Seismic qualification of equipment including piping is performed by using floor response spectra (FRS) or in-structure response spectra (ISRS) as the earthquake input at the base of the equipment. The amplitude of the FRS may be noticeably reduced when obtained from coupling analysis because of interaction between the primary structure and the equipment. This paper introduces a method using a modal synthesis approach to generate the FRS in a coupled primary-secondary system that can avoid numerical instabilities or inaccuracies. The FRS were generated by considering the dynamic interaction that can occur at the interface between the supporting structure and the equipment. This study performed a numerical example analysis using a typical nuclear structure to investigate the coupling effect when generating the FRS. The study results show that the coupling analysis dominantly reduces the FRS and yields rational results. The modal synthesis approach is very practical to implement because it requires information on only a small number of dynamic characteristics of the primary and the secondary systems such as frequencies, modal participation factors, and mode shape ordinates at the locations where the FRS needs to be generated.

Seismic qualification of instruments and devices mounted on electrical cabinets in a nuclear power plant is performed in this study by means of the in-cabinet response spectrum (ICRS). A simple method and two rigorous methods are proposed in the EPRI NP-7146-SL guidelines for generating the ICRS. The simple method of EPRI can give unrealistic spectra that are excessively conservative in many cases. In the past, the time domain analysis (TDA) methods have been mostly used to analyze a structure. However, the TDA requires the generation of an artificial earthquake input motion compatible to the target response spectrum. The process of generating an artificial earthquake may involve a great deal of uncertainty. In addition, many time history analyses should be performed to increase the accuracy of the results. This study developed a numerical analysis program for generating the ICRS by frequency domain analysis (FDA) method. The developed program was validated by the numerical study. The ICRS calculated by FDA thoroughly matched with those obtained from TDA. This study then confirms that the method it proposes can simply and efficiently generate the ICRS compared to the time domain method.

원자력발전소중 안전과 관련된 구조물은 지진의 가능성에 대비하여 그의 구조적 안전성과 가용성이 검중되어야 한다. 본 논문은 원자력발전소 보호시스댐 캐비넷올 예롤 들어 그에 대한 내진검증 방법올 보였다. 캐비넷의 유한요소모델을 작성하여 통특성올 구하였고 그 모우드값을 입력지진스펙트럼과 비교한 결과 구조물의 1 차모우드가 입력스펙트럼의 야앓와 일치함으로써 셜계변경의 필요성이 대두되었다. 이 peak 값을 피하기 위하여 캐비넷의 구조를 변경하였고 변경된 구조물에 대하여 웅답스텍트럽해석과 시간 이력해석올 수행하여 구조적 건전성과 가용성올 보임으로써 설계변경된 캐비넷의 내진검증을 확인하였 다

Interest and requirement of seismic qualification for nonstructural components are increasing in South Korea after observing nonstructural component failures by Kyungju earthquake on 12, October, 2016. However, amplification of input motion by hight of building are not considered in most of seismic qualification or design for nonstructural components in South Korea. In this study, seismic loads are compared which is applied to seismic qualification or design for structural or nonstructural component. As a result, amplification effect by vertical location in a building for nonstructural component should be considered for efficient seismic qualifications. Also, further studies are needed how to apply those amplification effects to required response spectra.