Stress Analysis for Electric Stop Valve of Nuclear Power Plant Considering Action of Preload and Stem Force

2013 ◽  
Vol 313-314 ◽  
pp. 1210-1213
Author(s):  
Ji Wang ◽  
Jian Hua Zheng
Keyword(s):  
Finite Element ◽  
Power Plant ◽  
Nuclear Power ◽  
Thermal Stresses ◽  
Fluid Pressure ◽  
Element Model ◽  
Stop Valve ◽  
Valve Stem ◽  
Reaction Forces ◽  
The Finite Element Model

The finite element model of electric stop valve with flange bolts preload and valve stem force was established to improve the valve stress calculation method which was based only on action of fluid pressure, thermal stresses and pipe reaction forces. The principle and application of pretension load elements were expounded. By ANSYS, the stresses of this valve with preload and valve stem force were calculated, and the Mises equivalent stresses contour and some values of key position of whole valve were obtained. The results indicate the influence of the stresses on the valve caused by preload of bolt mounted on the flange and valve stem force can not be ignored.

Simulation of Behaviors of a One-Third Scale Containment Model Test

2017 ◽  
Author(s):  
Guopeng Ren ◽  
Rong Pan ◽  
Feng Sun
Keyword(s):  
Finite Element ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Finite Element Model ◽  
Internal Pressure ◽  
Nuclear Power ◽  
Element Model ◽  
Scale Model ◽  
Prestress Losses ◽  
The Finite Element Model

Reactor containment of a nuclear power plant is a structure to ensure the safety of nuclear power plant. It acts as the last barrier to prevent the release of radioactive materials from NPP during accidents. Finite element models were established to simulate a 1/3 scale model of a reactor containment building under leakage test pressure. General finite element software ANSYS were applied. The nonlinear behavior of containment materials, geometric were taken into account in the analysis. The reliability of the finite element model was verified through the comparison of theoretical analysis results with experimental results. In the ANSYS finite element model, the concrete, steel bars and prestress tendons were separated and the prestress tendons were considered by the method of cooling method on the prestress tendon elements. The mechanical properties of the finite element model in the prestress tension process and the absolute internal pressure of 0.52MPa were analyzed. Transient and time dependent losses were taken into account at the same time during the calculation of prestress of tendons, so as to calculate effective prestress at different locations of tendons. Calculation results of prestress losses show that the prestress losses at the hole of equipment hatch are larger than the other areas. The results show that, the deformation of over-all structure of the containment is shrink inward under the action of prestress. And the simulation can achieve the consistent deformation effect between tendons and concrete. The maximum radial displacement of the whole containment structure is located at of 10 ° ∼ 20 °area on the right of the hole of the gate. The effect of expansion deformation of the containment caused by design internal pressure is insufficient to offset the inward shrink effect generated by tendons, and the over-all structure of the concrete containment scale model is mainly under compressive stress. The containment test model is still with a large safety margin under the action of design internal pressure. The largest tensile stress is on the up and down areas of the internal sides of the equipment hatch, dome area close to ring beam, and bottom of perimeter wall close to the base slab. There is possibility of cracking on the concrete in limited local zones. This benchmark can provide a reference for engineering design of containment.

Modal Analysis of Axial Vibration of Long Pipeline Delivering Coal Slime in Power Plant

2015 ◽  
Vol 740 ◽  
pp. 112-115
Author(s):  
Qing Wei Shi ◽  
Ya Yun Liu ◽  
Xing Lu Liu ◽  
Xue Di Hao
Keyword(s):  
Finite Element ◽  
Power Plant ◽  
Modal Analysis ◽  
Element Model ◽  
Vibration Characteristics ◽  
Axial Vibration ◽  
Coal Slime ◽  
Pipeline Vibration ◽  
The Finite Element Model ◽  
Intense Vibration

Aiming at the problem of intense vibration of the long pipeline delivering coal slime in the power plant, the finite element model of pipeline is established and modal analysis is carried out by ANSYS. The natural frequency and vibration characteristics of axial vibration are obtained. The vibration characteristics are studied and different pipe segments that produce bigger vibration very easily in operation are determined. Theoretical guidance about pipeline vibration under the external load for further analysis is provided.

scholarly journals Structural Safety Analysis Based on Seismic Service Conditions for Butterfly Valves in a Nuclear Power Plant

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Sang-Uk Han ◽  
Dae-Gyun Ahn ◽  
Myeong-Gon Lee ◽  
Kwon-Hee Lee ◽  
Seung-Ho Han
Keyword(s):  
Finite Element ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Finite Element Model ◽  
Nuclear Power ◽  
Dynamic Properties ◽  
Element Model ◽  
Structural Safety ◽  
Butterfly Valve ◽  
Design Response Spectrum

The structural integrity of valves that are used to control cooling waters in the primary coolant loop that prevents boiling within the reactor in a nuclear power plant must be capable of withstanding earthquakes or other dangerous situations. In this study, numerical analyses using a finite element method, that is, static and dynamic analyses according to the rigid or flexible characteristics of the dynamic properties of a 200A butterfly valve, were performed according to the KEPIC MFA. An experimental vibration test was also carried out in order to verify the results from the modal analysis, in which a validated finite element model was obtained via a model-updating method that considers changes in thein situexperimental data. By using a validated finite element model, the equivalent static load under SSE conditions stipulated by the KEPIC MFA gave a stress of 135 MPa that occurred at the connections of the stem and body. A larger stress of 183 MPa was induced when we used a CQC method with a design response spectrum that uses 2% damping ratio. These values were lower than the allowable strength of the materials used for manufacturing the butterfly valve, and, therefore, its structural safety met the KEPIC MFA requirements.

