核能電廠中的核能一級組件在運轉期間，會受到來自壓力及溫度等各項循環暫態負載，且循環負載的大小及發生次數會影響組件的疲勞使用壽命，組件的疲勞使用壽命一直是設計者關注的議題。雖然在設計組件時已考慮到疲勞使用壽命，但安裝完成且開始運轉後，實際上所受到的循環負荷大小和設計值並不相同。 本研究以核電廠的反應爐水淨化取水管線(Reactor Water Clean Up Outlet Nozzle, RWCU)作為分析對象，考慮不同設計負荷條件組合，採用有限元素分析軟體(ANSYS)進行分析，搭配ASME NB-3200的規範求取組件易損耗處的應力值，並計算出累積使用因子，結果顯示這些易損耗處在此設計負荷下之累積使用因子小於1，皆屬於安全範圍之內。 除此之外，本研究亦探討格林函數在計算熱應力之實用性，結果顯示當結構材料特性為定值時，格林函數計算出的熱應力歷程與FEM的結果相當吻合。 ;The class 1 nuclear components are subjected to transient load like pressure and temperature during operation. The cycle number and magnitude of service load may affect the fatigue life of components and that is an important issue to engineering applications. Although the fatigue life of nuclear components had been evaluated in the design stage, the actual transient loads that components subjected to are not the same as the design transient loads. In this study, the Reactor Water Clean Up (RWCU) outlet nozzle of reactor pressure vessel is evaluated. The critical stress value of this component is calculated under combination of different design load conditions by finite element method. Then according to ASME NB-3200 specification, the cumulative usage factor is calculated. The result shows that the maximum cumulative usage factor of the evaluated critical locations are much less than permissible value, 1. In addition, this study also investigates the practicality of Green’s function in thermal stress calculation. The result shows that when material properties are constant, the thermal stress history is in good agreement with that of the finite element method.
