- 學位論文
高容量乾式貯存系統之等效熱阻與靈敏度分析以及熱傳改善研究
The Study of Effective Thermal Resistance, Its Sensitivity Analysis, and Heat Transfer Improvements in High-Capacity Dry-Storage System
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摘要
本論文對核能研究所開發之高容量乾式貯存系統(HCDSS，High Capacity Dry Storage System)進行三維、穩態之熱傳分析，首先完成所需材料的熱傳導度之靈敏度分析，以解析的方式分析高容量乾式貯存系統中各主要元件之熱阻值，發現乾式貯存系統於傳送護箱模式下之主要熱阻為燃料組件套筒集成、支撐鋼架、密封鋼筒與傳送護箱間之空氣間縫以及中子屏蔽層部位，於混凝土護箱模式下之主要熱阻為燃料組件套筒集成、支撐鋼架、空氣流道以及混凝土護箱與外加屏蔽間之空氣間縫。此研究可作為乾貯系統熱傳改善與操作人員的參考與判斷。接著使用計算流體力學軟體FLUENT 6.12.0版本進行熱傳改良之設計分析，結果顯示對空氣流道提高其放射率為0.8(原始設計為0.36)可使密封鋼筒內元件最高溫度下降5°C至6°C。且本研究亦對混凝土護箱與外加屏蔽結構間之間縫將其上下蓋開孔與環境相通之改善，以增加其自然對流效應之被動式移熱效果，此設計能使密封鋼筒外部溫度下降9°C以上。將空氣流道增加放射率為0.8，並與增加外加屏蔽被動式移熱效果互相結合後，其結果顯示可提高密封鋼筒內部與法規最高溫度限值5 oC至6oC的餘裕，亦可改善於襯墊與混凝土護箱因增加放射率造成溫度增加的問題，使得與原始設計溫度差異不大。乾貯系統各元件最高溫度的降低，對於發展更高容量的乾貯系統是有幫助的，且當系統發生事故問題時，可延長元件失效前的升溫時間而使可進行處理之作業時間增長。
並列摘要
This thesis investigated three-dimensional steady state thermal analysis of the High Capacity Dry Storage System (HCDSS) developed by INER. As our first step, we looked into the sensitivity analysis of thermal conductivities of various materials used in HCDSS. We determined the effective thermal resistances for main components in the system analytically. During the transfer cask mode (TFR), the major contributors of thermal resistances are from sleeves group, supporter, the air gap between transportable Storage Canister (TSC) and transfer cask, and neutron shield. For vertical concrete cask mode (VCC), the additional thermal resistances are air channel, and air gap between the concrete cask and add-on shield. Based on such studies, CFD code such as FLUENT 6.12.0 was then adopted for design analysis on heat transfer improvements. The increase of air channel emissivity (from 0.36 to 0.8) could effectively reduce the maximum temperature bye 5 to 6°C inside the canister. We have also proposed to extend the air gap between the concrete cask and add-on shield through the lids at the top and the bottom. This design change enhances the passive heat removal in natural convection, and a drop of 9°C is observed for the canister outer wall temperature. It is important to reduce the maximum temperatures in the system in order to ensure the safety of the system and ample time of operation before any material failure takes place.
參考文獻
1. U.S. NRC, “Packaging and Transportation of Radioactive Material,” 10 CFR Part 71, April
January 1997.
3. F. Kreith, “Principles of Heat Transfer”, 2nd Edition, International Textbook Company,
Scranton, PA, 1965.
4. U.S. Nuclear Regulatory Commission, “Cladding Considerations for Transportation and