• Title/Summary/Keyword: In-core detector

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Dynamic rod worth measurement method based on eqilibrium-kinetics status

  • Lee, Eun-Ki;Jo, YuGwon;Lee, Hwan-Soo
    • Nuclear Engineering and Technology
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    • v.54 no.3
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    • pp.781-789
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    • 2022
  • KHNP had licensed Dynamic Control rod Reactivity Measurement (DCRM) method using detector current signals of PWRs in 2006. The method has been applied to all PWRs in Korea for about 15 years successfully. However, the original method was inapplicable to PWRs using low-sensitivity integral fission chamber as ex-core detectors because of their pulse pile-up and the nonlinearity of the mean-square voltage at low power region. Therefore, to overcome this disadvantage, a modified method, DCRM-EK, was developed using kinetics behavior after equilibrium condition where the pulse counts maintain the maximum value before pulse pile-up. Overall measurement, analysis procedure, and related computer codes were changed slightly to reflect the site test condition. The new method was applied to a total of 15 control rods of 1000 MWe and 1400 MWe PWRs in Korea with worths in the range of 200 pcm -1200 pcm. The results show the average difference of -0.4% and the maximum difference of 7.1% compared to the design values. Therefore, the new DCRM-EK will be applied to PWRs using low sensitivity integral fission chambers, and also can replace the original DCRM when the evaluation fails by big noises present in current or voltage signals of uncompensated/compensated ion chambers.

A Comparison of Signal Processing Techniques in Optical Current Sensor for GIS

  • Kim, Young-Min;Park, Jung-Hwan;Jee, Seung-Wook;Lee, Kwang-Sik;Kim, Jung-Bae;Park, Won-Zoo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.9
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    • pp.103-109
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    • 2006
  • This research is contents about output characteristic of optic current sensor that use faraday effect. optic current sensor used in an experiment is consisted of three parts.(1) Source of light used laser diode of 1310[nm].(2) Sensor section manufactured circularly according to gas insulated switchgear. And $9/125[{\mu}m]$ standard single mode optical fiber for communication was installed winding 20 [turn] on sensor section core surroundings of diameter 31 [cm].(3) Electrical signal of PD(Photo detector) is collected using NI company's 16bit DAQ board via terminal block. Collected data analyzed by different three signal processing methods. NI company's $Labview^{TM}$ was used to signal processing software. As a result, In signal processing of optic current sensor, we could know that noise greatly more influences the error generation than fluctuation of light intensity. also, 1 class CT(current transformer) manufacture that have error rate less than 1[%] was available by removing these

Imaging Characteristics of Plastic Scintillating Fiber Screens for Digital Mammography

  • Choi, Won-Young;Walker, James K.;Jing, Zhenxue
    • Journal of Biomedical Engineering Research
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    • v.17 no.2
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    • pp.165-172
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    • 1996
  • A scanning slot digital mammography system Luing a plastic scintillating fiber screen (SFS) is currently being developed To improve the x-ray interaction efficiency and absorption efficiency of an SFS, high Z elements can be added into the scintillating fiber core. In this paper, we investigated theoretically the zero spatial frequency detective quantum efficiency, DQE(0), and modulation transfer function, MTF(f), of three 2 cm thick SFSs made of polystyrene, polystyrene loaded with 5% by weight of lead, and polystyrene Loaded with 10% by weight of tin scintillating fibers. X-ray interaction efficiency, scintillating light intensity distributions and line spread functions were generated using Monte Carlo simulation. DQE(0) and MTF(f) were computed for x-ray energies ranging from 15 to 50 keV. Loading high Z elements into the SFS markedly increased the DQE(0). For x-ray energies used for mammovaphy, DQE(0) values of both high Z element loaded SFSs are about a factor of three higher than the DQE(0) of an Min-R screen. At mammographic x-ray energies, MTF(f) values of all three SFSs are Venter than 50% at 25 Ip/mm spatial frequency, and were found to be dominated by the 20 um individual scintillating fiber diameter used The results show that both hiP DQE(0) and spatial resolution can be achieved with the high Z element loaded SFSs, which make these SFSs attractive for use in a scanning slot detector for digital mammography.

