Evaluation Method for Seismic Fatigue Damage of Plant Pipeline

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Fumio Inada ◽  
Michiya Sakai ◽  
Ryo Morita ◽  
Ichiro Tamura ◽  
Shin-ichi Matsuura ◽  
...  
Keyword(s):  
Fatigue Damage ◽  
Nuclear Power ◽  
Power Plants ◽  
Evaluation Method ◽  
Response Spectrum ◽  
Damage Mechanism ◽  
Peak Frequency ◽  
Cumulative Damage ◽  
Cumulative Absolute Velocity ◽  
Seismic Index

Although acceleration and cumulative absolute velocity (CAV) are used as seismic indexes, their relationship with the damage mechanism is not yet understood. In this paper, a simplified evaluation method for seismic fatigue damage, which can be used as a seismic index for screening, is derived from the stress amplitude obtained from CAV for one cycle in accordance with the velocity criterion in ASME Operation and Maintenance of Nuclear Power Plants 2012, and the linear cumulative damage due to fatigue can be obtained from the linear cumulative damage rule. To verify the performance of the method, the vibration response of a cantilever pipe is calculated for four earthquake waves, and the cumulative fatigue damage is evaluated using the rain flow method. The result is in good agreement with the value obtained by the method based on the relative response. When the response spectrum obtained by the evaluation method is considered, the value obtained by the evaluation method has a peak at the peak frequency of the ground motion, and the value decreases with increasing natural frequency above the peak frequency. A higher peak frequency of the base leads to a higher value obtained by the evaluation method.

Evaluation Method for Seismic Fatigue Damage of Plant Pipeline

2017 ◽  
Author(s):  
Fumio Inada ◽  
Michiya Sakai ◽  
Ryo Morita ◽  
Ichiro Tamura ◽  
Shin-ichi Matsuura ◽  
...  
Keyword(s):  
Fatigue Damage ◽  
Nuclear Power ◽  
Power Plants ◽  
Evaluation Method ◽  
Response Spectrum ◽  
Damage Mechanism ◽  
Peak Frequency ◽  
Cumulative Damage ◽  
Cumulative Absolute Velocity ◽  
Seismic Index

Although acceleration and cumulative absolute velocity (CAV) are used as seismic indexes, their relationship with the damage mechanism is not yet understood. In this paper, a simplified evaluation method for seismic fatigue damage, which can be used as a seismic index for screening, is derived from the stress amplitude obtained from CAV for one cycle in accordance with the velocity criterion in ASME Operation and Maintenance of Nuclear Power Plants 2012, and the linear cumulative damage due to fatigue can be obtained from the linear cumulative damage rule. To verify the performance of the method, the vibration response of a cantilever pipe is calculated for four earthquake waves, and the cumulative fatigue damage is evaluated using the rain flow method. The result is in good agreement with the value obtained by the method based on the relative response. When the response spectrum obtained by the evaluation method is considered, the value obtained by the evaluation method has a peak at the peak frequency of the ground motion, and the value decreases with increasing natural frequency above the peak frequency. A higher peak frequency of the base leads to a higher value obtained by the evaluation method.

scholarly journals Research on Improved Seismic Instrumentation System for Nuclear Power Plants

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4262
Author(s):  
Liang Li ◽  
Xiuli Du ◽  
Rong Pan ◽  
Xiuyun Zhu ◽  
Haiyan Luan
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Response Spectrum ◽  
Ground Acceleration ◽  
Cumulative Absolute Velocity ◽  
Safety Regulations ◽  
Seismic Instrumentation ◽  
Three Components

According to the requirements of nuclear safety regulations, nuclear power plants must be equipped with seismic instrumentation systems, which are mainly used for monitoring alarm and automatic shutdown alarm during an earthquake. Both the second and third generation NPPs adopt Peak Ground Acceleration (PGA). However, among the seismic acceleration characteristics, isolated and prominent single high frequency acceleration peaks have no decisive influence on the seismic response. Especially when the earthquake monitoring alarm is at 1 out of 7, it is likely to cause a false alarm or false shutdown. In addition, it usually takes one month or more for the NPPs to restart after the shutdown. In this paper, an improved seismic instrumentation system based on the existing system is proposed. For high intensity areas, three components resultant acceleration is used to judge the 2 out of 4 logic of the automatic seismic trip system(ASTS). For low intensity areas, the seismic failure level is evaluated quickly by using three components resultant acceleration, seismic instrument intensity, cumulative absolute velocity, floor response spectrum and other multi-parameters, avoiding unnecessary and long-term shutdown inspection.

