福島核電廠事故後核能產業對於燃料池在極端事故下的安全有深刻之疑慮；本研究以CFD進行用過燃料池喪失冷卻後之水位與溫度預測，並假設停機7天後燃料全爐退出之情況下發生喪失冷卻事故，在建立之模式中並未有任何冷卻能力加入，目的為使背景能夠類似於福島事故中之四號機燃料池狀況。目前臺灣運轉中之核電廠包含沸水式以及壓水式兩種機型，採用之燃料與燃料池設計皆不同，因此本研究選擇國聖與馬鞍山兩座電廠為例展開安全分析。本研究將燃料池事故拆分為三階段並分別建立模式：燃料池升溫至飽和溫度、燃料池沸騰水位下降，以及燃料裸露後之升溫。其中CFD僅針對單相之情形做分析，因此第二階段之流程將採用能量守恆估算之方式替代。研究過程中針對國聖電廠用過燃料池分析了設定格架與否、燃料池熱散失之差異，馬鞍山電廠則分析不同格架設計對計算結果之影響。整體燃料事故中燃料只要能夠被水所覆蓋，就能夠保證不會熔毀導致更嚴重後果，而且臺灣電力公司採用NEI 06-12 之建議[1]：用過燃料池喪失正常補水能力後，電廠需具備能於2小時內建立其外部補水的能力，所以在本研究背景條件以及功率設定下之計算結果，顯示台電公司在遭遇較極端的燃料池喪失冷卻事故時，仍足以應付相關用過燃料池的安全保障需求。

The nuclear industry raises doubts about the safety of spent fuel pools in extreme events after the Fukushima Daiichi nuclear disaster. In this research,the prediction of water level and temperature under LOCA(loss of cooling accident) are simulated by using CFD code.Assuming that LOCA occurs after 7 days of post-shutdown with full core unload in spent fuel pool.For the purpose of making the background similar to the Fukushima unit 4 spent fuel pool issues, the model is established without any cooling ability.The nuclear power plant currently in operation including boiling water reactor and pressurized water reactor.Therefore,by choosing the Kuosheng and Maanshan power plants to cover all types of nuclear power plants.The entire accident model is established with three phases separately：The first phase is the water reaches saturation temperature with transient,the second phase is the water level decrease due to boiling and the third phase is the rate of temperture increases rapidly as the spent fuel uncovers with steady state.The second phase of the process will be replaced by energy conservation estimates where CFD is only caculated for single-phase situations in this research.Set the fuel rack or not, various heat loss and the impact of different rack design will be considered in the first phase.As long as the fuel can be covered by water during the accident,it will be able to ensure that meltdown will not happent and lead to more serious consequences.Taipower Company adopted the NEI 06-12 : The system should be capable of being deployed external SFP makeup from the time loss of cooling ability within 2 hours.Therefore, the calculation results under the decay heat settings and background conditions in this research fully proved that Taiwan Power Company is still able to cope with the safety requirements of the spent fuel pool under LOCA when it encounters an extreme events.

[1]NEI , “B.5.b Phase 2&3 Submittal Guideline” , NEI 06-12 Rev. 2 , Dec 2006
[2]苑穎瑞、曾永信、林志宏、林秉泓、林彥廷，「CDF報告-用過燃料池喪失冷卻能力之熱流分析報告」，核能研究所，2011
[3]“ Fukushima Nuclear Accident Analysis Report ” , Tokyo Electric Power Company, Inc, June 20 , 2012
[4]Gauntt, R.K., Donald Cardoni, Jeff Phillips, Jesse Goldmann, Andrew Pickering, Susan Francis, Matthew Robb, Kevin Ott, Larry Wang, Dean , “ Fukushima Daiichi accident study (status as of April 2012) ” , SAND2012-6173 , 2012
[5]Fluent,“ User's Manual , ANSYS User's Guide 15.0 ” ANSYS Inc , 2013
[6]Fluent,“ User's Manual , ANSYS Theory Guide 15.0 ” ANSYS Inc , 2013
[7]陳彥旭、陳柏諺,「國內核電廠用過燃料池在喪失冷卻時之熱水流分析方法論」，核能研究所，2015
[8]陳柏諺、葉佳霖,「核二廠上池喪失冷卻能力之水位計算書」核能研究所，民國102年
[9]王仲容、陳紹文、施純寬、辜郁庭、曾永信，「核二廠上池喪失冷卻能力之水位計算書」清華大學能環中心，民國105年
[10]D. R. Mowry*, S. Du* , G. K. Roberts , “ The Nuclear Design and Core Physics Characteristics of the Maanshan Unit 1 Nuclear Power Plant Cycle 20 Redesign ” , Westinghouse Electric Company LLC , 2010
[11]Theodore L. Bergman, A.S.L., Frank P. Incropera, David P. DeWitt , “ Fundamentals of heat and mass transfer ”, Wiley , 2007
[12]Shah, M.M., “ Methods for calculation of evaporation from swimming pools and other water surfaces ” , ASHRAE Transactions , 2014
[13]陳柏諺、葉佳霖、蔡豐智，「核三廠燃料池喪失冷卻能力之計算流體力學計算書」，核能研究所，民國104年
[14]A. Machiels, B.C., J. Kessler, F. Rahn, R. Yang, K. Edsinger, B. Carter, “ Summary of the EPRI Early Event Analysis of the Fukushima Daiichi Spent Fuel Pools Following the March 11, 2011 Earthquake and Tsunami in Japan ” , EPRI , Palo Alto , CA, USA , 2012
[15]Boyd, C.F., “ Predictions of Spent Fuel Heatup after a Complete Loss of Spent Fuel Pool Coolant. NUREG-1726 ” Washington , DC: US Nuclear Regulatory Commission , 2000
[16]US Nuclear Regulatory Commission, “ Standard review plan for the review of safety analysis reports for nuclear power plants (NUREG-0800) ” , 1987
[17]王惠偵，「金山電廠用過燃料池TRACE模式建立與應用」，清華大學核子工程與科學研究所學位論文，2014
[18]Adorni, M., Esmaili, H., Grant, W., Hollands, T., Hozer, Z., Jaeckel, B., ... & Tregoures, N.“ Status Report on Spent Fuel Pools under Loss-of-Cooling and Loss-of-Coolant Accident Conditions-Final Report ” , No.NEA-CSNI-R--2015-2 , Organisation for Economic Co-Operation and Development , 2015
[19]Tzu-Chen Hung, V.K.D., Bau-Shei Pei,Yen-Shu Chen,Fengjee P. Tsai, “ The development of a three-dimensional transient CFD model for predicting cooling ability of spent fuel pools ” , Applied Thermal Engineering , 2013
[20]Yan-Ting Lin, B.-Y.C., Pao-Hsiung Chiu,Chin-Jang Chang,Yea-Kuang Chan , “ CFD simulations of the spent fuel pool in the loss of coolant accident ” , HEFAT 2012 , 2012