• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권4호
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• pp.147-153
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• 2003

This paper describes the finite element analysis(FEA) for the design of electromagnet for Control Element Drive Mechanism(CEDM) in System-integrated Modular Advanced Reactor(SMART) and compared with the lifting power characteristics of prototype electromagnet. A thermal analysis was performed for the electromagnet. A model for the thermal analysis of the electromagnet was developed and theoretical bases for the model were established. It is important that the temperature of the electromagnet windings be maintained within the allowable limit of the insulation. since the electromagnet of CEDM is always supplied with current during the reactor operation. So the thermal analysis of the winding insulation which is composed of polyimide and air were performed by finite element method. As a result, it is shown that the characteristics of prototype electromagnet have a good agreement with the results of FEA. The thermal properties obtained here will be used as input for the optimization analysis of the electromagnet.

• 한국소음진동공학회논문집
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• 제20권7호
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• pp.658-664
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• 2010

A control element drive mechanism(CEDM) is a reactor regulating system, which inserts, withdraws or maintains a control rod containing a neutron absorbing material within a reactor core to control the reactivity of the core. The ball-screw type CEDM for the integral reactor has a spring-damper system to reduce the impact force due to the scram of the CEDM. This paper describes the experimental results to obtain the drop and damping characteristics of the CEDM. The drop tests are performed by using a drop test rig and a facility. A drop time and a displacement after an impact are measured using a LVDT. The influences of the rod weight, the drop height and the flow area of hydraulic damper on the drop and damping behavior are also estimated on the basis of test results. The drop time of the control element is within 4.5s to meet the design requirement, and the maximum displacement is measured as 15.6 mm. It is also found that the damping system using a spring-hydraulic damper plays a good damper role in the CEDM.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 봄 학술발표회 논문집
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• pp.147-151
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• 1997

The dynamic characteristics of Control Element Drive Mechanism (CEDM) in Korea standard Nuclear Power Plant was reviewed as a secondary mass in a simplified two degree of freedom system, while the reactor vessel as a primary mass. The design improvement stratege to minimize each displacement amplitude of these primary and secondary masses was proposed. According to this stratege the designs of CEDM components, the shroud and the pressure housing, respectively, were changed using optimization technique.

• Nuclear Engineering and Technology
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• 제31권1호
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• pp.1-8
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• 1999

In this paper, we propose a new type of power control system for the rod drive coil of the CEDM of the PWR NPP in order to supply more reliable DC power The electrical modelling of the controlled rod drive coil was done by referring related documentations. The design of the proposed system is based on this electric81 model satisfying the existing specification. A high power DC-DC converter scheme is adopted utilizing the SMPS technique in the design of the proposed system. In order to show the effectiveness of the proposed system, an experimental system with the capability of 3.2 K Watt was set up for a rod with four cores and some computer simulations and experimentations were carried out. The result shows a very similar tracking performance with that of the existing system to the driving command. As a result of this, the proposed method can be applied to the power control system for the rod drive coil of the CEDM of the PWR NPP.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.1919-1920
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• 2006

This paper deals with the design review of a power converter topologies for CEDMCS (Control Element Drive Mechanism Control System). The CEDMCS provides the control signals and motive power to operate the CEDMS. The CEDM's raise and lower the CEAs (Control Element Assemblies) in the reactor core. The CEAs are constructed with the Boron-10 isotope which has a high microscopic cross section of absorption for thermal neutrons. This characteristic causes the addition of negative reactivity when a CEA is inserted and positive reactivity when it is withdrawn from the reactor core.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2262-2273
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• 2020

Digital twin technology can provide significant value for the prognostics and health management (PHM) of critical plant components by improving insight into system design and operating conditions. Digital twinning of systems can be utilized for anomaly detection, diagnosis and the estimation of the system's remaining useful life in order to optimize operations and maintenance processes in a nuclear plant. In this regard, a conceptual framework for the application of digital twin technology for the prognosis of Control Element Drive Mechanism (CEDM), and a data-driven approach to anomaly detection using coil current profile are presented in this study. Health management of plant components can capitalize on the data and signals that are already recorded as part of the monitored parameters of the plant's instrumentation and control systems. This work is focused on the development of machine learning algorithm and workflow for the analysis of the CEDM using the recorded coil current data. The workflow involves features extraction from the coil-current profile and consequently performing both clustering and classification algorithms. This approach provides an opportunity for health monitoring in support of condition-based predictive maintenance optimization and in the development of the CEDM digital twin model for improved plant safety and availability.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.714-716
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• 2000

In the System-integrated modular advanced reactor(SMART), the motor for Control element drive mechanism(CEDM) requires high density power and simple drive mechanism to reduce volume because of restriction by install-space and must satisfy the reactor operating circumstances with high pressure and temperature. In this paper, we perform the basic design of the two kinds (Variable reluctance type and Hibrid-reluctance type) of the transverse flux motor to develop the prototype motor for the control element drive mechanism of SMART. Analyzed these motors by the FEM in the 2-dimension, we show the characteristics for each of the analysis model.

• 전산구조공학
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• 제10권3호
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• pp.225-231
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• 1997

제어봉 구동장치(CEDM)의 동적거동은 원자로의 동적거동과 연동되어 있어, 두 구조물 간의 상호 동적 특성을 이해한 후 CEDM의 설계 개선 방향을 정립해야 한다. 원자로와 CEDM을 각각 1차 질량 및 2차 질량으로 하는 2 자유도계로 단순화하여 상호 동적 영향을 검토하고, 두 질량의 응답을 모두 감소시키는 최적의 .mu.-f곡선을 제시하였다. 설계 개선은 고유진동수비 f를 가능한 0.93부근으로 수렴시켜야 하며, 질량비 .mu.는 감소시키지 않아야 하고, 제시된 최적의 .mu.-f곡선에 접근시키는 방향으로 해야 함을 제안하였다. 이에 따라 CEDM의 부품들의 설계를 최적화하여 원자로와 CEDM의 변위 응답비를 각각 10.5-19.7%와 6.3-3.4%씩 모두 감소시킬 수 있었다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 춘계학술발표회요약집
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• pp.475.1-475
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• 2001

• 한국압력기기공학회 논문집
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• 제12권1호
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• pp.49-55
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• 2016

This paper analyzed a root cause of abnormality in the temperature and vibration at generator-side bearing of motor generator set (MG Set), which is a power supply system to control element drive mechanism (CEDM) of nuclear power plants (NPPs), and modified the design of roller-type and sealing method to improve the abnormalities. From the inspection of MG Set and analysis of temperature variation during service, it was found that the abnormal temperature transition was basically associated with original design of generator-side bearing, whose roller was axially restrained by inner race, and that the abnormal vibration level was caused by inserting small chips of cage and V-ring, which were generated due to the abnormal temperature transition at roller bearing. Type of bearing and sealing method were modified based on these analyses. The temperature and vibration level measured at roller bearing showed that the modifications clearly improved the operational stability of MG Set.