Field Testing to Validate Models Used in Explaining a Piston Problem in a Large Diesel Engine

1993 ◽  
Vol 115 (4) ◽  
pp. 721-727 ◽  
Author(s):  
M. J. Graddage ◽  
F. J. Czysz ◽  
A. Killinger
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Electric Utility ◽  
Analytical Models ◽  
Recording Equipment ◽  
Element Analysis ◽  
Piston Skirt ◽  
Lubrication Conditions ◽  
Engine Start

Two crankcase explosions occurred within one month in diesel engines that drive large emergency generator sets at a nuclear power plant in Eastern Pennsylvania. As a result, the electric utility conducted an extensive investigation to determine the root cause(s) of the problem. Initial inspections confirmed that the crankcase explosions were the result of pistons and liners becoming overheated. The technical challenge was to establish why the pistons and liners were overheating when other engines of the same type did not appear to have the problem in the same duty. Analytical models of piston motion, engine start, and run thermodynamics, and a finite element analysis of piston distortion during engine start and load transients were developed. Preliminary work with these models predicted a feature of the piston design that could adversely affect lubrication conditions during a rapid start and load transient. Final input data to refine the models were needed and these were obtained from tests carried out on a similar diesel generator operated by a municipality in Iowa. This paper describes the successful accomplishment of the field tests using state-of-the-art instrumentation and recording equipment. It also shows how the modeling and test work identified wear at certain locations on the piston skirt as the origin of distress leading to the crankcase explosions. Unfavorable engine starting and loading conditions as well as less than desirable piston skirt-to-liner lubrication conditions in the engines at the nuclear power plant have been identified as the root causes and corrective action has been initiated.

Frequency Analysis of the Motor Control Centers in a Nuclear Power Plant Using Testing and Simulating Methods

2013 ◽  
Vol 479-480 ◽  
pp. 1045-1050
Author(s):  
Wei Ting Lin ◽  
Yuan Chieh Wu ◽  
Chin Cheng Huang
Keyword(s):  
Motor Control ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Shaking Table Test ◽  
Spectral Response ◽  
Shaking Table ◽  
Element Analysis ◽  
Control Center ◽  
Frequency Curves

This study is aim to evaluate the seismic response of the motor control center cabinet in a nuclear power plant using shaking table test and 3D finite element analysis method. Three typical types of motor control center cabinet were used in this study and frequency curves and spectral response acceleration were used as the indices of the dynamic response. The results indicated that the resonance frequency for X and Y direction is about 12 Hz and 15 Hz, respectively, which is verified by the numerical results. The frequencies curves and spectral response acceleration generated by numerical and experimental method were similar and well fitting. Although the numerical method obtained the conservative results, the model accurately represents the dynamic characteristics of the actual motor control center cabinet for seismic verification.

scholarly journals An Investigation on a Quantitative Tomographic SHM Technique for a Containment Liner Plate in a Nuclear Power Plant with Guided Wave Mode Selection

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2819 ◽  
Author(s):  
Yonghee Lee ◽  
Younho Cho
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Elastic Wave ◽  
Nuclear Power ◽  
Guided Waves ◽  
Mode Selection ◽  
Wave Mode ◽  
Guided Wave ◽  
Element Analysis ◽  
Wave Tomography

The containment liner plate (CLP) in a nuclear power plant is the most critical part of the structure of a power plant, as it prevents the radioactive contamination of the surrounding area. This paper presents feasibility of structural health monitoring (SHM) and an elastic wave tomography method based on ultrasonic guided waves (GW), for evaluating the integrity of CLP. It aims to check the integrity for a dynamic response to a damaged isotropic structure. The proposed SHM technique relies on sensors and, therefore, it can be placed on the structure permanently and can monitor either passively or actively. For applying this method, a suitable guided wave mode tuning is required to verify wave propagation. A finite element analysis (FEA) is performed to figure out the suitable GW mode for a CLP by considering geometric and material condition. Furthermore, elastic wave tomography technique is modified to evaluate the CLP condition and its visualization. A modified reconstruction algorithm for the probabilistic inspection of damage tomography algorithm is used to quantify corrosion defects in the CLP. The location and shape of the wall-thinning defects are successfully obtained by using elastic GW based SHM. Making full use of verified GW mode to Omni-directional transducer, it can be expected to improve utilization of the SHM based evaluation technique for CLP.