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Verification of High Speed Performance for the Electronic Pedal using a Rotor (회전체를 이용한 전자페달의 고속 성능 검증)

  • KIM, Yong-Kyu;GO, Jun-Young;YOON, Yong-Ki;KIM, Ju-Yeop;LEE, Jong-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.8
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    • pp.1450-1456
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    • 2016
  • In this paper, we have checked a method of performance evaluation for electronic pedal, which is a core technology of HBD for detecting the axle temperature of high-speed train. As it is practically impossible to conduct train speed test of 500 km/h, we utilize a high speed rotor for evaluating high speed performance of the electronic pedal instead. According to this method, we found that the measurement results by the velocity measuring instrument is similar with the ones from this research through the high speed rotor. In conclusion, it will be possible to conduct reliability evaluation for high speed performance for Beacon, Balise and RFID, which are utilized for transmitting vital information of train control systems through using the rotor.

Energy spectrum of particles arriving at the ground and S(800) determination by Monte Carlo simulation for Telescope Array

  • Kim, Ji-Hee;Roh, Soon-Young;Ryu, Dong-Su;Kang, Hye-Sung;Kasahara, Katuaki;Kido, Eiji;Taketa, Akimichi
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.2
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    • pp.58.1-58.1
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    • 2010
  • Telescope Array (TA) experiment in Utah, USA, observes ultrahigh-energy cosmic rays (UHECRs); UHECRs refer cosmic rays with energy above $10^{18}eV$. Using COSMOS and CORSIKA, we have produced a library of over 1000 thinned extensive air shower (EAS) simulations with the primary energies ranging from $10^{18.5}eV$ to $10^{20.25}eV$ and the zenith angle of primary cosmic ray particle from $0^{\circ}$ to $45^{\circ}$. Here, we present the energy spectrum of particles arriving at the ground. We have also calculated the detector response evaluated using GEANT4 simulations. Here, we discuss S(800), i.e. the signal at a distance of 800 m from the shower core, as the primary energy estimator.

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Study of photon beam quality tool at magnetic field change in bending magnet (편향전자석의 자장변화에 따른 광자선 선질평가에 관한 고찰)

  • Kim, Jeong-Ho;Yoo, Se-Jong;Park, Myeong-Cheol;Bae, Seok-Hwan;Kim, Ki-Jin
    • Journal of the Korea Safety Management & Science
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    • v.16 no.4
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    • pp.433-439
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    • 2014
  • Beam quality is changed about magnetic field of bending magnet. Evaluation of beam quality using PDD(Percentage Depth Dose) at 10cm depth at recommendation of AAPM(America Academy of Pain Medicine). However this evaluation shows fragmentary element. Therefore this study is applied to three value, 10cm divided by 5cm depth PDD, 20cm divided by 10cm depth PDD, 30cm divided by 20cm depth PDD, at change the magnetic field. PDD is measured at magnetic field changed ${\pm}1%$, ${\pm}2%$ at 6MV(Mega Voltage), 10MV photon. The plan technique is 3 portal plan using Core-Plan at human pelvic phantom. Conventional and presented methods are compared at maximum and minimum dose. The presented method increased discernment of relieve the unequal distribution and energy area than conventional method. Henceforth, application of presented method will be considered. Development of energy measurement method and detector miniaturization will be needed about continuous study.

A Study on the Effect of Gamma Background in Low Power Startup Physics Tests (저출력 노물리 시험에서의 감마 Background의 영향에 관한 연구)

  • Bae, Chang-Joon;Lee, Ki-Bog
    • Nuclear Engineering and Technology
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    • v.25 no.3
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    • pp.361-370
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    • 1993
  • Low power physics tests should be peformed for the domestic pressurized light water reactors (PWRs) after refueling. The tests are peformed to ensure that operating characteristics of the core are consistent with predictions and that the core can be operated as designed. But in some low power physics tests, slow but steady reactivity increasing phenomena were noticed after step reactivity insertion by the control rod movement. These reactivity increasing phenomena are due to the low flux level and the gamma background because an uncompensated ion chamber (UIC) is used as the ex-core neutron detector. The gamma background may affect the results or the lour power physics tests. The aims or this paper are to analyze the grounds of such phenomena, to simulate a reference bank worth measurement test and to present a resolution quantitatively. In this study, the gamma background level was estimated by numerically solving the point kinetics equations accounting the gamma background effect. The reactivity computer check test was simulated to verify the model. Also, an appropriate neutron flux level was determined by simulating the reference bank worth measurement test. The determined neutron flux level is approximately 0.3 of the nuclear heating flux. This level is about 3 times as high as the current test upper limit specified in the test procedure. Then, the findings from this work were successfully applied to Kori unit 4 cycle 7 and Yonggwang unit 1 cycle 7 physics tests.

