CARR堆反应堆厂房土壤-结构相互作用与楼层反应谱分析

土壤-结构动力相互作用(SSI)分析及楼层反应谱(FRS)计算是中国先进研究堆(CARR)工程抗震设计的重要环节.本文采用直接法,通过建立二维土壤-结构共同工作计算模型,并分3个方向进行地震动输入,考虑土壤-结构相互作用对反应堆厂房地震反应进行分析,计算出厂房基础部位和各楼层在不同工况下的地震反应及楼层反应谱.     

基底隔震对核电站反应堆厂房的地震响应影响分析

以某核电站反应堆厂房为研究对象,运用有限元分析软件ANSYS对比分析了极限安全地震动作用下采用基底隔震技术和不采用隔震技术厂房结构的地震响应。结果表明,采用基底隔震后能有效地减小反应堆厂房的水平向楼层反应谱、加速度响应及地震作用;采用基底隔震后厂房整体水平向的位移较大,位移主要集中在筏板基础处的隔震层,厂房结构本身楼层间的相对位移很小,呈现出类似刚体位移的特征;此基底隔震方案在水平向的隔震效果显著,而在竖直向隔震效果不明显。     

三向地震载荷下HTR-10厂房土壤-结构相互作用分析

土壤-结构相互作用（SSI）会影响核电厂厂房的地震响应。本文充分考虑SSI效应的影响,对10 MW高温气冷堆（HTR-10）厂房在三向地震载荷下的响应进行了分析。建立了土壤-结构耦合有限元模型,通过构造人工边界实现对地震波在无限域内传播过程的模拟,并对模型的准确性进行了验证。利用该模型计算了HTR-10厂房的地震响应,并对不同楼层的反应谱计算结果进行了分析。对于水平向反应谱,各楼层的反应谱谱型类似,SSI影响规律基本一致。在竖直方向上,结构的响应特点与楼板自身的竖向频率特性有明显关系,不同楼板的响应差别较大。一般情况下,SSI效应对竖向响应有抑制作用,且随着楼层增加更为明显。当楼板与土壤的固有频率接近时,竖向响应与其他楼层相比会有显著放大。     

核电厂电气厂房地震响应敏感性分析

利用人工地震波生成算法,探讨考虑土壤-结构相互作用的核电厂电气厂房地震响应动力分析模型和计算方法。通过比较楼层反应谱,研究岩土材料参数和载荷的不确定性对结构响应的影响。结果表明:岩土材料参数对核电厂电气厂房地震响应的影响更大,单一岩土材料参数下计算得到的拓宽后的楼层反应谱不能完全包络参数变化带来的地震响应差别。即使最终的反应谱大于或等于各种不同岩土参数下的楼层反应谱,仍有必要对不同岩土参数下的楼层反应谱做包络。     

核电厂房三维有限元模型考虑土-结构相互作用的简化方法

为将集总的半无限地基动刚度等效离散给三维厂房结构的筏板基础,借鉴简化的集中质量厂房模型考虑土-结构相互作用(SSI)分析方法,通过力矩等效,推导三维厂房结构考虑SSI的弹簧-阻尼器等效离散模型,并通过模态分析和动力时程分析验证了此等效离散方法的正确性和合理性。这种第一步求解集总的地基动刚度,然后基于通用的有限元软件在三维厂房筏板基础施加弹簧-阻尼器的方法,相对于其他人工边界法更简便易行,便于工程应用。     

18-5临界装置厂房楼层响应谱计算研究

根据18-5临界装置某机柜抗震试验分析的要求,利用ANSYS大型通用有限元程序,建立临界装置厂房结构的有限元模型。在其地基处输入给定的位移时程,对结构进行动力分析,计算得到厂房结构中机柜位置处的位移时程、加速度时程等力学量。用该关键位置处的加速度时程计算其相应的加速度响应谱,分别给出了运行基准地震(OBE)和安全停堆地震(SSE)作用下该厂房标高3.50 m主控制室位置处阻尼比为2%、4%、5%和7%的楼层响应谱。     

5MW低功率堆堆厂房结构抗震校核

用等效静力分析对5MW 低功率堆堆厂房结构作了抗震校核。根据 IAEA-TECDOC-348的规定计算出各楼层的水平剪力:按我国有关规范进行载荷组合,对重要节点做了强度校核。最后对堆厂房的抗震安全性能作出了评价。结果表明,厂房的关键部位在7度地震下是安全的。     

土-结构体系的相互作用分析

本文简要介绍了土与结构体系的相互作用的概念，及在厂房实例计算中对此作用的分析方法。     

考虑地基岩土参数不确定性的核电厂结构随机地震反应分析

在考虑土-结构相互作用(SSI)效应的情况下,引入随机地震反应分析方法,探讨地基岩土参数的不确定性对核电厂地震响应的影响.基于ANSYS程序,采用常数阻抗法,通过设置边界弹簧和阻尼来考虑地基土的作用,并通过设置弹簧和阻尼参数的不确定性,来模拟岩土动态参数的不确定性.针对某1000MW级压水堆核电站反应堆厂房结构,进行随机地震反应的数值仿真分析,并将随机反应结果与确定论分析结果进行了对比.结果表明,随机分析方法是确定论分析方法的有益补充,二者结合能更合理地反映参数的不确定性对结构地震响应的影响.     

