설계초과 고주파 지진에 대한 원전구조물 내진성능평가 기술 개발
Development of seismic performance evaluation technology of nuclear structures for excessively design high frequency earthquake
최근 규모 5.8 (경주), 5.4(포항) 지진이 발생함에 따라 국내 원자력 발전소의 내진성능평가에 대한 관심이 많아졌다. 특히, 국내 지진이 고진동수 성분이 많음이 밝혀짐에 따라 고진동수 지진에 대한 내진성능평가가 중요시 되고 있다. 따라서 본 연구에서는 원자력발전소 주요 구조 요소인 철근콘크리트 벽체에 대한 해석적/실험적 내진 검증을 수행하고 보강 방안 마련을 목표로 한다 (연구기간: 2017.05 ~ 2022.04, 60개월)
- 원자력 발전소 주요 구조요소 저형 벽체 시험을 통한 극한 성능평가 수행
- 격납건물 설계초과 지진에 대한 진동대 시험 수행
- 해석 및 실험을 통한 고진동수 지진 영향 검증
- 원자력 발전소 건물의 설계초과 지진에 대한 내진성능평가 수행 및 평가절차 수립
- 취약벽체에 대한 내진보강방안 제안 및 검증 시험 수행
In recent years, earthquakes of magnitudes 5.8 (Gyeong-Ju) and 5.4 (Po-Hang) had occurred in Korea. These earthquakes were reported to contain high-frequency contents. Thus, concerns about the safety of nuclear power plants under high-frequency earthquakes have increased. In this study, the reinforced concrete wall which is main structural element is evaluated about high-frequency earthquakes analytically and experimentally. (Research period: May. 2017 ~ April. 2022, 60 Months)
Analytical research(Time history analysis)
- Purpose
- Evaluation structural element under seismic force
- Selection of vulnerable member and location
- Analysis of structural behavior according to frequency contents
- Target
- NPP(APR1400) Supplementary building
- Analysis results
- Differences according to frequency contents of earthquake are low.
- Safe at the design based earthquake (DBE, 0.3g)
- HCLPF (High Confidence of Low Probability of Failure) result is shown as 0.4g.
Experimental research (Dynamic loading test)
- Purpose
- Evaluate structural capacity of reinforced concrete wall under high loading-rate
Maximum capacity according to failure mode
- Results
- The Maximum capacity of all specimen was increased
(Flexural: 10%, Sliding: 6%, Shear: 9%)
- Because the material strength was increased due to high-loading rate.
- Related video
- Flexural failure: https://youtu.be/5XH4q2B0JRs
- Sliding failure: https://youtu.be/nVUTolrqg2k
- Shear failure: https://youtu.be/r-T9JbHbvtY
Experimental research (Shaking table test)
- Purpose
- Evaluate structural capacity of reinforced concrete wall under high-frequency earthquake
Maximum capacity & Damping
- Shaking table was carried out changing natural frequency and aspect ratio under elastic.
- Results
- When the dynamic amplification of structure response was greater than 1.5, the damping ratio was limited to lower values with small scatters.
The mean of damping ratio was 2.4% and minus-one S.D. was 2.1%
- Under seismic loading, the maximum capacity was higher than static analysis results because of high-loading rate.
The test using high-frequency earthquake was high flexural capacity than the other test using normal earthquake.