Finite Element Model to Simulate the Spacer Grid Buckling Characteristics

2020 ◽  
Author(s):  
Youngik Yoo ◽  
Joongjin Kim ◽  
Kyongbo Eom ◽  
Hyeongkoo Kim
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fuel Assembly ◽  
Nuclear Fuel ◽  
Grid Cell ◽  
Element Model ◽  
Spacer Grid ◽  
Static Compression ◽  
Fuel Rod ◽  
Nuclear Fuel Assembly

Abstract The purpose of this study is to develop a finite element model that accurately describes the buckling behavior of a spacer grid. The spacer grid is the most important component of a nuclear fuel assembly and supports the fuel rod with a structurally sufficient buckling strength. Therefore, the development of a reliable spacer grid model is essential to evaluate the mechanical integrity of a nuclear fuel assembly. To achieve this objective, a three-dimensional finite element model was proposed to simulate the buckling characteristics and mechanical behavior of a PWR spacer grid. To simulate the exact mechanical properties of the spacer grid cell, the parameter values required for the model were determined by conducting a fuel rod drag test and spacer grid spring/dimple stiffness test. Finally, a spacer grid static compression test and dynamic impact test were performed according to the gap size of the spacer grid cell, and the model was verified by comparing the test and analysis results. The results obtained using the developed spacer grid finite element model agreed well with the mechanical test results, and it was confirmed that both the buckling characteristics and mechanical behaviors of the model were accurately simulated by the proposed model.

Development and Validation of an LS-DYNA Model for Simulating Vertical Drop Test of a Nuclear Fuel Shipping Package

2010 ◽  
Author(s):  
W. Zhao ◽  
B. Hempy ◽  
J. Liu ◽  
W. Stilwell ◽  
R. Rochow
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fuel Assembly ◽  
Nuclear Fuel ◽  
Element Model ◽  
Design Changes ◽  
Hypothetical Accident ◽  
Accident Conditions ◽  
Simplified Finite Element Model ◽  
Development And Validation

To meet shipping package safety requirements for transporting fresh nuclear fuel assemblies, structural performance of the shipping package under hypothetical accident conditions must be evaluated and demonstrated to have adequate protection to the fuel assembly it transports. To efficiently evaluate design changes in the shipping package, a simplified finite element model for the shipping package and fuel assembly has been developed using LS-DYNA. The paper describes the development and validation of the finite element model, along with a few design analysis examples to illustrate its usefulness.

Study on the Lateral Dynamic Crush Strength of a Spacer Grid Assembly for a LWR Nuclear Fuel Assembly

2010 ◽  
Vol 34 (9) ◽  
pp. 1175-1183 ◽  
Author(s):  
Kee-Nam Song ◽  
Sang-Hoon Lee ◽  
Soo-Bum Lee ◽  
Jae-Jun Lee ◽  
Gyung-Jin Park
Keyword(s):  
Fuel Assembly ◽  
Nuclear Fuel ◽  
Spacer Grid ◽  
Nuclear Fuel Assembly ◽  
Crush Strength

Prediction of the Nuclear Fuel Rod Abrasion in the Probability Sense

2016 ◽  
Vol 821 ◽  
pp. 317-324
Author(s):  
Vladimír Zeman ◽  
Zdeněk Hlaváč
Keyword(s):  
Fuel Assembly ◽  
Nuclear Fuel ◽  
Fretting Wear ◽  
Primary Circuit ◽  
Grid Cells ◽  
Operational Parameters ◽  
Spacer Grid ◽  
Mean Values ◽  
Fuel Rod ◽  
Lower Limits

The paper deals with the upper and lower limits estimation of the friction work and fretting wear in the contact of nuclear fuel rods with fuel assembly (FA) spacer grid cells. The friction work is deciding factor for the prediction of the fuel rod cladding abrasion caused by FA vibration. Design and operational parameters of the FA components are understood as random variables defined by mean values and standard deviations. The gradient and three sigma criterion approach is applied to the calculation of the upper and lower limits of the friction work and fretting wear in particular contact surfaces between the fuel rod cladding and some of spacer grid cells. The fuel assembly vibration is excited by pressure pulsations of the cooling liquid generated by main circulation pumps in the coolant loops of the NPP primary circuit. The method is applied for hexagonal type nuclear fuel assembly in the VVER type reactors.