基于拉丁超立方抽样的某核岛厂房概率SSI分析研究

根据美国核电规范 ASCE4-1 6 关于概率土-结构相互作用 (SSI)分析的规定,对某核电厂反应堆厂房进行了基于抽样概念的概率 SSI分析研究,分析中主要考虑了地震输入、场地特性以及构筑物刚度和阻尼等关键变量的不确定性,采用 ASCE4-1 6 中建议的拉丁超立方抽样方法和数量,以及各关键变量的概率物理模型,将基于...     

Models test on dynamic structure–structure interaction of nuclear power plant buildings

A reactor building of an NPP (nuclear power plant) is generally constructed closely adjacent to a turbine building and other buildings such as the auxiliary building, and in increasing numbers of NPPs, multiple plants are being planned and constructed closely on a single site. In these situations, adjacent buildings are considered to influence each other through the soil during earthquakes and to exhibit dynamic behaviour different from that of separate buildings, because those buildings in NPP are generally heavy and massive. The dynamic interaction between buildings during earthquake through the soil is termed here as ‘dynamic cross interaction (DCI)’. In order to comprehend DCI appropriately, forced vibration tests and earthquake observation are needed using closely constructed building models. Standing on this background, Nuclear Power Engineering Corporation (NUPEC) had planned the project to investigate the DCI effect in 1993 after the preceding SSI (soil–structure interaction) investigation project, ‘Model Tests on Embedment Effect of Reactor Building’. The project consists of field and laboratory tests. The field test is being carried out using three different building construction conditions, e.g. a single reactor building to be used for the comparison purposes as for a reference, two same reactor buildings used to evaluate pure DCI effects, and two different buildings, reactor and turbine building models to evaluate DCI effects under the actual plant conditions. Forced vibration tests and earthquake observations are planned in the field test. The laboratory test is planned to evaluate basic characteristics of the DCI effects using simple soil model made of silicon rubber and structure models made of aluminum. In this test, forced vibration tests and shaking table tests are planned. The project was started in April 1994 and will be completed in March 2002. This paper describes an outline and the summary of the current status of this project.     

A case study of the effect of cladding panels on the response of reinforced concrete frames subjected to distant blast loadings

The turbine building is a vital structure within nuclear power plants that houses turbines, moisture separators and electric generators among other important equipment. Turbine buildings are typically frame structures that in most cases have not been designed to resist blast loadings. The authors to determine the dynamic responses of reinforced concrete (RC) frame structures when subjected to distant intense surface loadings caused by explosions carried out a numerical study. The study was extended further to investigate the influence of claddings on frame structures when exposed to blast loadings. A three-dimensional (3D) nonlinear dynamic finite element model was created and utilized to determine the dynamic responses of RC frame structures from both local and global perspectives. It was observed from the results obtained from the finite element (FE) simulations carried out that the dynamic responses of frame structures with claddings were more severe. This is due to the variations in blast forces received by the structure.     

CFETR氦冷固态包层及其辅助系统动态氚输运分析

实现氚自持、建立完整的氚循环系统并保证氚安全是中国聚变工程实验堆(CFETR)的主要目标之一。在CFETR氦冷固态包层及其辅助系统设计过程中,需对系统级氚输运行为进行详细分析,包括氚滞留量、释放量、浓度的动态变化等。基于已建立的动态氚分析程序TriSim-Dynamic,在此基础上进行修改完善,利用该程序对CFETR氦冷固态包层及其辅助系统氚动态输运进行分析模拟,得到了冷却剂及提氚吹扫气中氚浓度、氚分压,管壁及结构材料中氚盘存量,氚通过包层结构材料和辅助系统管壁向真空室、水冷系统及建筑的渗透通量动态变化,并将其稳态值与已进行基准校核的稳态氚分析程序TriSim-SA及理论解析解进行比较,以初步验证分析结果的准确性,数据结果也对CFETR氚安全分析提供了一定的参考。     

Dynamic behaviour of tunnels under impact loads

Safety related structures of a nuclear power plant are often required to withstand the effects of an aircraft impact load. Underground tunnels, carrying cables and pipes between buildings, also belong to this class of structures. For the design of components located inside the tunnels one must know the response of the structure of the connection points of the components. Acceleration response spectra and relative displacements are of major interest. Using finite element techniques in order to idealize the tunnel and the surrounding soil the effects of the various parameters on the dynamic response of the tunnels are investigated.It is found that some of the main parameters which influence the dynamic response of a tunnel are: soil stiffness and layering, depth of embedment and the thickness of the concrete, protective slab. Vertical accelerations are also affected by the stiffness of the tunnel.     

