The Temperature Field of Dispersion Nuclear Fuel Elements

2011 ◽  
Vol 374-377 ◽  
pp. 1955-1958
Author(s):  
Xin Jiang ◽  
Xiao Hang Liu
Keyword(s):  
Thermal Analysis ◽  
Temperature Field ◽  
Heat Generation ◽  
Volume Fraction ◽  
Volume Element ◽  
Heat Generation Rate ◽  
Dispersion Fuel ◽  
The Matrix ◽  
Fuel Particles ◽  
Fuel Elements

A representative volume element is chosen to act as the research object to analyze the temperature field of the dispersion fuel elements. The thermal analysis is carried out for the thermal behaviors using FEM. The results indicate that with the volume fraction and the heat generation rate of the fuel particles increasing, the temperature and the gradient of the temperature in the matrix and the cladding increases markedly.

Thermal Elastoplastic Behavior of Dispersion Nuclear Fuel Elements

2011 ◽  
Vol 339 ◽  
pp. 353-357
Author(s):  
Xin Jiang ◽  
Xiao Hang Liu
Keyword(s):  
Plastic Strain ◽  
Volume Fraction ◽  
Large Strain ◽  
Equivalent Plastic Strain ◽  
Volume Element ◽  
Elastoplastic Behavior ◽  
Dispersion Fuel ◽  
The Matrix ◽  
Fuel Particles ◽  
Fuel Elements

A representative volume element is chosen to act as the research object to analyze the thermal elastoplastic behavior of the dispersion fuel elements. The large strain elastoplastic analysis is carried out for the mechanicalbehaviors using FEM. The results indicate that with the volume fraction of the fuel particles increasing, the Mises stress and the equivalent plastic strain in the matrix increases, and the first principal stress and the equivalent plastic strain in the cladding increases markedly.

The Thermal Expansion Coefficient of Dispersion Nuclear Fuel Elements

2014 ◽  
Vol 1039 ◽  
pp. 85-90
Author(s):  
Li Nie ◽  
Xiao Gang Wang ◽  
Xin Jiang ◽  
Chang Tao Pang
Keyword(s):  
Thermal Analysis ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Nuclear Fuel ◽  
Expansion Coefficient ◽  
Representative Volume Element ◽  
Theoretical Models ◽  
Volume Element ◽  
Dispersion Fuel ◽  
Fuel Elements

A representative volume element is chosen to act as the research object to analyze the thermal expansion coefficient of the dispersion fuel elements. The thermal analysis is carried out for the thermal behaviors using FEM. The results are compared with several theoretical models.

scholarly journals The Electric Current Effect on Electrochemical Deconsolidation of Spherical Fuel Elements

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Xiaotong Chen ◽  
Zhenming Lu ◽  
Hongsheng Zhao ◽  
Bing Liu ◽  
Junguo Zhu ◽  
...  
Keyword(s):  
Electric Current ◽  
Photoelectron Spectroscopy ◽  
Energy Dispersive Spectrometer ◽  
Graphite Powder ◽  
X Ray ◽  
Graphite Matrix ◽  
Free Particles ◽  
The Matrix ◽  
Fuel Particles ◽  
Fuel Elements

For High-Temperature Gas-Cooled Reactor in China, fuel particles are bonded into spherical fuel elements by a carbonaceous matrix. For the study of fuel failure mechanism from individual fuel particles, an electrochemical deconsolidation apparatus was developed in this study to separate the particles from the carbonaceous matrix by disintegrating the matrix into fine graphite powder. The deconsolidated graphite powder and free particles were characterized by elemental analysis, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and ceramography. The results showed that the morphology, size distribution, and element content of deconsolidated graphite matrix and free particles were notably affected by electric current intensity. The electrochemical deconsolidation mechanism of spherical fuel element was also discussed.

scholarly journals Thermal Analysis of ZPPR High Pu Content Stored Fuel

2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
Charles W. Solbrig ◽  
Chad L. Pope ◽  
Jason P. Andrus
Keyword(s):  
Thermal Analysis ◽  
Low Power ◽  
Computer Simulations ◽  
Heat Generation ◽  
Failure Criterion ◽  
Nuclear Reactor ◽  
Heat Generation Rate ◽  
Fuel Temperature ◽  
Fuel Failure ◽  
And Storage

