• Structural Engineering and Mechanics
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• v.2 no.2
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• pp.157-171
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• 1994

A general approach to the dynamic time-history analysis of the reactor core is presented in this paper as a part of the fuel assembly qualification program. Several detailed core models are set up to reflect the placement of the fuel assemblies within the core shroud. Peak horizontal responses are obtained for each model for the motions induced form earthquake. The dynamic responses such as fuel assembly deflected shapes and spacer grid impact loads are carefully investigated. Also, the sensitivity responses are obtained for the earthquake motions and the fuel assembly non-linear response characteristics are discussed.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.14 no.2
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• pp.11-15
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• 2018

A development plan for seismic capacity verification procedures of nuclear components based on the elastic-plastic strain (EPS) features is explained in this paper. The EPS methodology is more realistic to assess seismic responses of components to extreme seismic events beyond the safe shutdown earthquake (SSE) than current practices with the criteria of stress limits. The EPS based approach to analyze the seismic capacity of components can reduce over-conservatism in the current stress-based criteria and can incorporate the seismic responses of components deformed in plastic behavior by the motion of extreme earthquake.

• Nuclear industry
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• v.15 no.2 s.144
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• pp.42-45
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• 1995

모든 원자력관련시설들은 지진으로부터 공공에 아무런 피해를 주지 않는 안전한 설계를 위하여, 일반구조물인 건물, 교량 등의 설계$\cdot$건설을 위하여 정해져 있는 내진설계법규보다도 훨씬 보수적으로 내진설계를 규정하는 원자력법규에 따라 설계 건설되고 있다. 국내의 원자력법규에 정해진 설계기준지진은 안전정지지진(Safe Shutdown Earthquake, SSE)이라 하며, 국내의 원자력발전소 및 원자력관련시설은 안정정지지진의 지반가속도 크기를 0.2g(g는 중력가속도, 1g= 1,000gal=980cm/$sec^2$)로 정하여 사용되고 있다.

• Computational Structural Engineering
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• v.4 no.1
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• pp.17-19
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• 1991

본 글에서는 ANS(American Nuclear Society)에서 규정하고 있는 Safety Class 구조물 중 격납건물의 내진해석모델에 대해 주로 언급하며, 기타 건물(Non-Nuclear Safety "NNS")은 일반건물과 차이점이 없음으로 언급하지 않는다. U.S. NRC(Nuclear Regulatory Commision)는 참고문헌[1]에 의해 원자력 발전소내 여러건물중 SSE(Safe Shutdown Earthquake)하중에도 견디도록 규정하여 정확한 동력학적 계산이 요구되어지나, 그 이외의 건물들은 대개 등가정적 방법에 의해 해석되어진다. 이 해석방법은 여러 빌딩규정들에서 제안된 것으로 지진에 의한 동적하중을 밑면적 단력 또는 각층에 작용하는 층전단력이라는 등가의 정적하중으로 바꿔 계산되며 이 때 사용되는 해석모델은 건물의 기본진동만을 표시할 수 있는 간단한 것이다.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2396-2406
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• 2021

The Pacific Earthquake Engineering Research (PEER) Center has been developing a performance-based earthquake engineering (PBEE) methodology, which is based on explicit determination of performance, e.g., monetary losses, in a probabilistic manner where uncertainties in earthquake ground motion, structural response, damage estimation, and losses are explicitly considered. To carry out the PEER PBEE procedure for a component of the nuclear power plant (NPP) such as the cable tray system, hazard curve and spectra were defined for two hazard levels of the ground motions, namely, operation basis earthquake, and safe shutdown earthquake. Accordingly, two sets of spectral compatible ground motions were selected for dynamic analysis of the cable tray system. In general, the PBEE analysis of the cable tray in NPP was introduced where the resulting floor motions from the time history analysis (THA) of the NPP structure should be used as the input motion to the cable tray. However, for simplicity, a finite element model of the cable tray was developed for THA under the effect of the selected ground motions. Based on the structural analysis results, fragility curves were generated in terms of specific engineering demand parameters. Loss analysis was performed considering monetary losses corresponding to the predefined damage states. Then, overall losses were evaluated for different damage groups using the PEER PBEE methodology.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.7
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• pp.599-604
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• 2012

