• Title, Summary, Keyword: control rod drive mechanism

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Stable Control-rod Double Hold Method of Control Rod Drive Mechanism (원자로 제어봉구동장치의 안정적 제어봉 이중 유지 방법)

  • Cheon, Jong-Min;Kim, Choon-Kyung;Lee, Jong-Moo;Jung, Soon-Hyun;Kim, Seog-Ju;Kwon, Soon-Man
    • Proceedings of the KIEE Conference
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    • pp.555-558
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    • 2003
  • When a fault relating to the urgent alarm occurs, we must prevent control rods from dropping and make one of two grippers in Control Rod Drive Mechanism (CRDM) grip the drive rod laking a control rod assembly. If a gripper with any problem is ordered to grip the drive rod, the gripper which cannot latch the rod stably will fail to take the rod. On the purpose of escaping this bad case, we order two grippers to hold the drive rod and enhance the reliability of holding control rods. This action is called the double hold. In the middle of the movement of the drive rod, the latching of the drive rod can cause friction between a gripper and the drive rod. This state may give damage to both the gripper and the drive rod. In this paper, we have devised the method which can have two grippers hold the drive rod more stably, without damaging the equipment.

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The Method of safe double holding by detecting movements of Control Rod Drive Mechanism (원자로 제어봉구동장치의 동작 검출을 통한 안전한 이중유지 방법)

  • Cheon, Jong-Min;Kinm, Choon-Kyung;Lee, Jong-Moo;Park, Min-Kook;Kwon, Soon-Man
    • Proceedings of the KIEE Conference
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    • pp.2655-2657
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    • 2005
  • When a fault relating to the urgent alarm occurs, we must prevent control rods from dropping and make one of two grippers in Control Rod Drive Mechanism (CRDM) grip the drive rod taking a control rod assembly. To enhance the reliability of holding control rods, we order two grippers to hold the drive rod. This action is called the double holding. In the middle of the movement of the drive rod, the latching of the drive rod can cause friction between a gripper and the drive rod. This state may give damage to both the gripper and the drive rod. In this paper, we have devised the method which can have two grippers hold the drive rod more stably, without damaging the equipment.

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A Monitoring Method of Movements in Control Rod Drive Mechanism using Wavelet Transform (웨이블릿 변환을 이용한 원자로 제어봉구동장치 동작 감시 방법)

  • Cheon, Jong-Min;Kim, Choon-Kyoung;Park, Min-Kook;Lee, Jong-Moo;Kwon, Soon-Man
    • Proceedings of the KIEE Conference
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    • pp.270-272
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    • 2005
  • In this paper, we proposed a new method detecting actions of some components driven by the coil excitation. Nuclear power reactors are typically controlled by the movement of several neutron-absorbing control rods into or out of the reactor core. For moving control rods, we use an electromagnetic-jack-typed mechanism, which is called Control Rod Drive Mechanism. This mechanism moves control rods by the step composed of sequential actions of components. In case any mechanical problems happen in the mechanism, the orders for the control rod movement from the higher system cannot be performed properly. This abnormal state must be monitored and the sequential actions of the components can be the monitoring target. The actions of components generate some deviations in the profiles of the currents flowing into the coils in the mechanism. We focused on this phenomena and devised a new method of detecting the actions of the components in Control Rod Drive Mechanism by using the wavelet transform for observing the current profile.

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Study on Rod Position Indication System using Permanent Magnets with Shielding Plates for a Control Rod Drive Mechanism

  • Lee, Jae Seon;Cho, Sang Soon;Kim, Jong Wook
    • Journal of Magnetics
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    • v.20 no.4
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    • pp.439-443
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    • 2015
  • A control rod drive mechanism (CRDM) is an electromechanical equipment that provides linear movement for the control rods to control the nuclear reactivity in a nuclear reactor. A rod position indication system (RPIS) detects the control rod's position. To enhance the measurement accuracy of the system, a magnetostrictive type sensor with capability of generating operation limiting signals would be adapted instead of a conventional RPIS for a CRDM. An RPIS was modelled for a numerical analysis with the permanent magnets at the stationary limit positions and magnetic shielding plates with a moving permanent magnet. The performance analysis of the RPIS were conducted, and the results were discussed here.