The Zero Power Physics Reactor (ZPPR) operated from April 18, 1969, until 1990. ZPPR operated at low power for testing nuclear reactor designs. This paper examines the temperature of Pu content ZPPR fuel while it is in storage. Heat is generated in the fuel due to Pu and Am decay and is a concern for possible cladding damage. Damage to the cladding could lead to fuel hydriding and oxidizing. A series of computer simulations were made to determine the range of temperatures potentially occuring in the ZPPR fuel. The maximum calculated fuel temperature is 292°C (558°F). Conservative assumptions in the model intentionally overestimate temperatures. The stored fuel temperatures are dependent on the distribution of fuel in the surrounding storage compartments, the heat generation rate of the fuel, and the orientation of fuel. Direct fuel temperatures could not be measured but storage bin doors, storage sleeve doors, and storage canister temperatures were measured. Comparison of these three temperatures to the calculations indicates that the temperatures calculated with conservative assumptions are, as expected, higher than the actual temperatures. The maximum calculated fuel temperature with the most conservative assumptions is significantly below the fuel failure criterion of 600°C (1,112°F).

scholarly journals A Simplified Calculation Method of Heat Source Model for Induction Heating

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2938 ◽  
Author(s):  
Hongbao Dong ◽  
Yao Zhao ◽  
Hua Yuan ◽  
Xiaocai Hu ◽  
Zhen Yang
Keyword(s):  
Heat Flux ◽  
Temperature Field ◽  
Heat Source ◽  
Heat Generation ◽  
Induction Heating ◽  
Generation Rate ◽  
Heat Generation Rate ◽  
Line Heating ◽  
Computation Efficiency ◽  
Computation Process

Line heating is used in forming the complex curve plates of ships, and this process is becoming integrated into automated tools. Induction heating equipment has become commonly used in automatic line heating. When applying automated equipment, it is necessary to calculate the relationship between the heating parameters and the temperature field. Numerical methods are primarily used to accomplish the calculations for induction heating. This computation process requires repeated iterations to obtain a stable heat generation rate. Once the heat generation rate changes significantly, a recalculation takes place. Due to the relative position of the coil and plate changes during heating, the grid needs to be frequently re-divided during computation, which dramatically increases the total computation time. In this paper, through an analysis of the computation process for induction heating, the root node that restricts the computation efficiency in the conventional electromagnetic-thermal computation process was found. A method that uses a Gaussian function to represent the heat flux was proposed to replace the electromagnetic computation. The heat flux is the input for calculating the temperature field, thus avoiding the calculation of the electromagnetic analysis during induction heating. Besides, an equivalence relationship for multi-coil was proposed in this paper. By comparing the results of the experiment and the numerical method, the proposed heat source model’s effectiveness was verified.

scholarly journals A novel determination of the minimal size of a probabilistic representative volume element for fiber-reinforced composites’ thermal analysis

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2551-2564
Author(s):  
Zecan Tu ◽  
Junkui Mao ◽  
Junjun Mao ◽  
Hua Jiang
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Heat Flux ◽  
Thermal Gradient ◽  
Volume Fraction ◽  
Volume Element ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Minimal Size ◽  
Fiber Reinforced

In order to provide an accurate thermal analysis method of fiber-reinforced composites, a novel model based on a probabilistic representative volume element (RVE) is presented in this paper. Monte Carlo methods, probability analysis and finite element analysis have been applied together. The effective transverse thermal conductivity, heat flux field, and thermal gradient field of typical fiber-reinforced composites are examined. The criteria of RVE have been determined, and the minimal size for thermal analysis is obtained using the main statistics and the cross-entropy theory. At the same time, the fiber-to-matrix ratio of thermal conductivity and volume fraction have been changed to determine the influence on heat transfer inside fiber-reinforced composites. It is shown that different purposes of simulations lead to different minimal RVE sizes. The numerical results indicate that the non-dimensional minimal RVE sizes for calculating the effective thermal conductivity, heat flux, and thermal gradient are 30, 80, and 80, respectively. Compared with the volume fraction, the fiber-to-matrix ratio of the thermal conductivity has a more significant effect on minimal RVE size. When the thermal conductivity ratio increases, the minimal size of the RVE increases at first, then it remains almost unchanged.