Impact Analysis of a Full Model Doublet-Type Spacer Grid in the Fuel Assembly of a PWR

2004 ◽  
Author(s):  
K. J. Park ◽  
Y. D. Kwon ◽  
G. J. Park ◽  
K. N. Song ◽  
K. H. Yoon
Keyword(s):  
Finite Element ◽  
Fuel Assembly ◽  
Impact Analysis ◽  
Impact Load ◽  
Element Model ◽  
Full Model ◽  
Spacer Grid ◽  
Element Analysis ◽  
Partial Model ◽  
External Impact

A spacer grid is one of the main structural components in the fuel assembly of a Pressurized Light Water Reactor (PWR). It supports fuel rods and maintains geometry from external impact loads. In ICONE10, a paper was published for impact analysis of a partial model spacer grid. A five by five grid model was established and the analysis results were discussed. At this moment, a full model with a sixteen by sixteen grid is analyzed for impact analysis. This grid has a new doublet-type shape. The finite element model with 16×16 grid cells is established for nonlinear analysis. It is composed of inner straps, outer straps, guide thimbles, etc. The model is considered the aspects of welding and the contacts between the components. The critical impact load that leads to plastic deformation is identified. Nonlinear finite element analysis is carried out by a software system called ABAQUS/EXPLICIT. The results are discussed in the context of the previous results from the partial model and incorporation of the analysis results into the design change is discussed.

Compression Experiment And Failure Analysis of Additive Manufactured Multi-Layer Lattice Sandwich Structure

2021 ◽  
Author(s):  
Jun Yan ◽  
Cuncun Jiang ◽  
Zhirui Fan ◽  
Qi Xu ◽  
Hongze Du ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Failure Mode ◽  
Sandwich Structure ◽  
Sandwich Structures ◽  
Element Model ◽  
Structural Deformation ◽  
Displacement Curve ◽  
Static Compression ◽  
Quasi Static Compression

The rapid development of additive manufacturing technology provides a new opportunity for the fabrication and research of multi-layer lattice sandwich structures, and thereby some excellent performances can be further discovered. Based on the manufacturing-experiment-analysis technical route, the failure mode of the additive manufactured aluminum multi-layer alloy lattice sandwich structure under quasi-static compression is systematically studied in this paper. Through the combination of experimental observation and finite element analysis, the complex failure mechanism of the multi-layer lattice sandwich structure is revealed. The results show that the multi-layer lattice sandwich structure under quasi-static compression conditions mainly manifests as a layer-by-layer failure mode of the internal lattice structure, which includes the yield, plastic buckling and material damage. At the same time, in comparison with the force–displacement curve and the structural deformation in the key locations, the analysis accuracy of the finite element model can be verified by the compression experiment. Based on the verified finite element model, the most significant influence of different face panel thicknesses, as well the rod radiuses and tilting angles on the energy absorption (EA) is identified via sensitivity analysis. Furthermore, size factors on the structural EA are revealed. This study can provide a helpful guidance for the design of multi-layer lattice sandwich structures in practical applications.

Predicting Radionuclide Release Rates from Spent Nuclear Fuel Inside a Failed Waste Disposal Container Using a Finite Element Model

CORROSION ◽  
10.5006/2866 ◽  
2018 ◽  
Vol 75 (3) ◽  
pp. 302-308 ◽  
Author(s):  
Nazhen Liu ◽  
Ziyan Zhu ◽  
Linda Wu ◽  
Zack Qin ◽  
James J. Noël ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Nuclear Fuel ◽  
Waste Disposal ◽  
Spent Nuclear Fuel ◽  
Element Model ◽  
Release Rates ◽  
Radionuclide Release
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