Development of Power Controller for Control Rod Drive Mechanism in Reactor (원자로 제어봉 구동장치 제어시스템용 전력제어기 개발)

  • Kim, Choon-Kyung;Cheon, Jong-Min;Lee, Jong-Moo;Kwon, Soon-Man
    • Proceedings of the KIEE Conference
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    • pp.575-579
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    • 2003
  • In this paper, we describe a Duplex Power Controller for Control Rod Control System(CRCS). A Duplex Power Controller has the various functions for the reliable operations of Control Rod Drive Mechanism(CRDM). Also we have implemented the diverse functions by utilizing the developed Duplex Power Controller. Due to the developed Duplex Power Controller, we are assured that the commercial operation by this system be made before long.

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A Comparative Reliability Evaluation of Rod Control Mechanisms with Corresponding for Nuclear Power Plants (원전용 제어봉구동장치의 해석적인 신뢰성 비교 평가)

  • Kwon, S.;Ahn, J.B.;Cheon, J.M.;Lee, J.M.;Shin, J.R.
    • Proceedings of the KIEE Conference
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    • pp.2646-2648
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    • 2002
  • This paper deals with a comparative evaluation of the reliability of control rod drive mechanisms including their driving methods for nuclear power plants. Basically there exist two types of electromagnetic-jack-type drive mechanisms in commercial use that are called as Control Rod Drive Mechanism and Control Element Drive Mechanism. Each type has corresponding drive sequence to make the movements of insertion and withdrawal. A state-space model is derived for each model graphically. Then the evaluation of the reliability is carried out on the programming tool called SHARPE. The evaluation does not give any meaningful numerical values for the reliability but just shows a relative degree to each other in view of reliability.

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A Power Control System for the Rod Drive Coil of Control Element Drive Mechanism in Pressurized Water Reactor

  • Hwang, Dong-Hwan;Seong, Se-Jin;Park, Gwang-Seok
    • Nuclear Engineering and Technology
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    • v.31 no.1
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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.

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Study of Design and Verification for Control Rod Control System (제어봉 구동장치 제어기기 설계 및 검증에 관한 연구)

  • Yook, Sim-Kyun;Lee, Sang-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.5
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    • pp.593-602
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    • 2004
  • We have developed a digital control rod control system not only to improve its performance but also to improve its reliability and speed of response so that it can replace the old fashioned analog system. However, a new developed digital control system should be tested to prove the validity by using any prototype or mock-up before application. The reliability prediction and the reliability block diagram analysis methods were adopted to verify the reliability of the developed hardware. For the case of software, especially fur a new developed control algorithm it has been tested to prove performances and validation by using a dynamic simulator and mock-up of control rod drive mechanism altogether. Here we want to present some key factors regarding to the new developed digital system with some verification procedures.

A Prototype Design of the Control Rod Drive Mechanism for Nuclear Power Plants (원전용 제어봉 구동장치 원형 설계)

  • Lee, J.M.;Kweon, S.M.;Pyon, H.S.;Kim, K.H.;Chang, K.C.
    • Proceedings of the KIEE Conference
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    • pp.638-640
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    • 2002
  • This paper introduces the design method of a Control Rod Drive Mechanism that consists of 3 coils -lift, movable gripper and stationary gripper coil. The vertical attraction forces of the lift, movable gripper, and stationary gripper armatures are calculated by FEM, then the dynamics with full load is demonstrated.

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Design of Power Controller for Control Rod Drive Mechanism Control System (제어봉 구동장치 제어시스템용 전력함 설계)

  • Nam, J.H.;Lee, J.M.;Jung, S.H.;Shin, J.R.;Cheon, J.M.;Kim, C.K.;Kim, S.J.;Kweon, S.M.
    • Proceedings of the KIEE Conference
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    • pp.2271-2273
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    • 2003
  • Control Rod Control System(CRCS) is to control nuclear reaction of reactor by moving Control Rod Drive Mechanism(CRDM) with speed and direction signal from Reactor Regulating System(RRS). CRCS is made up of two parts : control cabinet and power cabinet. And this paper presents mainly power cabinet design for system reliability. To increase reliability of power cabinet, controller, power supply and communication line arc doubly designed and supervision and diagnosis function are applied.

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