吳文方臺灣大學:機械工程學研究所鄭宇良Cheng, Yu-LiangYu-LiangCheng2010-06-302018-06-282010-06-302018-06-282008U0001-2907200818120300http://ntur.lib.ntu.edu.tw//handle/246246/187348核能發電具有發電成本低及二氧化碳排放量少等優點，在面臨全球能源危機及溫室效應等問題下，核能電廠延役在國外已成為發展趨勢，而在電廠延役前，進行各組件老化評估為首要任務。本文以再循環管路為老化評估對象，其為核能電廠管路系統中極為重要的組件之一，在電廠長期運轉後，會面臨各種老化問題，進而影響電廠安全。因此，本文將以機率破壞力學軟體PRAISE (Piping Reliability Analysis Including Seismic Events)，及國內核一廠之應力資料，針對再循環管路各焊道因疲勞裂縫成長所導致之洩漏問題，進行失效機率估算。研究結果顯示，各焊道於電廠運轉六十年時之失效機率，大致介於 至 之間，其與電廠運轉四十年之失效機率相較，增加之幅度有限，說明此組件具良好之安全性，可提供電廠延役之老化評估參考。除此之外，本研究以機率破壞力學觀點為根基，利用可靠度相關理論，自行建立一套簡易的老化評估模式，除可進行機率式的分析外，另可以定論式分析流程評估單一裂縫成長之情形。分析結果顯示，若同樣以機率式分析流程進行評估，各焊道於電廠運轉六十年時之失效機率，大致介於 至 之間，與PRAISE軟體所計算之結果大致符合，由於其趨於保守，在無完善的套裝軟體可供進行評估之情形下，此分析流程亦不失為一方便且快速的方法，可提供相關人員參考。Nowadays, we are facing problems of global energy crisis and the greenhouse effect. The advantage of low cost and small amount of discharge of makes life extension of existed nuclear power plants an important research topic. The first task of life extension of a power plant is the aging assessment of its components. And one of the most important components of a nuclear power plant is its piping systems. Therefore, in the present study, the aging assessment of reactor recirculation system of an existed nuclear power plant is assessed. In general, after a long period of operation, piping of a reactor recirculation system faces various aging problems that affect the safety of the plant. In the first half of the study, in consideration of fatigue crack growth, probabilistic fracture mechanics software PRAISE (Piping Reliability Analysis Including Seismic Events) is applied to find failure probabilities of welds of the system based on stress data of a BWR (Boiling Water Reactor) plant. The result shows that failure probabilities of welds range from to , and the difference is not significant when evaluated, respectively, after 40-year and 60-year of operation. It indicates that life extension of the system can be considered. In the second half of the study, a rather simple and convenient aging assessment model for the fatigue crack growth problem of nuclear piping is proposed. Like PRAISE, it is also based on the deterministic fatigue crack growth model and can be used to evaluate failure probabilities of piping welds through a probabilistic analysis. The calculated result indicates that failure probabilities of those studied welds are between and . They are compatible with but more conservative than those obtained by PRAISE. Therefore, if PRAISE is not available, the proposed method can be used for the aging assessment and failure probability estimation of a piping system.誌謝 I文摘要 IIbstract III 錄 IV 目 錄 VI 目 錄 VII號說明 IX一章 緒論 1.1 研究背景與動機 1.2 文獻回顧 2.3 研究目的與方法 4.4 論文架構 5二章 機率破壞力學 6.1 可靠度與機率函數 6.1.1 指數分佈 7.1.2 常態機率分佈 8.1.3 對數常態機率分佈 9.1.4 韋伯機率分佈 10.2 破壞力學 11.3 疲勞裂縫成長 12.4 機率破壞力學 13三章 疲勞破壞機率分析概述 21.1 初始裂縫尺寸分佈 21.1.1 裂縫深度分佈 21.1.2 裂縫尺寸比分佈 21.2 疲勞裂縫成長 22.3 應力狀態考量 23.4 蒙地卡羅模擬 24.5 機率圖法 24.5.1 指數機率圖 25.5.2 常態機率圖 25.5.3 對數常態機率圖 25.5.4 韋伯機率圖 26.6 卡方適合度檢定 26.7 應力-強度干涉理論 27.8 失效準則 27四章 再循環管路疲勞裂縫成長模擬-PRAISE分析 33.1 再循環管路系統 33.2 再循環管路系統之持續應力 34.3 再循環管路疲勞破壞機率分析 35.3.1 程式概述 35.3.2 應力強度因子 35.3.3 分析參數決定 37.3.4 分析結果與討論 38五章 再循環管路疲勞裂縫成長模擬-自行建模分析 52.1 老化評估模式 52.2 失效機率分析 54.3 結果與討論 55六章 結論 70考文獻 72錄A 模擬裂縫深度 之完整數據 761732997 bytesapplication/pdfen-US再循環管路失效機率機率破壞力學recirculation pipingfailure probabilityprobabilistic fracture mechanicsthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/187348/1/ntu-97-R95522519-1.pdf