In this study, the safety of the driving gear reducer of ESW(essential service water) traveling sea water screen was evaluated through seismic analysis. Mode analysis of gear reducer was performed for reliability of analysis. Seismic analysis was performed in operating basis earthquake(OBE) and safe shutdown earthquake(SSE), which were applied as design condition using floor response spectrum( FRS). The maximum strain of gear reducer under OBE and SSE were 20.4 ${\mu}$ and 33.6 ${\mu}$, respectively. The maximum stresses were 2.42 MPa under OBE condition and 4.36 MPa under SSE condition, which were smaller than the allowable strength of material.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.731-736
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• 2011

In this study, the safety of the driving gear reducer of ESW traveling sea water screen was evaluated through seismic analysis. Mode analysis of gear reducer was performed for reliability of analysis. Seismic analysis was performed in Operating Basis Earthquake(OBE) and Safe Shutdown Earthquake(SSE), which was applied as design condition using Floor Respnse Spectrum(FRS). The maxsimum displacement of gear reducer under OBE and SSE were 0.0137 mm and 0.0241 mm, respectively. The maximum stress of gear reducer under OBE and SSE were 2.42 MPa and 4.36 MPa, respectively.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.462-465
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• 2011

본 논문에서는 유한요소모델을 사용하여 원자력 발전용 해수 여과장치에 대한 동적 내진해석을 수행하였다. 장치의 검증을 위해서 운전기준지진(Operating Basis Earthquake, OBE)과 안전정지지진(Safe Shutdown Earthquake, SSE)이 설계하중으로 작용하였을 때 부재에 미치는 영향을 평가하였다. 해석대상은 유한요소법을 사용하여 수학적 모델링을 완성하였고, 층응답스펙트럼(Floor Response Spectrum, FRS)에 따른 지진하중과 사하중등을 적용하여 해석을 수행하였다. 해석된 해수여과장치의 최대변위는 OBE 조건에서 2.5 mm 이고, SSE 조건에서 최대변위는 4.6 mm 이다. 최대응력은 OBE 조건에서 24 MPa, SSE 조건에서 44 MPa이며, 이 값은 재료의 항복강도의 각각 18%, 27% 수준이다. 이에 따라 지진하중조건에 따른 해수여과장치의 구조적 안전성이 제시되었다.

• Earthquakes and Structures
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• v.8 no.3
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• pp.779-799
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• 2015

The slosh height and the possibility of water spill from rectangular Spent Fuel Storage Bays (SFSB) and Tray Loading Bays (TLB) of Nuclear power plant (NPP) are studied during 0.2 g, Safe Shutdown Earthquake (SSE) level of earthquake. The slosh height obtained through Computational Fluid dynamics (CFD) is compared the values given by TID-7024 (Housner 1963) and American concrete institute (ACI) seismic codes. An equivalent amplitude method is used to compute the slosh height through CFD. Numerically computed slosh height for first mode of vibration is found to be in agreement the codal values. The combined effect in longitudinal and lateral directions are studied separately, and found that the slosh height is increased by 24.3% and 38.9% along length and width directions respectively. There is no liquid spillage under SSE level of earthquake data in SFSB and TLB at convective level and at free surface acceleration data. Since seismic design codes do not have guidelines for combined excitations and effect of higher modes for irregular geometries, this CFD procedure can be opted for any geometries to study effect of higher modes and combined three directional excitations.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.67-74
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• 2001

This paper presents the Safe Shutdown Earthquake(SSE) input motion for the seismic design of the Advanced Power Reactor 1400(APR1400). The Design Ground Response Spectra(DGRS) far the SSE is based on the design spectrum specified in regulatory Guide(RG) 1.60 of U.S. Nuclear Regulatory Commission(US NRC), anchored to a Peak Ground Acceleration(PGA) of 0.3g and enriched in the high frequency range. This SSE seismic input motion is to be applied to the seismic analysis as the free-field seismic motion at the ground surface of both the rock and generic soil sites fur APRI1400. The enrichment for APR1400 seismic input motion is performed considering the current US NRC regulations, the seismic hazard studies performed by the Lawrence Livermore National Laboratory (LINL) and Electric Power Research Institute(EPRI) for the Central and Eastern United States nuclear power plant sites, and the seismic input motions used in the design certifications of the three existing U.S. advanced standard plants. It is represented by a set of DGRS and the accompanying Target Power Spectral Density(PSD) Function in both the horizontal and vertical directions.