摘要
熔鹽式反應器的發展至今尚有許多議題待解決，包括爐心設計、熔鹽熱傳現象的研究、氟化鹽系統的規劃等問題，皆被認為是未來須必須克服的議題。熔鹽式反應器採用熔融氟化物鹽類為冷卻劑，液體形式之燃料，並與冷卻劑一起混合流動，且在爐心內中子與燃料發生核反應，將核分裂反應能量直接釋放於融鹽中。熔鹽式反應器不論熱流或爐心設計，皆與現有的LWR有相當大的差異。本研究將從爐心熱流的角度上，提供未來在速度分佈器設計上一個思考的方向
本論文採用計算流體力學(Computational Fluid Dynamics)軟體 FLUENT，進行速度分佈器的設計對爐心熱流影響之模擬研究。本研究以Ignatiev 等人於2007年提出之MOSART(Molten Salt Actinide Recycler and Transmuter)模型作為模擬的對象，探討在穩態運轉下速度分佈器之流孔孔徑大小、排列方式與自由面積(流孔面積)比(free area ratio)對爐心熱流場之影響。
本研究共模擬了12種不同的案例，最後並藉由這些案例的分析，提出的建議進行較佳化速度分佈器設計，再以數值模擬確認該一案例為較佳的設計，可以導致爐心具有較均勻的流體溫度分佈及較低的壁溫。分析結果顯示流口尺寸、排列方式及自由面積比，對爐心熱流場有顯著的影響。較小的孔徑速度分布器，使分佈器平板各孔洞獲得較一致的質量流率；而當孔徑較大時，各孔洞質量流率則與孔洞所在平板半徑位置有關。分佈器孔洞於邊緣分佈的位置不同，可導致爐心壁溫分佈呈現明顯的差異；且當速度分佈器設計在自由面積比35%時，可形成較佳的爐心熱流場分佈。此一較佳化設計的速度分佈器，導致最高壁面溫度為985K，平均流體溫度為943K，最高流體溫度為1024K，皆較其他案例理想。
關鍵字: 熔鹽式反應器、速度分佈器、FLUENT、計算流體力學

參考文獻
[1] 中華民國核能協會 http://www.chns.org/s.php?id=8&id2=149
[2] http://nuclear.inl.gov/gen4/msr.shtml
[3] D.Samuel,“MOLTEN SALT COOLANTS FOR HIGH TEMPERATURE REACTORS”, IAEA Internship Report ,2009,6-23.
[4] K. Mitachi, T. Yamamoto and R. Yoshioka, “Performance of a 200 MWe Molten-Salt Reactor Operated in Thorium-Uranium Fuel-Cycle”, Proceedings of GLOBAL 2005, 2005.
[5] S. Delpech, E. Merle-Lucotte ,D. Heuer , M. Allibert, V. Ghetta C. Le-Brun , X. Doligez and G. Picard“Reactor physic and reprocessing scheme for innovative molten salt reactor system.”,Journal of Fluorine Chemistry, 130 ,2009, 11–17
[6] ANSYS Inc., FLUNET 6.2 User’s Manuals, 2005.
[7] D. T. Ingersoll, C. W. Forsberg , L. J. Ott D. F. Williams, J. P. Renier, D. F. Wilson , S. J. Ball, L. Reid, W. R. Corwin, and G. D. Del Cul, “Status of preconceptual design of the Advanced High-Temperature Reactor” ORNL,TM-2004,104 ,2004.
[8] C. W. Forsberg , “Reactors with molten salts: Options and missions”, Frederic Joliot & Otto Han Summer School on Nuclear Reactors”, “Physics, Fuels, and Systems” Cadarache, France,2004.
[9] C. W .Forsberg,E.F. Peterson, and L. Ott , “The Advanced High-Temperature Reactor: High-temperature Fuel, molten salt coolant, and liquid-metal-reactor plant” ,Paper no. 71, 1st Int. Conf. on Innovative Nuclear Energy Systems for Sustainable Development of the World (COE INES-1), 2004
[10] L. Mathieu, D. Heuer, R. Brissot, C. Garzenne, C. Le Brun,D. Lecarpentier, E. Liatard, J.-M. Loiseaux, O. Me´plan,E. Merle-Lucotte, A. Nuttin, E. Walle, and J. Wilson, “The thorium molten salt reactor: Moving on from the MSBR” Progress in Nuc. En. 48 ,2006.
