壓水式反應器在運轉一定期間後，就須執行燃料再裝填工作。以往是藉由核子工程師的專家經驗來完成燃料佈局設計，近幾年因計算機發展迅速，使得由電腦程式來搜尋最佳化燃料佈局變得可能。蟻群演算法為一種群智能演算法，適合用於搜尋離散最佳化問題，本研究即以此演算法的三種衍生方法：Rank-Based Ant System(RAS)、Max-Min Ant System(MMAS)及Ant-Q搜尋壓水式反應器燃料佈局，並以馬鞍山核電廠一號機第17、18、19週期廠家排列佈局驗證結果。
設計燃料佈局時，需考慮到安全及經濟因素，在符合安全的條件下，追求最佳的經濟效益。壓水式反應器燃料佈局主要的安全考量有熱通道因子及緩和劑溫度係數，經濟方面的考量為在不違反安全限值的條件下追求較高的週期長度或以較少的燃料束達到能符合能量需求的燃料佈局。壓水式反應器爐心內呈八分之一對稱，針對此對稱模式，研究分兩階段進行，第一階段進行八分之一區域內的位置調換最佳化，第二階段進行區域間的旋轉調換最佳化。
本研究之自動化程式以C語言編寫，利用三維節點爐心模擬程式SIMULATE-3計算爐心狀態。本研究的成果顯示，以台灣馬鞍山核電廠一號機19週期為驗證目標，RAS、MMAS、Ant-Q皆能搜尋到符合安全限值的燃料佈局，在多次重複搜尋的平均中以MMAS表現較好，Ant-Q與RAS表現差不多。再以馬鞍山核電廠一號機17及18週期驗證也能搜尋出符合限值的燃料佈局，證明此自動化工具可適用於其它週期。最後將18週期其中4根燃料束的濃縮度降低，並搜尋出週期長度能夠達到能量需求目標的燃料佈局，使此工具可運用在節省燃料的佈局設計。本研究並在搜尋中以平行運算以節省搜尋所需時間。

In a pressurized water reactor (PWR), the fuel assemblies must be reloaded after operating a period of time. Loading pattern (LP) was designed by engineer based on experience. Because the computer capability is greatly improved in recent years, it is possible to search loading pattern using some algorithms. Ant Colony System is a metaheuristic method which is efficient to combinatorial optimization problem. In this study, three kinds of algorithms, i.e., Rank-Based System (RAS), Max-Min Ant System (MMAS), Ant-Q was adopted to search loading pattern of PWR. Maanshan nuclear power plant cycle 17,18 and 19 was applied to demonstrate the capability of the algorithms.
Safety and economy must be considered in loading pattern design. The main safety constraints include hot channel factor (FΔH) and moderator temperature coefficient (MTC) and the economic consideration is cycle length and cost of fuel. The LP was mirror symmetry in quarter-core and quarter-core rotational symmetry in the full core. The search procedure contained two steps. The first step was to permute fuel assemblies (FA) in 1/8 region and the second step was to perform rotation configuration of these FAs.
The developed program was coded with C. SIMULATE-3 code was used to calculate core status. In Maanshan Cycle 19 case, most of the loading patterns searched by RAS, MMAS and Ant-Q satisfied the safety limits. Generally speaking, MMAS had better performance. The results of Maanshan Cycle 17, 18 also satisfied safety limits, which showed this tool can be applied to other cycles. In addition, the design whose four FAs were placed by lower enrichment FAs also reached the target cycle length. Also, parallel computing was tested to reduce computation time.

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