- 學位論文
電廠餘熱移除管線系統之數值分析與實驗驗證
Numerical Analysis and Experimental Verification of Residual Heat Removal Piping System in Power Plants
摘要
餘熱移除(Residual Heat Removal, RHR)系統為電廠內重要管線系統之一，該系統除熱交換器與閥件外，主要係由管線(Pipes)所組成。當電廠遇到緊急狀況時，提供爐心緊急冷卻水，確保爐心等機組不受高溫損毀。當餘熱移除管線系統受到地震等極端負載時，必須確保其具有足夠強度以維持其正常運作，這是不可忽視的重要議題。本研究旨在降低電廠事故發生的風險，瞭解餘熱移除管線系統受力行為及其所能承受的最大負載。本文主要分成二部份，第一部份為進行元件和系統試驗，瞭解元件與管線系統之受力行為與失效模式，並藉由美國機械工程師學會(ASME)的設計規範確認管線遭受強震仍符合規範要求；第二部份，則以有限元素法進行力學分析，建構適當的法蘭接頭模型與管線系統模型，更進一步提出法蘭接頭之簡化模型。本研究經比較數值模型與試驗結果，確認所建構之模型有一定的精確性，其中採用法蘭接頭簡化模型可減少原本模型70%以上的運算時間，並可據以快速評估電廠餘熱移除管線系統在受到包括強震在內不同負載下的安全性與可靠度。
並列摘要
The Residual Heat Removal (RHR) piping system is one of the most important systems in a nuclear power plant. It is used to provide emergency cooling water to protect the reactor core from high temperature damage during severe accidents. Its strength has therefore to be guaranteed. In order to reduce the accidental risk of power plants, especially owing to strong earthquakes, it is essential to investigate the mechanics behavior of the RHR piping system. This study is divided into two parts. In the first part, both the component test and system test are carried out to investigate the failure modes and mechanics behavior of the RHR piping system. In addition, to confirm the piping system meets the requirements of ASME design code when it is subjected to large earthquakes. In the second part, finite element method is employed for numerical analysis. The numerical models for both the flange joints and the piping system were established and verified according to the experimental results. Furthermore, a simplified model of the flange joints is proposed in this study. By comparing numerical results with the experimental results, it is concluded that all models proposed in this study predict the experimental results reasonably well. In particular, comparing to the original model of the flange joint, the simplified model effectively reduces 70% of the calculation time.