The control rod driving mechanism (CRDM) is one of the important equipments in the nuclear reactor, and its sealing shell is part of the pressure boundary of the nuclear reactor. The sealing shell is a pressure vessel...
The control rod driving mechanism (CRDM) is one of the important equipments in the nuclear reactor, and its sealing shell is part of the pressure boundary of the nuclear reactor. The sealing shell is a pressure vessel made of two different material (austenitic stainless steel and nickel base alloy) cylinders welded by dissimilar metal welds. Product production process, in this dissimilar metal weld ray detection found suspected defects show. In this paper, the mechanism and process of the suspected defects are expounded through experimental verification, and it is proved that the suspected defects do not affect the quality of the weld.
The ASME code allows the designer to circumvent many of the problems arising in design by elastic analysis by performing plastic or limit analysis of the component. Unlike elastic analysis, these analyses take account...
The ASME code allows the designer to circumvent many of the problems arising in design by elastic analysis by performing plastic or limit analysis of the component. Unlike elastic analysis, these analyses take account of the redistribution of stress upon yield. In limit analysis, the calculation of the limit load for finite plate with different semi-elliptical defects is an important stage for mechanical safety evaluation. The elastic compensation technique proposed by Mackenzie can be used to provide the limit load of a structure with a finite element method and aims at producing a suitable stress filed for the lower bound theory. In the present study, it is assumed that the finite plate exists three kinds of semi-elliptical cracks with low aspect ratio a/c (a/c=0.1, 0.5 and 1.0), respectively. The improved elastic compensation technique realized by finite element method is applied in the limit load estimation. At last, the results show that the improved elastic compensation technique can be used to obtain the limit value for the finite plate with different semi-elliptical defects under tensile loading. Moreover, the improved elastic compensation technique can be easily implemented in any finite element method and enables the limit load for any complex structure to be obtained swiftly.
OpenFOAM is a free, open-source software package that can be used for the solutions of computational fluid dynamics and simulation of various fluid flow processes. Nevertheless, OpenFOAM still lacks default settings a...
OpenFOAM is a free, open-source software package that can be used for the solutions of computational fluid dynamics and simulation of various fluid flow processes. Nevertheless, OpenFOAM still lacks default settings and a large number of different numerical schemes and turbulent models should be validated. In this paper, the unsteady flow around a cylinder (Re=3900) is calculated by the large eddy simulation of OpenFOAM. The predictions include the drag and lift coefficient, the pressure distribution around the cylinder, the velocity distribution and Reynolds stress distribution in the wake region, as well as the prediction of the recirculation length and separation angle. Thanks to several simulations, these five subgrid-scale (SGS) models are compared and studied: The Smagorinsky SGS model, wall adaptive local eddy visibility SGS model, dynamic SGS model with Lagrangian averaging, dynamic one equation eddy visibility model, one equation eddy visibility model. The numerical results are verified with the published experimental data.
In view of the higher technical requirements of the third generation PWR for the control rod drive mechanism (CRDM), China's third generation nuclear reactor CRDM hook parts are designed to multi-tooth hook with w...
In view of the higher technical requirements of the third generation PWR for the control rod drive mechanism (CRDM), China's third generation nuclear reactor CRDM hook parts are designed to multi-tooth hook with wear-resistant surfacing. The surfacing welding process is simulated and optimized based on finite element simulation, and reasonable welding process and parameters are determined by simulation results in this *** to the optimized welding process, the parts are trial-produced, and the parts of the hook are subjected to metallographic inspection, hardness test and thermal life test. The results show that the optimized hook parts have high hardness and wear resistance, and meet the requirements of the third generation PWR nuclear power plant.
Gas-liquid two-phase flow widely exists in nuclear industry, where the heat flux is quite high. Accurate predictions of key parameters such as void fraction and gas volume fraction are important to the insurance of re...
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Under ocean conditions, the nuclear power plants have complex movements due to the effects of wind and wave. The thermal-hydraulic characteristics of the nuclear power plants under ocean conditions are influenced by i...
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Flywheel, as a kinetic energy storage and conversion device, has promising applications due to its high efficiency, no pollution and long lifetime. In particular, with a three-layer structure packed with heavy metal a...
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CHF plays an important role in the heat transfer process during the external reactor vessel cooling (IVR-ERVC) which is deemed as a very effective way to release the decay heat after the core melted. In this paper, th...
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In nuclear power plant, the reactor annular downcomer acts as the upstream of the reactor core, and boric distribution inside the downcomer is focused in the ECC situation. The relevant study indicates that the inlet ...
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