• Journal of the Ergonomics Society of Korea
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• v.32 no.1
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• pp.1-7
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• 2013

Objective: This study proposes the application of Ecological Interface Design(EID) method that is effective for situation awareness in digitalized environment. Background: While cognitive interface design method such as Information Rich Display(IRD) is simply focused on existing information for user, EID method helps users' resource to be solved to higher ion task such as diagnostic and problem solving. Method: Using EID method based on Work Domain Analysis (WDA), it was analyzed and designed for Steam Generator(SG) Water Level control process in a digitalized Main Control Room of Nuclear Power Plant. Proposed EID example is evaluated through interviews by expert & operator. Results: The result of expert & operator showed that EID display might give an aid for operator's decision. Conclusion: The results can reduce critical accidental damage that occurred due to cognitive load and so critical human error. Application: This study may be impact on situation awareness study for digitalized interface design.

• Corrosion Science and Technology
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• v.7 no.3
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• pp.187-191
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• 2008

Transgranular stress corrosion cracking of nickel base alloys was reported by Copson and Dean in 1965. Study to establish this cracking mechanism needs to be carried out. Laboratory stress corrosion tests were performed for mill annealed(MA) or thermally treated(TT) steam generator tubing materials in a high temperature water containing lead. An electrochemical interaction of lead with the alloying elements of SG tubings was also investigated. Alloy 690 TT showed a transgranular stress corrosion cracking in a 40% NaOH solution with 5000 ppm of lead, while intergranular stress corrosion racking was observed in a 10% NaOH solution with 100 ppm lead. Lead seems to enhance the disruption of passive film and anodic dissolution of alloy 600 and alloy 690. Crack tip blunting at grain boundary carbides plays a role for the transgranular stress corrosion cracking.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.623-628
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• 1998

A new advanced integral reactor of 330 MWt thermal capacity named SMART (System-Integrated Modular Advanced Reactor) is currently under development in Korea Atomic Energy Research Institute (KAERI) for multi-purpose applications. Modular once-through steam generator (SG) and self-pressurizing pressurizer equipped with wet thermal insulator and cooler are essential components of the SMART. The SMART Provides safety systems such as Passive Residual Heat Removal System (PRHRS). In this study, a computer code for performance analysis of the PRHRS is developed by modeling relevant components and systems of the SMART. Using this computer code, a performance analysis of the PRHRS is performed in order to check whether the passive cooling concept using the PRHRS is feasible. The results of the analysis show that PRHRDS of the SMART has excellent passive heat removal characteristics.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.117-118
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• 2013

증기발생기 화학세정 모사 장치를 이용하여 고농도 화학세정(EPRI/SGOG) 용액인 EDTA(20%)가 인위적으로 제작한 결합 시편에 미치는 영향 평가를 수행하였다. 평가 방법은 세정 전 후 표면 산화막 성분, ECT 분석값 비교, 증기발생기 구성 재료 부식률를 이용하였다. 화학세정 전후 부식률은 A508은 $8.023{\mu}m$, Alloy 600(HTMA)은 $0.007{\mu}m$이며 갈바닉 시편의 경우 $63.193{\mu}m$로 모두 부식 허용치 이내이다. 표면 산화막 성분 및 ECT 분석값 역시 변함이 없었다. 이와 같은 결과로 화학세정 용액인 EDTA는 결함 튜브에 미치는 영향이 없는 것으로 판단된다.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.509-512
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• 2008

본 논문에서는 원전 증기발생기세관 진단을 위한 와전류탐상의 전자기 수치해석을 수행하였다. 전자기적 특성을 해석하기 위하여 맥스웰 방정식을 이용하여 지배방정식을 유도하였고, 3차원 전자기 유한요소 프로그램인 OPERA 3D를 이용하여 전자기 수치 해석을 수행하였다. 신호해석을 위해 사용된 프로브의 종류는 배열와전류프로브이며, FBH 결함의 신호를 해석하였다. 결함의 깊이는 세관 두께의 40[%], 60[%] 및 100[%]로 하였다. 시험주파수는 100[kHz], 300[kHz], 400[kHz]를 사용하였고, 각각의 결함 및 시험주파수에 대한 결과를 비교 분석하였다. 본 논문의 결과는 앞으로 배열와전류프로브를 이용하여 원전 증기발생기세관 진단을 할 경우 신호 해석에 도움이 될 것으로 사료된다.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.50-52
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• 2005

