• Nuclear Engineering and Technology
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• 제54권3호
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• pp.888-895
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• 2022

Lately, ocean nuclear power plants have attracted attention as one of diverse uses of nuclear power plants. Because ocean nuclear power plants are movable or transportable, it is necessary to analyze the thermal hydraulics in a moving frame of reference, and computer codes have been developed to predict thermal hydraulics in large moving systems. The purpose of this study is to incorporate a three dimensional dynamic motion model into the SPACE code (Safety and Performance Analysis CodE) so that the code is able to analyze thermal hydraulics in an ocean nuclear power plant. A rotation system that describes three-dimensional rotations about an arbitrary axis was implemented, and modifications were made to the one-dimensional momentum equations to reflect the rectilinear and rotational acceleration effects. To demonstrate the code's ability to solve a problem utilizing a rotational frame of reference, code calculations were conducted on various conceptual problems in the two-dimensional and three-dimensional pipeline loops. In particular, the code results for the three-dimensional pipeline loop with a tilted rotation axis agreed well with the multi-dimensional CFD results.

• 대한환경공학회지
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• 제34권3호
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• pp.155-161
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• 2012

본 연구에서는 고순도 메탄을 회수하기 위해서 Plug Flow Reactor와 External $CO_2$ Stripper를 결합한 중온 Methane Enhancement System을 개발하였다. 반응조 운전인자로서 알칼리도와 Leachate 순환율(LRR, Leachate Recycle Rate)이 바이오가스의 조성과 생성량 및 TVS 제거효율에 미치는 영향을 규명하였다. 고순도 메탄회수 공정 운전결과 OLR 2 g TVS/L-d, 알칼리도 4 g/L as $CaCO_3$, Leachate 순환율 3 v/v-d일 때 평균 94%의 높은 메탄함량을 나타내 고순도 메탄회수를 위한 최적조건임이 밝혀졌다. 이때 1일 반응조 단위 부피당 0.71부피의 메탄이 생성되었으며, TVS 제거율은 79%로서 Control Reactor의 94% 수준을 달성하였다.

• 대한기계학회논문집A
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• 제37권12호
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• pp.1573-1579
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• 2013

핵연료의 연소성능을 시험하기 위해서는 시험 루프에 설치된 조사리그 내에 냉각수가 순환되도록 설계되어야 한다. 이때, 조사리그 내 냉각수는 $300^{\circ}C$, 15.5 MPa 의 고온 고압으로 순환시키기 때문에 냉각수의 밀봉은 핵연료 조사리그를 제작할 때 가장 중요한 공정 중 하나이다. 특히 15 개의 계장선이 조사리그의 압력경계부위를 통과하게 되는데, 이의 밀봉을 위해 일반적으로 브레이징 공정이 적용된다. 본 연구에서는 조사리그 브레이징용 진공챔버 및 고주파 유도가열기를 포함하는 유도 브레이징 시스템을 개발하고, 다양한 실험을 통해 산화막이 발생하지 않는 공정변수를 검토하였으며, 브레이징 제품의 인장시험, 단면검사, 밀봉성능검사 등을 통해 브레이징 공정의 건전성과 밀봉성능을 검증하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.291-295
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• 2007

FTL(Fuel Test Loop) is a facility that confirms performance of nuclear fuel at a similar irradiation condition with that of nuclear power plant. FTL consists of In-Pile Test Section (IPS) and Out-Pile System (OPS). FTL construction work began on August, 2006 and ended on March, 2007. During Construction, ensuring the worker's safety was the top priority and installation of the FTL without hampering the integrity of the HANARO was the next one. Task Force Team was organized to do a construction systematically and the communication between members of the task force team was done through the CoP(community of Practice) notice board provided by the Institute. The installation works were done successfully overcoming the difficulties such as on the limited space, on the radiation hazard inside the reactor pool, and finally on the shortening of the shut down period of the HANARO. Without a sweet of the workers of the participating company of HEC(Hyundae Engineering Co, Ltd), HDEC(HyunDai Engineering & Construction Co. Ltd), equipment manufacturer, and the task force team, it is not possible to install the FTL facility within the planned shutdown period. The Commissioning of the FTL is on due to check the function and the performance of the equipment and the overall system as well. The FTL shall start operation with high burn up test fuels in early 2008 if the commissioning and licensing progress on schedule.

• 한국압력기기공학회 논문집
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• 제9권1호
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• pp.15-19
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• 2013

The auxiliary feedwater is an important to remove the heat from the reactor core when the main feedwater system is unavailable. In most initiating events in Probabilistic Safety Assessment(PSA), the operaton of this system is required to mitigate the accidents. For one of domestic nuclear power plants, a design change of a turbine-driven auxiliary feedwater pump(TD-AFWP), pipe, and valves in the auxiliary system is implemented due to the aging related deterioration by long time operation. This change includes the replacement of the TD-AFWP, the relocation of some valves for improving the system availability, a new cross-tie line, and the installation of manual valves for maintenance. The design modification affects the PSA because the system is critical to mitigate the accidents. In this paper, the safety effect of the change of the auxiliary feedwater system is assessed with regard to the PSA view point. The results demonstrate that this change can supply the auxiliary feedwater from the TD-AFWP in the accident with the motor-driven auxiliary feedwater pump(MD-AFWP) unavailable due to test or maintenance. In addition, the change of MOV's normal position from "close" to "open" can deliver the water to steam generator in the loss of offsite power(LOOP) event. Therefore, it is confirmed that the design change of the auxiliary feedwater system reduces the total core damage frequency(CDF).