Numerical Investigation of the Overall Stiffness of Carbon Nanotube-Based Composite Materials

2011 ◽  
Vol 13 ◽  
pp. 47-59 ◽  
Author(s):  
Seyedmehdi Mavalizadeh ◽  
Moones Rahmandoust ◽  
Andreas Öchsner
Keyword(s):  
Carbon Nanotube ◽  
Young’S Modulus ◽  
Case Studies ◽  
Elastic Properties ◽  
Representative Volume Element ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Volume Element ◽  
Matrix Volume ◽  
The Matrix

In this study, a finite element model of a representative volume element that contains a hollow and filled single-walled Carbon nanotube (SWCNT) in two case studies was generated. It was assumed that the nanocomposites have geometric periodicity with respect to local length scale and the elastic properties can be represented by those of the representative volume element (RVE). Elastic properties in agreement with existing literature values for the Carbon nanotube and the matrix were assigned. Then for the two case studies, the tensile test was simulated to find the effect of the geometry, i.e. the volume fraction of matrix and SWCNT's properties variation, on the effective Young's modulus of the structure. In another approach, by applying perpendicular loading to the tube direction, the effect of matrix volume fraction on the transverse Young's modulus was studied. The investigations showed that for both RVEs with filled SWCNT and hollow SWCNT, the effective Young's modulus of the structure decreases approximately linear as the matrix volume fraction increases. The value of Young's modulus of the RVE with a filled Carbon nanotube was obtained to be higher than the RVE with the hollow Carbon nanotube. In addition, by increasing the tube diameter, the effective Young's modulus of the structure increases and the transverse Young's modulus decreases approximately linear for filled tubes but this parameter remains rather constant in the case of the hollow tube by increasing the matrix volume fraction.

Investigating the elastic behavior of carbon nanocone reinforced nanocomposites

2020 ◽  
Vol 234 (14) ◽  
pp. 2908-2922
Author(s):  
Bhavik A Ardeshana ◽  
Umang B Jani ◽  
Ajay M Patel ◽  
Anand Y Joshi
Keyword(s):  
Young’S Modulus ◽  
Representative Volume Element ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Volume Element ◽  
Elastic Behavior ◽  
Representative Volume ◽  
Simulation Based ◽  
Load Carrying ◽  
The Matrix

This paper deals with the evaluation of the effective mechanical properties of carbon nanocone centered composites using a 3D nanoscale representative volume element based on continuum mechanics. For extracting the effective material constants, the authors have taken the basis of theories of elasticity. The results constituting the effective Young's modulus of the composite and Poisson's ratio for different parameters stated above have been presented and validated with rule of mixtures. It can be clearly visualized from the results that the load-carrying capacities of carbon nanocones in the representative volume elements are quite significant and the same has been demonstrated with subsequent cases. Simulation-based modeling can show a considerable part in the improvement of carbon nanocone-based composites by providing results that help in appreciative of the performance of composites. Moreover, for a volume fraction of the CNC as 2.33% in a cylindrical representative volume element and a 19.2° apex angle of the cone, the stiffness of the composite can increase as many as 4.9 times of the matrix. Similarly for hexagonal and square, the increase is in terms of 4.3 and 3.01 times respectively. Cylindrical representative volume element is the best as it provides the maximum reinforcement in terms of effective Young's modulus of the composite. Carbon nanocone-based composites provide results that help in understanding the elastic behavior of composites.

Formation of Persistent Slip Band in Fatigued Copper Single Crystals

1982 ◽  
Vol 40 ◽  
pp. 470-471
Author(s):  
N. Y. Jin
Keyword(s):  
Volume Fraction ◽  
Fatigue Cracks ◽  
Wall Structure ◽  
Matrix Structure ◽  
Dislocation Dipole ◽  
Slip Bands ◽  
Persistent Slip Bands ◽  
The Matrix ◽  
Hard Shell ◽  
Copper Single Crystals

Localised plastic deformation in Persistent Slip Bands(PSBs) is a characteristic feature of fatigue in many materials. The dislocation structure in the PSBs contains regularly spaced dislocation dipole walls occupying a volume fraction of around 10%. The remainder of the specimen, the inactive "matrix", contains dislocation veins at a volume fraction of 50% or more. Walls and veins are both separated by regions in which the dislocation density is lower by some orders of magnitude. Since the PSBs offer favorable sites for the initiation of fatigue cracks, the formation of the PSB wall structure is of great interest. Winter has proposed that PSBs form as the result of a transformation of the matrix structure to a regular wall structure, and that the instability occurs among the broad dipoles near the center of a vein rather than in the hard shell surounding the vein as argued by Kulmann-Wilsdorf.

Preparation of Electron Transparent Metal-Matrix Composites

1968 ◽  
Vol 26 ◽  
pp. 334-335 ◽  
Author(s):  
M. R. Pinnel ◽  
A. Lawley
Keyword(s):  
Stainless Steel ◽  
Load Transfer ◽  
Volume Fraction ◽  
Steel Wire ◽  
Initial Step ◽  
Interfacial Region ◽  
Matrix Composites ◽  
Specific Test ◽  
The Matrix ◽  
The One

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.

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