[11] D. F .Williams, M.Tothl,T. Clarnok , “Assessment of candidate molten salt coolants for the Advanced High-Temperature Reactor (AHTR)”, ORNL/TM,2006/12
[12] D.F. Williams , “Assessment of candidate molten salt coolants for the NGNP/NHI Heat-Transfer Loop” ORNL/TM-2006/69 ,2006
[13] J.UHLIR, “Chemistry and technology of Molten Salt Reactors – history and perspectives” , J. Nuc. Mat. 360 ,2007
[14] T.Takeuchi,S.Satake, R.Miraghaie,K.Yuki, and T.Yokomine, T.KUNUGI, N. Moroley, N. B., Abdou, M. A., “Study of heat transfer enhancement/suppression for molten salt flows in large diameter circular pipe Part I: Benchmarking” Fusion Eng. & Des. 81 ,2006
[15] F. P.Hauk, “Design and set-up of a high temperature flow loop for the investigation of heat transfer and pressure loss in a mixed convection regime flow of higher Prandtl number molten salt simulants” Diplomarbeit, UC Berkeley (UNITED STATES OF AMERICA ) & Technische Universität München ,Germany ,2006
[16] P.M.Bardet, and P.F. Peterson, , “Options for scaled experiments for high temperature liquid salt and helium fluid mechanics and convective heat transfer” Nuclear Technology 163 ,2008
[17] V. Khokhlov, V. Ignatiev, and V. Afonichkin“Evaluating physical properties of molten salt reactor fluoride mixtures” ,Journal of Fluorine Chemistry , 130 ,2009 , 30–37
[18] H. Belachgar, A. Nuttin, G.Picard, “HYDROTHERMAL MODELLING FOR THE MOLTEN SALT REACTOR DESIGN OPTIMISATION”,The 11th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics (NURETH-11) , Paper: 227 Popes’ Palace Conference Center, France, 2005.
[19] S. Y. Chiba, K. Yuki, H. Hashizume, S. Toda and A. Sagara, “Numerical research on heat transfer enhancement for high Prandtl-number fluid”, Fusion Engineering and Design, Vol.81, 513-517, 2006
[20] S. Wang, A. Rineiski and W.Maschek, “Molten salt related extensions of the SIMMER-III code and its application for a burner reactor”, Nuclear Engineering and Design, 1580–1588,2006.
[21] V. Ignatiev, O. Feynberg, I. Gnidoi, A. Merzlyakov, V.Smirnov, A. Surenkov, I. Tretiakov, and R. Zakirov, “Progress in development of LI, Be, Na/F Molten Salt Actinide Recycler & Transmuter Concept” , Proceedings of ICAPP, Nice, France, 7548, 2007
[22] W. Maschek, A. Stanculescu, B. Arien, Y. Bai, Ch. Chabert, A.A. Chebeskov, X. Chen, D.F. da Cruz, V. Dekoussar, K. Devan, S. Dulla, V. Gopalakrishnan,O. Feynberg, R. Harish, V. Ignatiev, J. Ko´pha´zi, J. Li, E. Malambu, P. Mohanakrishnan, K. Morita, G. Pandikumar, Y. Peneliau, P. Ravetto, A. Rineiski,M. Schikorr, R. Srivenkatesan, V. Subbotin, A. Surenkov, M. Szieberth, “Report on intermediate results of the IAEA CRP on ‘Studies of advanced reactor technology options for effective incineration of radioactive waste”, Energy Conversion and Management 49, 1810–1819, 2008
[23] 陳宗廷,“CFD應用於HTGR爐心事故熱流分析”,國立清華大學,碩士論文,民國九十八年
[24] 張仲翔,“熔鹽式反應器對錒系元素焚燒能力的評估計算”,國立清華大學,碩士論文,民國九十九年
[25] 謝佾蒼,“核能級石墨材料應用於模擬極高溫氣冷式反應器爐心環境之微結構變化與累積應變能之研究 ”,國立清華大學,碩士論文,民國九十七年
[26] F.P .Incropera, D.P. Dewitt,T.L. Bergman,A.S. Lavine , Third Edition , Fundamentals of Heat and mass Transfer,WILEY,UNITED STATES OF AMERICA ,2007,A17-A23
[27] Adrian Bejia, CONVECTION HEAT TRANSFER , Third Edition, WILEY,UNITED STATES OF AMERICA ,2004,P663
[28] J. R.LAMARSH, INTRODUCTION TO NUCLEAR ENGINNERING , p44-p93,2nd,Addison-Wesley Publishing Company,1985