• KIEE International Transactions on Power Engineering
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• 제3A권1호
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• pp.27-34
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• 2003

In this paper, the power conditioner composed of the stand-alone single-phase squirrel cage rotor type self-excited induction generator (SEIG) driven by prime movers such as a wind turbine and a micro gas turbine (MGT) is presented by using the steady-state circuit analysis based on the two nodal admittance approaches using the per-unit frequency in addition to a new state variable defined by the per-unit slip frequency along with its performance evaluations for the stand-alone energy utilizations. The stande-alone single-phase SEIG operating performances in unregulated voltage control loop are then evaluated on line under the conditions of the speed change transients of the prime mover and the stand-alone electrical passive load power variations with the simple theoretical analysis and the efficient computation processing procedures described in the part I of this paper. In addition, a feasuible PI controlled feedback closed-loop voltage regulation scheme of the stande-alone single-phase SEIG is designed on the basis of the static VAR compensate. (SVC) and discussed in experiment for the promising stand-alone power conditioner. The experimental operating performance results are illustrated and give good agreements with the simulation ones. The simulation and experimental results of the stand-alone single-phase SEIG with the simple SVC controller for its stabilized voltage regulation prove the practical effectiveness of the additional SVC control loop scheme including the PI controller with fast response characteristics and steady-sate performance improvements.

• Nuclear Engineering and Technology
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• 제25권2호
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• pp.204-214
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• 1993

본 논문은 원자력발전소의 배관설계에 파단전 누설(leak-before-break : LBB) 개념이 적용됨에 따라 새롭게 해석대상이 된 분기관파단에 의한 노심지지배럴의 쉘응답을 계산한 것이다. 앞으로 직경 10인치 이상의 고에너지 배관에 대해 LBB 개념이 적용될 것으로 예상되는 바, 이 경우 LBB 적용대상에서 제외되는 유일한 1차측 배관인 3인치 가압기 분무관의 파단을 가정하였고 이때 노심 지지배럴에 가해지는 쉘응답을 구하였다. 이들 응답을 직경 10인치 이상인 배관파단시의 응답과 비교한 결과 앞으로 직경 10인치 이상의 배관에 대해 LBB 개념이 적용될 경우 배관파단에 대한 노심지지배럴의 쉘응답은 무시할 수 있음을 보였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.761-765
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• 1995

원자력발전소의 제어봉구동장치는 원자로의 압력경계 안에 설치되고 밀봉되므로 센서의 설치가 곤란하여 기존의 제어기는 개루프 형태의 제어기를 사용하고 있다. 본 논문에서는 기존 타이밍모듈의 문제점을 해결하기 위하여 제어봉구동장치 내부에 센서를 설치하지 않고도 제어봉구동장치의 작동 상황을 감시할 수 있는 방법을 개발하였다. 이 방법을 이용하여 제어봉 낙하방지, 정밀한 위치제어, 코일 수명연장의 특성이 있는 제어봉구동장치 타이밍 제어기를 폐루프 제어계통으로 설계하였다. 폐루프 제어개념에 의하여 개발된 알고리즘은 기존의 문제를 대부분 해결하였으며 계통의 성능 및 신뢰도가 향상되었다. 알고리즘 개발 및 시험 시, 여기서 설계한 실시간 제어봉구동장치 시뮬레이터를 사용하였고 현장에서 취득한 실제의 데이터와 함께 이 시뮬레이터를 이용하여 개발한 모든 알고리즘의 검증시험을 하였다. 검증결과 이 타이밍 제어기는 본래의 기능을 잘 수행하는 것으로 나타났다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.305-309
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• 2007

FTL(Fuel Test Loop) is a facility that confirms performance of nuclear fuel at a similar irradiation condition with that of nuclear power plant. FTL construction work began on August, 2006 and ended on March, 2007. During Construction, ensuring the worker's safety was the top priority and installation of the FTL without hampering the integrity of the HANARO was the next one. The installation works were done successfully overcoming the difficulties such as on the limited space, on the radiation hazard inside the reactor pool, and finally on the shortening of the shut down period of the HANARO. The Commissioning of the FTL is to check the function and the performance of the equipment and the overall system as well. The FTL shall start operation with high burn up test fuels in early 2008 if the commissioning and licensing progress on schedule.

• Nuclear Engineering and Technology
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• 제48권6호
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• pp.1321-1329
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• 2016

To get an insight into the operating characteristics of the passive residual heat removal system of molten salt reactors, a two-phase natural circulation test facility was constructed. The system consists of a boiling loop absorbing the heat from the drain tank, a condensing loop consuming the heat, and a steam drum. A steady-state experiment was carried out, in which the thimble temperature ranged from $450^{\circ}C$ to $700^{\circ}C$ and the system pressure was controlled at levels below 150 kPa. When reaching a steady state, the system was operated under saturated conditions. Some important parameters, including heat power, system resistance, and water level in the steam drum and water tank were investigated. The experimental results showed that the natural circulation system is feasible in removing the decay heat, even though some fluctuations may occur in the operation. The uneven temperature distribution in the water tank may be inevitable because convection occurs on the outside of the condensing tube besides boiling with decreasing the decay power. The instabilities in the natural circulation loop are sensitive to heat flux and system resistance rather than the water level in the steam drum and water tank. RELAP5 code shows reasonable results compared with experimental data.