scholarly journals Dynamic seismic analysis of nuclear power plant buildings and bearing stratum

2021 ◽  
Vol 31 (4) ◽  
pp. 79-88
Author(s):  
S. V. Koval ◽  
A. V. Kuzminov ◽  
P. A. Rodin ◽  
N. M. Sidorov
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Seismic Analysis ◽  
Seismic Loading ◽  
Response Spectra ◽  
Kinematic Parameters ◽  
Specialized Software ◽  
Floor Response Spectra ◽  
Calculation Results ◽  
Supporting Frame

Various approaches are used for simulating seismic loading and collaboration of a structure and a bearing stratum when carrying out dynamic seismic analysis in specialized software. In the present work, the kinematic parameters of various structures and bearing stratum were calculated using SCAD and STAR_T software. Seismic performance of a reference tower type supporting frame was calculated for 7 grade earthquake. As a result, the floor accelerograms were calculated, and the floor response spectra were built. The calculation results obtained by various methods and structure models were analyzed and compared.

Reanalysis of the floor response spectra of the Ignalina Nuclear Power Plant Reactor Building

2017 ◽  
Vol 324 ◽  
pp. 260-268
Author(s):  
Gintautas Dundulis ◽  
Rimantas Kačianauskas ◽  
Darius Markauskas ◽  
Eugeniuš Stupak ◽  
Stanislav Stupak ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Response Spectra ◽  
Floor Response Spectra ◽  
Reactor Building ◽  
Plant Reactor

Analyzing and Comparing the Floor Response Spectra of the NPP Based on Different Soil Dynamic Numerical Models

2013 ◽  
Author(s):  
Xiu-yun Zhu ◽  
Rong Pan
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Seismic Design ◽  
Nuclear Power ◽  
Numerical Models ◽  
Response Spectra ◽  
Site Conditions ◽  
Design Codes ◽  
Floor Response Spectra ◽  
Soil Dynamic

The traditional soil dynamic impedance models, recommended by the main international seismic design codes of the nuclear power plant (NPP), are only expressed by a single parallel connection system of spring and dashpot which can not reflect the dynamic stiffness varying with excitation frequencies, and also can not simulate the cases of non-homogeneous site conditions. With the recent development of soil-structure interaction (SSI) analysis, based on the damping-solvent extraction method (DSEM) and the lumped parameter models recommended by seismic design codes of ASCE4-98,RCCG which are all applicable to the homogeneous site and also massless foundation model and viscous-spring artificial boundary model of especially fit for the numerical simulation of non-homogeneous site, comparative study of both the direct method and sub-structure method is carried out in this paper. Finally, by taking the analysis of floor response spectra (FRS) for a certain CPR1000 reactor building as an example, comparative analyses of homogeneous and layered site conditions using various soil dynamic numerical models above-mentioned are performed. In addition, in order to validate the accuracy, the calculated results are compared to that of SASSI program. The results show that FRS in the horizontal direction are good agreement regardless for the homogeneous and layered site conditions, the shapes of FRS in the vertical direction change obviously in the homogeneous site condition. This paper provides some guidance and reference in the aspect of evaluation the seismic suitability for the site of nuclear power plant (NPP).

A Less-Conservative Approach to Simplified Seismic Analysis for Small Bore Nuclear Piping System

2014 ◽  
Author(s):  
Joon Ho Lee ◽  
In Yeung Kim
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Seismic Analysis ◽  
Response Spectra ◽  
Piping System ◽  
Successful Implementation ◽  
Conservative Approach ◽  
Analysis Method ◽  
Support Design ◽  
Floor Response Spectra

Per guidelines for piping system reconciliation such as EPRI NP-6628 (NCIG-14), simplified seismic design methods have been used by nuclear piping designers to deal with small bore piping for many years. These methods are generally based on enveloping the results of rigorous dynamic or conservative static analysis. Small bore piping is generally more flexible with larger margin in support design comparing to large bore piping. Consequently, Classes 2 & 3 piping less than 2-1/2 inch NPS that is analyzed by a conservative “cookbook method” is excluded from the as-built verification actions in IE Bulletin 79-14. The ASME code’s Subsection NF and B31.1 provide recommended pipe spans by pipe size considering only piping weight; therefore, the seismically qualified piping span must be developed for the peak acceleration of the applicable amplified or floor response spectra. Simplified seismic analysis method being considered for the Korean nuclear power plants is based on the Load Coefficient Method provided in Appendix N-1225 of ASME Section III. However, since the simplified analysis method involves conservative and enveloping approach in an effort to comply with applicable requirements and results in an excessive number of supports and unrealistically high support loads, the successful implementation largely depends on how the issues related to the excessive conservatism are resolved when determining allowable pipe spans and support design loads of the piping system. In this paper, simplified engineering equations are presented as a less-conservative approach based on a detailed computer analysis method, which is alternative to the various handbooks and design charts that are based on the conventional hand calculation method.

