal spalling damage induced by PS relaxation and deterioration of strength/stiffness, respectively. These study results can be used as basic research data for future research in numerical simulation of fire and the design of PSC structures under the fire scenario.     

District-scale simulation for multi-purpose evaluation of urban energy systems

This article presents a simulation model for application to several commercial sector buildings in a particular area to analyse the impact of changes in buildings and building energy systems on the issue domains of mitigation of global warming and heat island phenomena as well as the planning of urban infrastructures for electricity and water. The impact on these issue domains is evaluated using five indicators: primary energy consumption, carbon dioxide emission, sensible anthropogenic heat release, peak electricity demand and water consumption by cooling towers. This article explains the modelling methodology, the simulation model including databases and a case study carried out to demonstrate the simulation capacity of the model. The case study shows that the form and function of buildings influence energy consumption and the five indicators significantly. The trade-off relationship is also shown between the five indicators with respect to changes in the heat-source system of buildings.     

Vulnerability and Robustness of a Security Skyscraper Subjected to Aircraft Impact

Abstract: Ultra‐high‐performance concrete (UHPC) is particularly suitable for application in aircraft‐impact‐resistant high‐rise buildings for combined load‐bearing and protective structures. The material provides very high—steel‐like—compressive strength, sufficient ductility, and fire resistance due to the addition of steel and polypropylene fibers. The following contribution is focused on two key aspects: hydro‐code simulations of structural UHPC walls which protect vertical escape and rescue routes and structural dynamic simulations of the global structure to investigate the impact resistance considering the sudden loss of external columns. A high‐speed dynamic material model for UHPC is obtained by implementing the results of a series of Hopkinson‐Bar experiments which were recently published. The strain‐rate‐dependent material properties are implemented in the established RHT‐Concrete‐Model for hydro‐code applications being furthermore extended by a tensile softening law for fiber‐reinforced UHPC. Based on this material model a series of aircraft‐engine impact experiments are configurated supported by three‐dimensional nonlinear hydro‐code prognosis simulations. With a total of six impact experiments on combined fiber‐ and rebar‐reinforced UHPC panels, all relevant damage states of the structural wall are obtained. The experimental results are compared to the hydro‐code prognosis simulations to validate the simulative approach and the material model for UHPC. In addition to the local impact behavior, structural dynamic numerical simulations of a global high‐rise structure are presented being focused on the effect of the sudden and notional loss of columns in coincidence with the aircraft impact load function.     

核电站安全壳老化机理分析与探测方法

核电站预应力混凝土安全壳结构是核反应堆的最后一道保护屏障,随时间的增长,混凝土材料和预应力系统以及钢构件部分都会发生老化问题。由于安全壳的安全级别、结构形式与使用环境的特殊性,使其老化问题不同于普通结构,存在特殊的导致结构老化的机理。通过对美国核管会(NRC)、国际原子能协会(IAEA)等机构相关资料的调研,结合国内多个核电站安全壳的现场老化探测结果,对核电站安全壳的老化机理进行了分类归纳,分为混凝土材料部分、预应力系统部分与钢构件部分,并对老化机理进行分析,对国内外先进的老化探测手段进行介绍。     

常规装药爆炸荷载作用下核电站安全壳的动力响应分析

根据核电站安全壳的结构形式,采用流固耦合算法,对核电站安全壳在爆炸荷载作用下的动力响应进行了数值模拟,得出了造成安全壳破损的最小安全距离和爆当量。数值模拟结果为核电站的主动拦截防护提供了重要的技术参数。     

爆炸荷载作用下钢筋混凝土柱的动力响应与破坏模式

在爆炸荷载作用下,钢筋混凝土构件和结构的动力响应较之地震荷载和静态荷载作用下要复杂得多。运用有限元显式动力分析软件LS-DYNA,建立了典型钢筋混凝土柱的三维有限元模型,该模型对钢筋混凝土采用分离式建模,并且考虑了材料的应变率效应和钢筋与混凝土间的粘结滑移。在该有限元模型的基础上,通过对爆炸荷载作用下钢筋混凝土柱动态响应的数值模拟,研究了钢筋混凝土柱在爆炸荷载作用下可能的破坏模式及其规律。同时,运用参数化分析方法,研究了截面惯性矩、混凝土轴心抗压强度、纵筋配筋率和配箍率等参数对钢筋混凝土柱在爆炸荷载作用下的动态响应的影响,在数值模拟结果的基础上,分析提出了钢筋混凝土柱抗爆设计时应当注意的问题。研究结果表明:在爆炸荷载作用下,钢筋混凝土柱的破坏模式不仅和自身的特性有关,还取决于爆炸荷载的类型。提高柱截面惯性矩和混凝土轴心抗压强度,能够显著降低钢筋混凝土柱在爆炸荷载作用下的柱中水平位移,从而提高其抗爆性能。增加配箍     

An investigation of ballistic response of reinforced and sandwich concrete panels using computational techniques

Structural performance of nuclear containment structures and power plant facilities is of critical importance for public safety. The performance of concrete in a high-speed hard projectile impact is a complex problem due to a combination of multiple failure modes including brittle tensile fracture, crushing, and spalling. In this study, reinforced concrete (RC) and steel-concrete-steel sandwich (SCSS) panels are investigated under high-speed hard projectile impact. Two modeling techniques, smoothed particle hydrodynamics (SPH) and conventional finite element (FE) analysis with element erosion are used. Penetration depth and global deformation are compared between doubly RC and SCSS panels in order to identify the advantages of the presence of steel plates over the reinforcement layers. A parametric analysis of the front and rear plate thicknesses of the SCSS configuration showed that the SCSS panel with a thick front plate has the best performance in controlling the hard projectile. While a thick rear plate is effective in the case of a large and soft projectile as the plate reduces the rear deformation. The effects of the impact angle and impact velocity are also considered. It was observed that the impact angle for the flat nose missile is critical and the front steel plate is effective in minimizing penetration depth.