新一代核能電廠耐震機率式風險評估與餘熱移除系統耐震行為研究

Seismic Probabilistic Risk Assessment of Nuclear Power Plants Using Response-Based Fragility Functions and Seismic Behavior of Residual Heat Removal System

游青青(Ching-Ching Yu)

指導教授 ： 黃尹男

國立臺灣大學/工學院/土木工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.00971

摘要

2011 年，Huang 與Whittaker 等人提出了一套新的地震機率式風險評估(Seismic Probabilistic Risk Assessment, SPRA)方法，此法改進現今習用方法之缺點，具有以下特點：1) 採取以結構反應參數為函數之地震易損性曲線；2)使用非線性動力分析決定元件耐震需求；3)採用統計方法增廣反應歷時分析結果的數量；4)使用蒙地卡羅模擬識別元件失效與否。在Huang 與Whittaker 等人提出之SPRA 方法中，需依據核電廠所在廠址之危害度分析決定出8 個由小至大之地震強度等級，據以進行非線性動力分析。然而8 個強度等級是否足夠或過多，卻未曾進行評估。此外，對於土壤結構互制效應、增廣所造成之不確定性及增廣列數亦未曾討論。
本研究將以Huang 與Whittaker 等人發表之SPRA 新方法，對範例電廠進行地震機率式風險評估，藉此探討此方法程序中之優缺點與改進的可能性。並對案例電廠中之餘熱移除系統進行反力牆反覆載重試驗，了解該系統之耐震行為，試驗及分析結果可用於未來研究，建立該系統以結構反應為參數之易損性曲線。本研究結果顯示：1) 使用蒙地卡羅模擬可大幅降低計算時間；2) 考量結構不確定性所計算之風險值較低；3) 增廣矩陣中識別發生目標事件之平均列數與對數標準差為對數線性關係，可據此決定增廣需求矩陣之列數與計算次數；4) SAP2000 分析軟體對於管線之模擬可靠性高，可用於後續建立易損性曲線。

關鍵字

地震機率式風險評估 ； 蒙地卡羅模擬法 ； 餘熱移除系統

並列摘要

Seismic probabilistic risk assessment (SPRA) has been widely used to compute the frequencies of core damage and release of radiation of a nuclear power plant (NPP). In 2011, Huang, Whittaker, and Luco published a SPRA methodology with the following characteristics different from the widely used Zion method: (a) seismic fragility curves are defined as a function of structural response parameters; (b) nonlinear response-history analysis is used to estimate seismic demands for components of NPPs; (c) generating a large number of simulations through statistical manipulation of a relatively small number of structural analyses; (d) Monte Carlo simulation is used to determine damage states of components.
In the study presented in this paper, the seismic risk of a sample NPP was evaluated using the methodology published by Huang, Whittaker, and Luco, and the pros and cons of the methodology will be discussed. The seismic risk studied herein was defined as the annual frequency of unacceptable performance of a sample accident sequence for the
sample NPP. Variations in the strength of structural and non-structural components,damping and soil properties are directly considered in the numerical models used in response-history analysis. The procedure to determine the minimum number of structural analyses was also presented in this study.
In this study, the seismic performance of a critical piping system in the sample NPP was evaluated numerically and experimentally. The results will be used to establish the
response-based fragility curve for the piping system in the next stage of this study.

並列關鍵字

seismic probabilistic risk assessment ； Monte Carlo Simulation ； residual heat removal piping system

參考文獻

S. Vishnuvardhan, P. Gandhi, G. Raghava, M. Saravanan, DM. Pukazhendhi, Sumit Goyal, Sunil Satpute, Suneel K. Gupta, Vivek Bhasin, and K. K. Vaze. (2011). “Quasi-Cyclic Fracture Studies On Narrow Gap Welded Stainless Steel Straight Pipes.” Transactions, SMiRT 21, New Delhi, India.

Applied Technology Council (ATC). (2012). "Seismic performance assessment of buildings. Volume 1 – Methodology." FEMA P-58 pre-release version, Federal Emergency Management Agency. Washington, D.C.

Apsel, R., and Luco, J. (1987). "Impedance functions for foundations embedded in a layered medium: an integral equation approach." Earthquake engineering & structural Dynamics, 15(2), 213-231.

Baker, J. W., and Cornell, C. A. (2006). "Correlation of response spectral values for multicomponent ground motions." Bulletin of the Seismological Society of America, 96(1), 215-227.

Engineers, A. s. o. c. (2007). Seismic rehabilitation of existing buildings, ASCE Publications.