Approximate formulas to calculate the seismic response of light attachments to buildings

Simple approximate formulas are proposed to compute the maximum response of equipment or any other light secondary system attached to buildings subjected to earthquake ground motions. The formulas are derived on the basis of a modified version of the conventional response spectrum method and the consideration of building and attachment as one unit. Notwithstanding, they are expressed in terms of the independent dynamic properties of the two components and ordinates from the response spectrum of a specified ground motion. Secondary systems with multiple degrees of freedom attached to one or two arbitrary points of a supporting multistory structure may be considered. As presented, however, the formulas are restricted to cases in which the independent primary and secondary systems are linear elastic with classical modes of vibration, and the masses of the secondary system are small in comparison with those of the primary one. Their accuracy is verified by means of a comparative study with time-history solutions. In this comparative study, the approximate formulas yield an average error of about 4% and a maximum of about 22%.     

Steel containment resistance under dynamic pressure

Loadings to cause severe accidents on containment buildings can include combinations of uniform internal pressure, dynamic pressure, and seismic. Most studies that have been conducted to predict containment building capacity have focused on the effect of overpressurization on containment performance. A simple methodology that permits rapid and reasonably accurate analysis for assessing the capacity of steel containment buildings due to global or local uniform or spatially varying dynamic loading was developed. An axisymmetric model was used and the circumferential variation of the pressure, displacements, and stress resultants were represented by Fourier series. Shell vibration and buckling analysis were performed using modified versions of BOSOR4 and BOSOR5 finite difference codes. The modified version of BOSOR5 allows the input of pressures that vary along the meridianal direction. These pressures were increased until failure of the containment occurred. Failure was defined to occur when membrane strains reached twice the yield strain or the bifurcation point was introduced. The applicability of this analysis method was verified by analyzing several problems as well as a simplified containment building. The axisymmetric analysis demonstrated a powerful tool to access the capacity of steel containment buildings.     

核反应堆厂房结构楼层反应谱的敏感性分析

以某千兆瓦级压水堆核电站反应堆厂房结构为对象,研究了考虑土一结构动力相互作用的硬土场地条件下地基土动态剪切模量的变化对楼层反应谱计算的影响,定量分析了厂房结构楼层加速度反应谱对地基土动态参数变化的敏感性,从而为评估类似硬土场地条件下核反应堆厂房结构抗震安全性提供了一种可供参考的计算方法。     

Dynamic testing of full-scale nuclear power plant structures and equipment

Three steps are required in the design of reliable nuclear power plants to be located in seismic areas. In addition to development of realistic analytical models, it is necessary to perform dynamic tests to verify the models and acquire the information needed to establish the dynamic parameters for modeling. The third and final step is to perform high level proof tests to validate analysis and test results. This report is an overview of dynamic testing methods.Testing can be performed in the laboratory or in the field. Laboratory tests are useful because a wide range of effects can be studied and test parameters are more easily controlled. Care must be exercised to insure that the laboratory situation faithfully reproduces the actual structure in such details as supports, appurtenances, appendages, and mounting methods. In general, laboratory methods permit high level excitation of structures weighing up to a few metric tons (a few facilities in the world have capabilities up to 100 t). Since actual structures of interest to nuclear power plant designers often weigh up to 10 000 t, field testing is also important. Test procedures have been developed, using portable structural vibrators, for testing structures as large as nuclear power plant containment buildings. High level tests can be performed using explosives buried in the soil to excite structures. Recent work performed by the author demonstrates that explosive tests which produce a predetermined, specified response spectrum can be conducted.     

Construction materials for reactor buildings for decommissioning and recycling

A conceptual fluid–steel structure was studied to investigate the seismic characteristics of its use in the reactor building of nuclear power plants. The results of the earthquake response analysis of the conceptual fluid–steel structure showed that the structure had the same seismic safety ability as conventional reactor buildings. Applying the fluid–steel structure to a rector building, results in the following advantages: more elastic and light weight building materials, reducing the decommissioning wastes; the ability to recycle the structure materials because the fluid in the steel structure can be discharged the steel can be reused easily; the fluid in the steel structure has the possibility of reducing the seismic response of the structure by the sloshing damper effect. Further study is encouraged by this results.     

Soil-structure interaction of nuclear reactor structures considering through-soil coupling between adjacent structures

The theoretical problem concerning the influence of through-soil coupling between adjacent structures on the seismic loading of nuclear reactors has been investigated by considering a soil-structure interaction model in which several three-dimensional flexible structures are bonded to an elastic half-space. These structures, which are allowed to be either similar or dissimilar, are modeled as conventional discrete systems mounted on separate base slabs of close proximity. For the purpose of this study, it is assumed that the stiffness of any structure such as piping connecting the adjacent buildings is negligible.For purposes of comparison, the seismic responses of structural masses are determined both with and without the influence of nearby structures. Both transient and steady-state results are presented and discussed for some typical simplified two- and three-structure complexes. Emphasis is placed on the effects of through-soil coupling on the dynamic response of the system rather than actual magnitudes of response which have previously been treated for plants erected on a single base slab. The significant findings are that nuclear power plants can be designed to achieve a reduction in seismic loads due to interaction with neighboring structures. Conversely, improper plant design and layout may result in mutual reinforcement of resonances with increased loads.