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A UTMI-Compatible USB2.0 Transceiver Chip Design (UTMI 표준에 부합하는 USB2.0 송수신기 칩 설계)

  • Nam Jang-Jin;Kim Bong-Jin;Park Hong-June
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.42 no.5 s.335
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    • pp.31-38
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    • 2005
  • The architecture and the implementation details of a UTMI(USB2.0 Transceiver Macrocell Interface) compatible USB2.0 transceiver chip were presented. To confirm the validation of the incoming data in noisy channel environment, a squelch state detector and a current mode Schmitt-trigger circuit were proposed. A current mode output driver to transmit 480Mbps data on the USB cable was designed and an on-die termination(ODT) which is controlled by a replica bias circuit was presented. In the USB system using plesiochronous clocking, to compensate for the frequency difference between a transmitter and a receiver, a synchronizer using clock data recovery circuit and FIFO was designed. The USB cable was modeled as the lossy transmission line model(W model) for circuit simulation by using a network analyzer measurements. The USB2.0 PHY chip was implemented by using 0.25um CMOS process and test results were presented. The core area excluding the IO pads was $0.91{\times}1.82mm^2$. The power consumptions at the supply voltage of 2.5V were 245mW and 150mW for high-speed and full-speed operations, respectively.

Dosimetrical Analysis of Reactor Leakage Gamma-rays by Means of Scintillation Spectrometry

  • Jun, Jae-Shik
    • Nuclear Engineering and Technology
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    • v.5 no.4
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    • pp.291-309
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    • 1973
  • Exposure rates due to leakage gamma-rays from operating reactors TRIGA Mark II and III were measured in a horizontal plane by means of scintillation spectrometry using a 3"$\times$3" cylindrical Nal(T1) detector associated with a 400 channel pulse height analyzer under varied conditions of reactor operation. In determining exposure rate due to the leakage gamma-rays at each point of measurement, Moriuchi's spectrum-exposure rate conversion theory was applied instead of using conventional responce matrix method which necessitates very complicated procedures to convert a spectrum into exposure rate. The results show that a basic pattern of "typical" spectrum of the reactor leakage gamma-rays is neither affected by thermal output of the reactor, nor influenced by overall attenuation in radiation intensity. It was indicated that he attenuation of the leakage gamma-rays in air in terms of exposure rate as a whole follows an exponential law, and the total exposure rate due to the leakage gamma-rays at a certain point is nearly proportional to thermal output of the reactor. The complexity in spectrum measured for a movable core reactor, TRIGA Mark III, was analyzed through spectrum resolution, and proper judgement of the leakage gamma-rays in a complex spectrum was discussed.ctrum was discussed.

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Development of All-in-one Attachment Based Steel Pipe Pile Cutting Robot Prototype (강관말뚝 두부정리 및 절단 부위 핸들링 로봇의 프로토타입 개발)

  • Yeom, Dong Jun;Han, Jae Hyun;Jung, Eui Hyun;Kim, Young Suk
    • Korean Journal of Construction Engineering and Management
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    • v.19 no.6
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    • pp.115-123
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    • 2018
  • The primary objective of this study is to develop an all-in-one based steel pipe pile cutting robot prototype that improves the conventional steel pipe pile head cutting work in safety, quality, and productivity. For this, the following research works are conducted sequentially; 1)literature review and expert survey, 2)selection of core technology using AHP analysis, 3)deduction of detail design, 4)verification of structural stability, 5)development of full-scale prototype. As a result leveling laser and laser detector(94.46), plasma cutter(96.72), rotary grapple(98.45) are selected as a core technologies. As an outcome, it is analyzed that gripper, cylinder pivot bracket and gripper base are structurally stable. Their maximum stresses are shown as 43.0%, 19.4%, 5.3% compared to their yield strength respectively. The development of full-scale prototype in this study will be utilized for the development of the all-in-one attachment based steel pipe pile cutting robot commercialization model.