ASCE 4 requires that a hard stop be built around the seismic isolation system in nuclear power plants. In order to maintain the function of the isolation system, this hard stop is required to have clearance-to-stop, which should be no less than the 90th-percentile displacements for 150% Design Basis Earthquake (DBE) shaking. Huang et al. calculated clearance-to-stop by using a Latin Hypercube Sampling technique, without considering the rocking behavior of the isolated structure. This paper investigates the effects on estimation of clearance-to-stop due to 1) rocking behavior of the isolated structure and 2) sampling technique for considering the uncertainties of isolation system. This paper explains the simplified analysis model to consider the rocking behavior of the isolated structure, and the input earthquakes recorded at Diablo Canyon in the western United States. In order to more accurately approximate the distribution tail of the horizontal displacement in the isolated structure, a modified Latin Hypercube Sampling technique is proposed, and then this technique was applied to consider the uncertainty of the isolation system. Through the use of this technique, it was found that rocking behavior has no significant effect on horizontal displacement (and thus clearance-to-stop) of the isolated structure, and the modified Latin Hypercube Sampling technique more accurately approximates the distribution tail of the horizontal displacement than the existing Latin Hypercube Sampling technique.

1. 서 론
 2. 면진 원전구조물의 단순화 모델
  2.1 전도거동이 발생하는 단순화 모델
  2.2 면진시스템의 역학적 성질
 3. 입력지진파
  3.1 설계기준지진
  3.2 최대-최소 스팩트럼 적합 지진운동
 4. Latin Hypercube 표본법
  4.1 면진시스템의 불확실성
  4.2 지진파의 불확실성
  4.3 기존 LHS 방법의 문제점 및 개선
 5. 해석 결과
  5.1 전도 거동의 효과
  5.2 샘플링 방법의 효과
 6. 결 론
 / 감사의 글 /
 / REFERENCES /

• 한민수(국민대학교 건설시스템공학과) | Han, Min Soo Corresponding author
• 홍기증(국민대학교 건설시스템공학과) | Hong, Kee Jeung
• 조성국(이노스기술) | Cho, Sung Gook