• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.141-147
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• 2017

Mechanical shim is an advanced technology for reactor power and axial offset control with control rod assemblies. To address the adverse accuracy impact on the ex-core power range neutron flux measurements-based axial offset control resulting from the variable positions of control rod assemblies, the lead-lag-compensated in-core self-powered vanadium detector signals are utilized. The prompt ${\gamma}$ current of self-powered detector is ignored normally due to its weakness compared with the delayed ${\beta}$ current, although it promptly reflects the flux change of the core. Based on the features of the prompt ${\gamma}$ current, a method for configuration of the lead-lag dynamic compensator is proposed. The simulations indicate that the method can improve dynamic response significantly with negligible adverse effects on the steady response. The robustness of the design implies that the method is of great value for engineering applications.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1180-1182
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• 2005

In this paper, the design and field analysis of the novel axial flux type permanent magnet(AFPM) motor with double stator and single rotor are investigated. The various design schemes of AFPM based on 3D finite element method are proposed. The effects of slot shapes, various magnetization of PM, and skewing on the cogging torque and average torque have been investigated in detail. From the results, we can improve the cogging torque and average torque characteristics.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.217-218
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• 2015

Two axial flux permanent magnet (AFPM) machines using soft magnetic composite (SMC) and lamination steel are studied. Generally stator cores of AFPM machines are manufactured using SMC because AFPM machines need 3 dimensional core structures. However, SMC cores have very disadvantages in magnetic properties. Especially permeability value is much lower than that of lamination steel, so magnetic field density is also lower. In terms of core losses, SMC cores have much larger loss values than lamination steel cores because SMC core can't be laminated. In this study, AFPM machine was designed using laminated steel, and iron losses in two machines using SMC and laminated steel were studied. Simulations were carried out by a commercial 3-D FEM tool.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.4
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• pp.505-508
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• 2012

A permanent magnet flux switching (PMFS) machine has a simple rotor, whilst both magnets and coils are set in the stator, resulting in easy removal of heat due to both copper loss and eddy current loss in magnets. However, the volume of magnets used in PMFS machines is usually larger than in conventional PM machines, and leakage flux does exist at the non-airgap side. To make full use of the magnets and gain higher power density, a novel 3-dimensional (3D) field PMFS machine is developed. It combines merits of the tubular linear machine, external-rotor rotary machine and axial-flux rotary machine, hence, offers high power density and peak torque capability, as well as efficient utility of magnets owing to the unique configuration of triple airgap fields.

• Journal of Magnetics
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• v.20 no.4
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• pp.360-365
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• 2015

Spatial distributions of magnetic flux density in a newly designed magnetized inductively coupled plasma (M-ICP) etcher were investigated. Radial and axial magnetic flux densities as well as the magnetic flux density on the center of the substrate holder were controllable by placing multiple circular coils around the etcher properly. The plasma density non-uniformity in M-ICP (25 Gauss) can be reduced (1.4%) compared to that in ICP (16.7%) when the neutral gas pressure was 0.67 Pa and a right-hand circularly polarized wave (R-wave) can be propagated in to the etcher by making magnetic flux density increases both radially and axially from the center of the substrate holder.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.676-678
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• 2002

This paper deals with the design and characteristic analysis of a coreless an axial flux permanent magnet (AFPM) motor. Axial-flux permanent magnet motors prove to be the best candidate for application in electric vehicles (EVs) as direct-drive wheel motors, as in comparison with conventional motors they allow design with higher compactness, lightness and efficiency. Recently, issues regarding environment and the diversification of dependence in oil are watched with keen interest. In this theses, through the simulation of AFPM for low and high torque which has stator in the center and two rotors each side, understand its specialty, with this, make a prototype motor and design drive which can enhance the motors stability in low speed. Especially, specialty of motors torque power output will be mainly talked and based on this, possibility of application in EVs will be inspected by the theoretical study and the test.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1075-1076
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• 2011

This paper compares performance characteristics and mechanical design specifications of outer rotor radial flux type and double-sided axial flux type permanent magnet generator for 1.5-kW class small scale wind power applications to suggest most suitable type. In order to analyze electromagnetic performances of two different type generators, this paper performs generating performance and efficiency characteristic analysis from electrical parameters obtained by using nonlinear finite element analysis using commercial software, electromagnetic losses characteristics equations and d-q characteristics equation. Considering the derived electromagnetic performance, mechanical design specifications and manufacturing cost, the best suitable model for 1.5-kW class wind power system is determined, and its experiment was performed to validate the suggested analysis method.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.751-757
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• 2016

The present work discusses two different models of boiling water reactor (BWR) bundle to compare the neutronic characteristics of uranium dioxide ($UO_2$) and uranium zirconium hydride ($UZrH_{1.6}$) fuel. Each bundle consists of four assemblies. The BWR assembly fueled with $UO_2$ contains $8{\times}8$ fuel rods while that fueled with $UZrH_{1.6}$ contains $9{\times}9$ fuel rods. The Monte Carlo N-Particle Transport code, based on the Mont Carlo method, is used to design three dimensional models for BWR fuel bundles at typical operating temperatures and pressure conditions. These models are used to determine the multiplication factor, pin-by-pin power distribution, axial power distribution, thermal neutron flux distribution, and axial thermal neutron flux. The moderator and coolant (water) are permitted to boil within the BWR core forming steam bubbles, so it is important to calculate the reactivity effect of voiding at different values. It is found that the hydride fuel bundle design can be simplified by eliminating water rods and replacing the control blade with control rods. $UZrH_{1.6}$ fuel improves the performance of the BWR in different ways such as increasing the energy extracted per fuel assembly, reducing the uranium ore, and reducing the plutonium accumulated in the BWR through burnup.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.67-67
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• 2001

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.116-116
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• 2002