Fragility of a Flood Defense Structure Subjected to Multi-Hazard Scenario

2016 ◽  
Author(s):  
Saran Srikanth Bodda ◽  
Harleen Kaur Sandhu ◽  
Abhinav Gupta
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Hurricane Sandy ◽  
Nuclear Plant ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Element Analysis ◽  
Dam Foundation ◽  
Flood Defense

The March 2011 Fukushima Daiichi nuclear power plant disaster has highlighted the significance of maintaining the integrity of flood protection systems in the vicinity of a nuclear power plant. In the US, Oyster Creek nuclear plant was shut down when high storm surge during hurricane Sandy threatened its water intake and circulation systems. A gravity dam located upstream of a power plant can undergo seismic failure or flooding failure leading to flooding at the nuclear plant. In this paper, we present the results from a study on evaluating the fragilities for failure of a concrete gravity dam under both the flooding and the seismic events. Finite element analysis is used for modeling the seismic behavior as well as the seepage through foundation. A time-dependent analysis is considered to account for appropriate nonlinearities. Failure of dam foundation is characterized by rupture, and the failure of dam body is characterized by excessive deformation for the flooding and seismic loads respectively. The study presented in this paper has focused on a concrete gravity dam because of the need of validation of models which exist in prior studies only for concrete gravity dams. However, the concepts are directly applicable to any concrete flood defense structure.

Calculation of B2′ Stress Indices for Elbows Using Finite Element Analysis

2008 ◽  
Author(s):  
K. Venkataramana ◽  
V. Bhasin ◽  
K. K. Vaze ◽  
A. K. Ghosh ◽  
H. S. Kushwaha
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Element Analysis ◽  
Stress Indices ◽  
Linear Dynamic ◽  
Dynamic Analyses ◽  
Plant Components

Nuclear power plant components are designed to withstand reversed dynamic loading like earthquake loading. Such reversed dynamic loads may induce plastic deformation in nuclear power plant components like pipe elbows. Plastic deformation in nuclear power plant components is limited by equation (9) of ASME Boiler &Pressure Vessel Code, Section III, NB-3652. ASME B&PV Code was revised in the year 2000 to accommodate plastic ratcheting as a mode of failure instead of plastic collapse under reversed dynamic load. The modified Code contains B2′ index, which is given as 2/3 rd of B2 index for butt-welded elbows. In the earlier work [1] B2′ indices were determined for several elbows using quasi-static nonlinear finite element analysis. In the present work an attempt is made to determine the ratio B2/B2′ for elbows using plastic nonlinear dynamic finite element analysis. Elbows of different sizes were considered in the present study. For each elbow linear static, linear dynamic, plastic nonlinear static and plastic nonlinear transient dynamic analyses are carried out to determine B2′ index in terms of B2 index. Elastic-perfectly plastic material model is used for the elbows. Collapse loads are obtained under static and dynamic conditions. Load vs. deflection curves are obtained for elbows under linear static and nonlinear quasi-static analyses. Deflection vs. time-curves are obtained from linear dynamic and plastic nonlinear dynamic analyses. The ratio B2/B2′ is computed for elbows of different sizes. The computed stress indices are compared with the Code values.

Application of Direct Cyclic Analysis to the Prediction of Plastic Shakedown of Nuclear Power Plant Components

2008 ◽  
Author(s):  
Michael Martin
Keyword(s):  
Finite Element ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Data Storage ◽  
Nuclear Power ◽  
Direct Methods ◽  
Complex Case ◽  
Element Analysis ◽  
Thermal Transients ◽  
Cyclic Approach

The majority of shakedown prediction methods available, amenable to practical engineering application, are based on Melan’s lower bound theorem and are capable only of predicting elastic shakedown. Structural discontinuities and the severe thermal transients typical of nuclear power plant operating scenarios may lead to local, elastically bounded, alternating plasticity. Consequently, Melan’s theorem is not satisfied, often leading to cycle-by-cycle finite element analysis which for large problems may be impractical. In contrast, direct methods lead to reduced data storage and analysis time. Direct methods capable of predicting alternating plasticity are now available, developed to a level applicable to the complex thermo-mechanical loading experienced in real structures. This paper compares the stress-strain response and solution times obtained from the Fourier based direct cyclic approach formulated within the finite element code Abaqus with the cycle-by-cycle method and a superposition implementation of Melan’s theorem. The approaches are applied to the Bree problem and a more complex case representative of a real plant load scenario. Automated application of the direct cyclic approach has resulted in the rapid generation of interaction diagrams, providing the pressure vessel designer with a tool to assess the shakedown sensitivity of structures to changes in the design domain.

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