用過燃料池移除衰變熱之研究

本研究是透過實驗方式分析用過燃料池 (Spent fuel pool, SFP)模型之冷卻能力，由單燃料束實驗結果可求得計算流體力學軟體中多孔性介質所需之係數，並驗證實驗與模擬結果。在被動式移除熱實驗中，幾何形狀變化對於自然對流效果影響較大，如改變模型底部空間，使全池溫度降低，溫度降低幅度最大約為55˚C，而底板孔洞減少，全池溫度增加，溫度升高幅度最大約為70˚C。SFP模型上方安裝灑水噴頭，可加強散熱效果。靠近SFP模型邊緣的區域，被噴灑的量較少，不能忽視這個區域的冷卻散熱；而電熱棒束的中心溫度較高，必須加強灑水散熱，而越靠近模型中心，蒸氣流動速度越快，可移除的熱量較多。由全池溫度超過300˚C之電熱棒數量越少，表示灑水量充足。經由實驗結果，越早開始噴灑冷卻SFP模型，可使平均溫度及最高溫度降低，甚至可降低實際燃料池鋯水反應發生的機率。

關鍵字

用過燃料池模型；被動式移除熱；計算流體力學

並列摘要

The experiment of spent fuel pool has been implemented to analyze the cooling capacity in this research. Experiments for single assembly have been conducted to approximate the flow coefficients for porous medium technique to be employed in computational fluid dynamics (CFD) simulations. In the experiment of passive heat removal, the results show that the effect of heat transfer in natural convection is influenced significantly by difference of geometry. The temperature of electric heating rods is decreased by raising the height of backplane from 30cm to 10cm and the maximum decrease in temperature is approximately 55˚C. On the other hand, the temperature of rods is increased by decreasing the amount of holes in backplane and the maximum increase in temperature is approximately 70 ˚C. The spray nozzles are set up above the model to enhance the heat transfer. At the edging region of the pool model, heating assembly could not be sprayed uniformly. Thus the cooling could not be ignored. In addition, the cooling of spray should be enhanced due to the temperature at the center region of heating assembly is higher than the edging region. Gradually, the up-flow steam increases and removes more heat, which is dependent on the position of model from edging to the center. According to the result of cooling, the number of heating rods, which have the temperature up to 300˚C, is less while the coolant is sufficient. As a conclusion, earlier it sprays, lower the average and maximum temperature in the pool and therefore decreasing the probability of zirconium-water reaction in the real spent fuel pool.

並列關鍵字

SFP ； passive heat transfer ； CFD

參考文獻

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用過燃料池移除衰變熱之研究

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