Inclusion of Aircraft Crash into NPP Design Bases and Probabilistic Justification of Loads on Civil Structures and Equipment

2020 ◽  
pp. 35-47
Author(s):  
Nikita Chernukha
Keyword(s):  
Nuclear Power ◽  
Response Spectra ◽  
Mechanical Action ◽  
Exceedance Probability ◽  
Civil Structures ◽  
Method Of Calculation ◽  
Floor Response Spectra ◽  
Aircraft Trajectory ◽  
Probabilistic Justification ◽  
Aircraft Crash

The article is about nuclear power plant (NPP) safety analysis in case of aircraft crash. Specifically, the article considers the following problems: inclusion of aircraft crash into NPP design bases regarding calculation of frequency of an aircraft crash into NPP; aspects of justification of loads on NPP structures, systems and components (SSCs) caused by mechanical action of a primary missile – aircraft fuselage impact. Probabilistic characteristics of such random parameters as frequency of aircraft crash and direction of aircraft trajectory are determined by the results of analysis of world statistics of aviation accidents. Method of calculation of aircraft crash frequency on structures, buildings and NPP as a whole is presented. It takes into account options of accidental and intentional aircraft crashes and various aircraft approach scenarios. Procedure of probabilistic justification of loads on civil structures under aircraft impact is described. The loads are specified so as not to exceed allowable value of failure probability of NPP as a whole. Calculation of failure frequency of civil structures of existing NPP is given as an example to show analysis in case of a crash of an aircraft heavier than considered in NPP design. Procedure of probabilistic justification of dynamic loads on NPP equipment in case of aircraft impact is described. Method of floor response spectra (FRS) calculation with the required non-exceedance probability is given. Probabilistically justified loads in case of intentional aircraft impact (act of terrorism) are also considered. Additionally it is presented how internal forces calculated with the use of FRS with the required non-exceedance probability can be summed to provide analysis of subsystems.

The Severe Accident Analysis of CPR1000 Based on MELCOR Code

2013 ◽  
Author(s):  
Longze Li ◽  
Mingjun Wang ◽  
Wenxi Tian ◽  
Guanghui Su ◽  
Suizheng Qiu
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Failure Time ◽  
Water Pressure ◽  
Severe Accident ◽  
Feed Water ◽  
Calculation Results ◽  
Station Blackout ◽  
Accident Response ◽  
Basic Standard

The severe accident of CPR1000 caused by station blackout with the SG safety valve failure is simulated and analyzed using MELCOR code in this work. The CPR1000 power plant severe accident response process and the results with three different assumptions, which are no the seal leakage nor the auxiliary feed water, the seal leakage and auxiliary feed water exist, the seal leakage exist but no auxiliary feed water separately, are analyzed. According to the calculation results, without the seal leakage and auxiliary feed water, pressure vessel would fail at 9576 s. When auxiliary feed water was supplied, pressure vessel’s failure time would delay nearly 30000s. When the seal leakage exists, pressure vessel’s failure time would delay about 50 s. The results are meaningful and significant for comprehending the detailed process of severe accident for CPR1000 nuclear power plant, which is the basic standard for establishing the severe accident management guideline.

Direct generation of floor design spectra (FDS) from uniform hazard spectra (UHS) — Part I: formulation of the method

2020 ◽  
Vol 47 (12) ◽  
pp. 1372-1386 ◽  
Author(s):  
Amin Asgarian ◽  
Ghyslaine McClure
Keyword(s):  
Seismic Analysis ◽  
Three Dimensional ◽  
Response Spectra ◽  
Ambient Vibration ◽  
Uniform Hazard Spectra ◽  
Design Spectra ◽  
Floor Response Spectra ◽  
Response Amplification ◽  
Direct Generation ◽  
Ambient Vibration Measurements

In most current building codes, seismic design of non-structural components (NSCs) is addressed through empirical equations that do not capture NSC response amplification due to tuning effects with higher and torsional modes of buildings and that neglect NSC damping. This work addresses these shortcomings and proposes a practical approach to generate acceleration NSC floor design spectra (FDS) in buildings directly from their corresponding uniform hazard spectra (UHS). The study is based on the linear seismic analysis of 27 reinforced concrete buildings located in Montréal, Canada, for which ambient vibration measurements (AVM) are used to determine their in situ three-dimensional dynamic characteristics. Pseudo acceleration floor response spectra (PA-FRS) are derived at every building floor for four different NSCs damping ratios. The calculated roof FRS are compared with the 5% damped UHS and a formulation is proposed to generate roof FDS for NSCs with 5% damping directly from the UHS.

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