In this paper, the analysis of the eddy current testing(ECT) signals under thc Influence of the ferromagnetic support plate was performed in steam generator(SG) tube of nuclear power plant. In order to remove the influence of the ferromagnetic support plate, a multi-frequency ECT was used. The models which was established for the analysis of the signals is calculated using numerical analysis of finite element method. Through the result of numerical analysis, improved signals is acquired considering the influence of the ferromagnetic support plate using mixing of multi-frequency This paper is presented the residual errors and the phase changes for analysis of the defect signals which should be considered when conducting a ECT using multi-frequency.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.18 no.2
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• pp.37-42
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• 2022

An influence analysis on multiple steam generator tube rupture (mSGTR) followed by an unmitigated station blackout is performed to compare the plant responses according to the number of ruptured u-tubes under the assumption of a total of 10 ruptured u-tubes. In all calculation cases, the transient behaviour of major thermal-hydraulic parameters, such as the discharge flow rate through the ruptured u-tubes, reactor header pressure, and void fraction in the fuel channels is found to be overall similar to that of the base case having a single SG with 10 u-tubes ruptured. Additionally, as the conditions of low-flow coolant with high void fraction in the broken loop continued, causing the degradation of decay heat removal, the peak cladding temperature (PCT) would be expected to exceed the limit criteria for ensuring nuclear fuel integrity. However, despite the same total number of ruptured u-tubes, because of the different connection configuration between the SG and pressurizer, a difference is foud in time between the pressurizer low-level signal and reactor header low-pressure signal, affecting the time to trip the reactor and to reach the PCT limit. The present study is expected to provide the technical basis for the accident management strategy for mSGTR transient conditions of CANDU-6 plants.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.159-165
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• 2008

In this paper the signal analysis of eddy current test using transmit-receive(T/R) pancake coil of ECT array probe using electromagnetic finite element method(FEM) is performed. For characteristics analysis, the notch defect is used. The depth of defect is 40[%] of steam generator tube thickness, and inside defect and outside defect are used as simulation examples. The signal analysis is performed according to the variation of receive coil position. The receive coil is positioned $0[^{\circ}]$, $30[^{\circ}]$, $60[^{\circ}]$, $90[^{\circ}]$ of circumferential position of transmit coil. To obtain e electromagnetic characteristics of robes, the governing equation is derived from Maxwell's equations, and the problem is solved using the 3-dimensional finite element method. The signal magnitude of inside defect is bigger than that of outside defect, and the signal difference can be seen according to the variation of position of receive coil. The experimental signal and numerical signal of ASME standard tube show similar results. The results in this paper can be helpful when the ECT signals from ECT array probe are evaluated and analyzed.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.1
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• pp.61-67
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• 2015

Recently, the initiation of outside diameter stress corrosion cracking (ODSCC) at the tube support plate region of domestic steam generators (SG) with Alloy600 HTMA tubes has been increasing. As a result, SGs with Alloy600 HTMA tubes must be replaced early or are scheduled to be replaced prior to their designed lifetime. ODSCC is one of the biggest threats to the integrity of SG tubes. Therefore, the accurate evaluation of tube integrity to determine ODSCC is needed. Eddy current testing (ECT) is conducted periodically, and its results could be input as parameters for evaluating the integrity of SG tubes. The reliability of an ECT inspection system depends on the performance of the inspection technique and abilty of the analyst. The detection probability and ECT sizing error of degradation are considered to be the performance indices of a nondestructive evaluation (NDE) system. This paper introduces an optimized evaluation method for ECT, as well as the sizing error, including the analyst performance. This study was based on the results of a round robin program in which 10 inspection analysts from 5 different companies participated. The analysis of ECT sizing results was performed using a linear regression model relating the true defect size data to the measured ECT size data.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.5
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• pp.665-671
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• 2013

In a Korean Generation IV prototype sodium-cooled fast reactor (SFR), various types of high-temperature heat exchangers such as IHX (intermediate heat exchanger), DHX (decay heat exchanger), AHX (air heat exchanger), FHX (finned-tube sodium-to-air heat exchanger), and SG (steam generator) are to be designed and installed. In this study, the high-temperature design and integrity evaluation of the sodium-to-air heat exchanger AHX in the STELLA-1 (sodium integral effect test loop for safety simulation and assessment) test loop already installed at KAERI (Korea Atomic Energy Research Institute) and FHX in the SEFLA (sodium thermal-hydraulic experiment loop for finned-tube sodium-to-air heat exchanger) test loop to be installed at KAERI have been performed. Evaluations of creep-fatigue damage based on full 3D finite element analyses were conducted for the two heat exchangers according to the high-temperature design codes, and the integrity of the high-temperature design of the two heat exchangers was confirmed.