混凝土護箱和金屬護箱是核能界廣泛採用的兩種乾貯系統，台灣目前的乾式貯存規劃分成兩階段，第一階段使用混凝土護箱並採露天貯存方式，第二階段可能引進金屬護箱並對所有乾貯護箱採室內貯存。因為第二階段乾貯預期會有兩種護箱混合貯存於乾貯廠房的情境，考量混凝土、金屬兩類護箱移熱的機制有相當的差異，混合存放策略值得研析。
國內乾式貯存系統熱傳相關的研究相當多，主要著眼於法規要求的長期貯存、短期裝填操作及假想事故下，燃料及乾貯設備組件的溫度仍可維持在法規的溫度、溫升限值及各類材料的容許溫度之內。這些研究大都受限於計算資源，僅能針對特定的護箱型式來進行分析，並無深入探討兩類以上護箱混合置放的情境。福島事故後業界對於冷與熱的用過核子燃料在用過燃料池之擺放規則，曾做過棋盤式交錯置放、1x4置放、1x8置放對熱傳的影響分析，本論文的特色是延伸此概念，對於兩種護箱型式同時存放於室內，運用空氣自然對流以及熱輻射等被動式冷卻機制移熱，深入研究在不同的置放情境下，對於各類護箱熱移除效能的影響。因為不同護箱的移熱機制有相當大的差異，兩類護箱混合存放於同一廠房，涉及複雜的傳導、對流、輻射熱傳，經由大量繁雜的計算和歸納整理，本論文期許能找出較佳的存放策略，提供未來國內第二階段乾貯設計之參考。
本論文以ANSYS Fluent CFD軟體建構乾貯廠房模型及兩種乾貯護箱模型，並在案例分析之前，先參照兩種乾貯護箱的安全分析報告的資訊，完成分析模型的驗證。案例分析階段則先以廠房模型模擬不同的護箱列置方式：包括棋盤式置放、混凝土護箱靠外置放、金屬護箱靠外置放、分區置放；模擬不同的混凝土護箱/金屬護箱比例：60:60、32:88、16:104；模擬不同的護箱間距：5.8 m、5.0 m、4.2 m。以這些列置方式、護箱比例及護箱間距組合，由廠房模型分析結果歸納整理這些擺放策略最受限的參數組合，再以兩種護箱模型計算各個組件的溫度分布，確認仍在容許溫度之內。
在歸納整理出兩類護箱混合存放對熱傳的影響效應後，本論文進一步延伸分析三種國內可能面臨的室內存放情境：全金屬護箱、INER-HPS 16組+金屬護箱、INER-HPS 16組+混凝土護箱。以這些情境分析，與目前預見的實務需求緊密結合，實際運用本研究歸納分析之成果。

Concrete cask system and metal cask system are two kinds of dry storage systems widely used in the nuclear industry. The current dry storage plan in Taiwan is divided into two stages. The first stage will use concrete cask system with outdoor storage. The second stage may introduce metal cask system with all casks indoor storage. Since the second stage of dry storage is expected to have two types of casks mixed and stored in a building, considering the large differences of the heat transfer mechanism of the two types of casks, the mixed storage strategy is worth studying.
Since the computational resources is expensive and restricted, there is no research on two or more type of dry storage cask mixed indoor storage. This study tries to use the idea from recently discharged spent fuel applying checker board, one by four, one by eight storage strategy in the spent fuel pool, which comes from post-Fukushima research, to conceive various indoor cask storage phenomena and compare the effect on the heat transfer. After this study, we have summarized several useful principles about the optima mixed storage strategy.
In this paper, ANSYS Fluent CFD software is used to construct a dry storage building model and two dry storage cask models. Before case study, this paper completed the verification of the cask Fluent models with the information from the final safety analysis reports of the two cask systems.
For the case study, we use the dry storage building model to simulate the various arrangement of the cask systems: including checkerboard placement, concrete casks placed close to the ventilation inlet, metal casks placed close to the ventilation inlet, and partitioned placement (concrete casks placed by corners); simulate various concrete casks/metal casks ratio: 60:60, 32:88, 16:104; simulate various cask pitches: 5.8 m, 5.0 m, 4.2 m. Based on the results of case study, the most restrictive combination of the assumptions was input into two cask models. The analysis result confirms that all the components of the two casks are still within their allowable temperatures.
We analyze three possible indoor storage phenomena in Taiwan: all metal casks, 16 INER-HPS concrete casks + other metal casks, 16 INER-HPS concrete casks + other concrete casks. In addition to reconfirming the correctness of the opinions of this paper, those studies demonstrate the principles established in this paper can be used in practice.

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