Finite Element Analysis of Air Cooler Used in Nuclear Power Station

2011 ◽  
Vol 194-196 ◽  
pp. 1982-1985
Author(s):  
Shao Qing Hu ◽  
Yong Li Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Nuclear Power ◽  
Element Model ◽  
Load Case ◽  
Power Station ◽  
Element Analysis ◽  
Operating Load ◽  
Air Cooler ◽  
The Finite Element Model

According to the characteristics of cooler, the finite element model of air cooler is established using ANSYS f software. The force and moment are acted on nozzles using MPC184 element. The first natural frequency is given. Then the stresses of cooler under normal operating load case and under accidental load case are calculated respectively. The stresses of nozzles and foot were checked according to RCC-M specification and meet the requirements.

scholarly journals Dynamic behaviour of nuclear island structure of AP1000 under El Centro and Dien Bien earthquakes

2021 ◽  
Vol 7 (4) ◽  
pp. 34-41
Author(s):  
Lam Dong Vu Lam ◽  
Ngoc Dong Pham ◽  
Dinh Kien Nguyen ◽  
Dai Minh Nguyen ◽  
Tien Thinh Do
Keyword(s):  
Finite Element ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Dynamic Response ◽  
Dynamic Behavior ◽  
Nuclear Power ◽  
Seismic Analysis ◽  
Element Model ◽  
Island Structure ◽  
Finite Element Software

AP1000 is a nuclear power plant developed by Westinghouse based on an advanced passive safety feature, and it is one of selected technologies for Ninh Thuan 2 Nuclear Power Plant. The dynamic behavior of the plant under earthquakes is the most concerned in design and construction of the plant. This paper presents a seismic analysis of the AP1000 nuclear island structure by using the computational finite element software ANSYS. A 3D finite element model for the structure is developed and its dynamic response, including the time histories for displacements, velocities andaccelerations, deformed configurations and von Mises stresses of the structure are obtained for America El Centro (6.9 Richter) and Vietnam Dien Bien (5.3 Richter) earthquakes. A comparison on the dynamic response of the structure under the two earthquakes is given, and the dynamic behavior of the structure under the earthquakes is discussed.

Design Curves for Maximum Stresses in Blocks Containing Pressurized Bore Intersections

1991 ◽  
Vol 113 (4) ◽  
pp. 427-431 ◽  
Author(s):  
J. R. Sorem ◽  
J. R. Shadley ◽  
S. M. Tipton
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Approximation Method ◽  
Fluid Pressure ◽  
Element Model ◽  
Industrial Applications ◽  
Sound Design ◽  
The Finite Element Model ◽  
Maximum Stresses ◽  
Block Dimensions

Intersecting bore geometries are used in a number of industrial applications such as in fluid ends of reciprocating pumps. Maximum tensile stresses at stress concentration points in the block can be many times the fluid pressure in the bores. Obtaining good estimates of the maximum stresses in the structure is necessary for making sound design decisions on the block dimensions. Finite element models of the bore intersection geometry were analyzed for ranges of bore sizes and block dimensions. Results of the finite element model were compared with predictions provided by a popular approximation method based on mechanics of materials principles. The approximation method was found to underpredict the maximum stresses in the block in almost every case analyzed. For some conditions, the maximum stresses computed from the finite element model were more than two times the predictions provided by the approximation method. Design curves, based on the ratio of the sizes of the intersecting bores, are presented for selecting block dimensions to meet desired maximum stress criteria.

Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

2020 ◽  
Vol 38 (1A) ◽  
pp. 25-32
Author(s):  
Waleed Kh. Jawad ◽  
Ali T. Ikal
Keyword(s):  
Finite Element ◽  
Effective Strain ◽  
Element Model ◽  
Cylindrical Shape ◽  
Element Analysis ◽  
Punch Force ◽  
Maximum Value ◽  
Element Simulation ◽  
Blank Sheet ◽  
The Finite Element Model

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

Analysis of Hydroelectric Unit’s Upper Bracket Based on Test and FEM

2014 ◽  
Vol 721 ◽  
pp. 131-134
Author(s):  
Mi Mi Xia ◽  
Yong Gang Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
The Finite Element Method ◽  
Ansys Software ◽  
Element Analysis ◽  
Hydroelectric Unit ◽  
The Finite Element Analysis ◽  
Strain Rosette ◽  
The Finite Element Model

To research the load upper bracket of Francis hydroelectric unit, then established the finite-element model, and analyzed the structure stress of 7 operating condition points with the ANSYS software. By the strain rosette test, acquired the data of stress-strain in the area of stress concentration of the upper bracket. The inaccuracy was considered below 5% by analyzing the contradistinction between the finite-element analysis and the test, and match the engineering precision and the test was reliable. The finite-element method could be used to judge the stress of the upper bracket, and it could provide reference for the Structural optimization and improvement too.

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