INTERCOMPARISON ON INTERNAL DOSE ASSESSMENT FOR NUCLEAR POWER PLANTS IN KOREA

2019 ◽  
Vol 186 (4) ◽  
pp. 524-529
Author(s):  
Si Young Kim
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Evaluation Method ◽  
Dose Assessment ◽  
Assessment Procedure ◽  
Internal Dose ◽  
Nuclear Facilities ◽  
International Intercomparison ◽  
Selection Of

Abstract The intercomparison test is a quality assurance activity performed for internal dose assessment. In Korea, the intercomparison test on internal dose assessment was carried out for nuclear facilities in May 2018. The test involved four nuclear facilities in Korea, and seven exposure scenarios were applied. These scenarios cover the intake of 131I, a uranium mixture, 60Co and tritium under various conditions. This paper only reviews the participant results of three scenarios pertinent to the operation of nuclear power plants and adopts the statistical evaluation method, used in international intercomparison tests, to determine the significance values of the results. Although no outliers were established in the test, improvements in the internal dose assessment procedure were derived. These included the selection of intake time, selection of lung absorption type according to the chemical form and consideration of the contribution of previous intake.

Security Risk Analysis of Nuclear Power Plants Based on Fuzzy Comprehensive Evaluation

2011 ◽  
Vol 130-134 ◽  
pp. 3708-3711
Author(s):  
Chuan Sheng Xie ◽  
Sheng Ping Hua ◽  
Da Peng Dong ◽  
Xiao Xi Jia
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Risk Index ◽  
Fuzzy Comprehensive Evaluation ◽  
Security Risk ◽  
Fuzzy Comprehensive Evaluation Method ◽  
Comprehensive Evaluation Method

A fuzzy comprehensive evaluation method for nuclear power plants is introduced in this article. First, a risk index system is established of which these indicators will be explained accordingly latter. Then, an evaluation set is constructed, and the weight of each index and corresponding membership is determined according to suggestions of experts and membership function to make evaluation level by level ，until a final comprehensive evaluation is obtained. This method is not very objective but simple and available.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 3 — Seismic Response of Crossover Piping for Seismic Isolation System

2014 ◽  
Author(s):  
Akihito Otani ◽  
Teruyoshi Otoyo ◽  
Hideo Hirai ◽  
Hirohide Iiizumi ◽  
Hiroshi Shimizu ◽  
...  
Keyword(s):  
Seismic Response ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Response Spectrum ◽  
Time History ◽  
Response Analysis ◽  
Isolation System ◽  
Isolation Systems ◽  
Seismic Isolation Systems

This paper, which is part of the series entitled “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”, shows the linear seismic response of crossover piping installed in a seismically isolated plant. The crossover piping, supported by both isolated and non-isolated buildings, deforms with large relative displacement between the two buildings and the seismic response of the crossover piping is caused by two different seismic excitations from the buildings. A flexible and robust structure is needed for the high-pressure crossover piping. In this study, shaking tests on a 1/10 scale piping model and FEM analyses were performed to investigate the seismic response of the crossover piping which was excited and deformed by two different seismic motions under isolated and non-isolated conditions. Specifically, as linear response analysis of the crossover piping, modal time-history analysis and response spectrum analysis with multiple excitations were carried out and the applicability of the analyses was confirmed. Moreover, the seismic response of actual crossover piping was estimated and the feasibility was evaluated.

Using Limit Analysis for Seismic Evaluation of Component Located in Nuclear Power Plants

2002 ◽  
Author(s):  
Petr Zeman
Keyword(s):  
Limit Analysis ◽  
Nuclear Power ◽  
Power Plants ◽  
Evaluation Method ◽  
Static Load ◽  
Seismic Load ◽  
Plastic Behavior ◽  
Seismic Evaluation ◽  
Perfectly Plastic ◽  
American Society

Using limit analysis for evaluation of the seismic resistance of the components located in NPPs is compared with the standard evaluation method. This comparison is based on the procedure specified in American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section III. Subsection NC, version 1992 standard. The limit analysis uses perfectly plastic behavior of the material. The seismic load is restricted when using limit analysis to the pseudo-static load. The possibility of building of more realistic non-linear model including contacts is another advantage of limit analysis. Using limit analysis is the way to move the evaluation method closer to the real collapse load and to reduce conservatism.

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