Eşref BAYSAL, H. Mehmet ŞAHİN, Adem ACIR

$ThO_2-UO_2$ yakıt karışımını içeren candu yakıt çubuklarındaki sıcaklık dağılımının sayısal çözümlenmesi

Bu çalışmada; CANDU yakıt çubuklarındaki sıcaklık dağılımları sonlu farklar metodu kullanılarak incelenmiştir. Temel ısı iletim denklemleri, tanımlanan sınır şartlarıyla birlikte sayısal olarak çözülmüştür. Hesaplamalar sonlu farklar metoduna dayalı HEATING 7.2 bilgisayar kod sistemi kullanılarak yapılmıştır. Elde edilen simülasyon sonuçlarına göre, yakıt çubuklarında % 100 $UO_2$ kullanılması sonucu Model 1 durumunda yakıtın merkezinde eksenel çizgideki maksimum sıcaklık 1764 °C olarak elde edilirken, $UO_2-ThO_2$ yakıt karışımında Model 2, Model 3 ve Model 4 için $ThO_2$ yakıt oranının artmasıyla yakıt çubuklarının merkezindeki eksenel çizgideki sıcaklık değerlerinin azaldığı görülmüş, sırasıyla 1213 °C, 944 °C ve 840 °C olarak elde edilmiştir. Ayrıca; yakıt çubuklarında oluşan sıcaklık dağılımının, yakıt ve zarf malzemesinin ergime sıcaklıklarından daha düşük olduğu tespit edilmiştir.

Numerical analysis of temperature distribution in candu fuel rods consisting of $ThO_2-UO_2$ mixed fuel

In this paper, the temperature distributions in the CANDU fuel rods were investigated using finite difference method. The basic heat conduction equations were numerically solved with defining boundary conditions. The calculations were performed by computer system code of HEATING 7.2 depending on the finite difference method. According to the getting simulation results, in fuel rods, 100 % $UO_2$ using in the case, while the maximum temperature at the axis in the center of the fuel rod gets at 1764 °C for Model 1.On the other hand, in the $UO_2-ThO_2$ fuel mixture for Model 2, Model 3 and Model 4, while increasing $ThO_2$ fuel ratio reducing temperature values were appeared. These values were 1213 °C, 944 °C and 840 °C, respectively. In addition, forming temperature distribution in fuel rods was determined lower than melting temperature point of fuel and clad material.

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1.Şahin, S., Şahin, H.M., Alkan, M., Yıldız, K., "An Assessment of Thorium and Spent LWR-Fuel Utilization Potential in CANDU Reactors" Energy Conversion and Management, 45,1067-1085,2004.
2.Şahin, S., Yıldız K., Acır A., "Power Flattening In The Fuel Bundle of a CANDU Reactor", Nuclear Engineering and Design, 2004.
3.Alkan, M., Reutilization of Nuclear Fuel Wastes, PhD Thesis in Turkish, Gazi University, Institute of Science and Technology, Ankara, Turkey, 2003.
4.Altınok, T., Neutronic Analysis of CANDU Reactors Operating with Rejuvenated Spent Fuel in Catalysed Fusion Reactors, PhD Thesis in Turkish, Gazi University, Institute of Science and Technology, Ankara, Turkey, 1993.
5.Boczar, P. G., Chan, P. S. W., Dyck, G. R., Ellis, R. J., Jones, R. T., Sullivan, J. D., Taylor, P., Thorium Fuel-Cycle Studies for CANDU Reactors, Thorium Fuel Utilization: Options and Trends. Proceedings of three IEAE meetings held in Vienna in 1997, 1998 and 1999, IEAE-TECDOC-1319, 25-41, 2002.
6.Boczar, P. G., Dyck, G. R., Chan, P. S. W., Buss,D. B., "Recent Advances in Thorium Fuel Cycles for CANDU Reactors, Thorium Fuel Utilization: Options and Trends", Proceedings of three IEAE meetings held in Vienna in 1997, 1998 and 1999, IEAE-TECDOC-1319, 104-120,2002.
7.Galperin, A., Todosow, M., "Assessment of Homogeneous Thorium/Uranium Fuel for Pressurized Water Reactors", Nuclear Technology, 138, 111-121, 2002.
8.Hatcher, S. R., "Thorium Cycle in Heavy Water Moderated Pressure Tube (CANDU) Reactors", Atomic Energy of Canada Ltd., Report AECL- 5398,1976.
9.IAEA. "Status and Prospects of Thermal Breeders and their Effect on Fuel Utilization", Technical Report Series No.195, International Atomic Energy Agency, Vienna, 1979.
10.Loewen, E;. P., Wilson, R. D., Hohorst, J.K., Kumar, A.S., Preliminary Frapcon-3th Steady-State Fuel Analysis of ThO2 and UO2 Fuel Mixtures", Nuclear Technology, 136,261-277,2001.
11.Choi, H.B., Rhee B.W., Park, H.S., "Physics study on direct use of spent pressurized water reactor fuel in CANDU (DUPIC), Nuc. Sci. Eng. 126:80,2000.
12.Acır, A., "Investigation on Utilization of ThC and LWR Spent Fuel Mixture in CANDU Reactors", J. of The Faculty of Engineering and Architecture of Gazi Univ., 2005.
13.Tayal, M., Yu, S.D., Manu, C, Aboud, R., Bowslaugh, D., Flatt, L., "Modeling Transient Two-Dimensional Non-linear Temperatures in Nuclear Fuel Using the FEAT Code", Proceedings of the Fifth International Conference on CANDU Fuel, Toronto, Ont., Canada, pp. 352-363, 1997.
14.Yu, S. D. and Xu, S., "Modelling of Three-dimensional Steady State Non-linear Heat Transfer In CANDU Nuclear Fuel" Nuclear Engineering and Design, V.216,165-181,2002.
15.Chun, M.H., Ryu, Y.H., "An experimental and theoretical Thermal Analysis of a Simulated CANDU 37-Element Spent Fuel Bundle with Air Backfill, Annals of Nuclear Energy,25, 1253-1262, 1998.
16.Baysal, E., Investigation of Steady State Three Dimensional Heat Transfer in Candu Fuel Rod Containing Natural Uranium and Thorium Fuel Through Finite Difference Method, M. Sc. Thesis in Turkish, Gazi University, Institute of Science and Technology, Ankara, Turkey, 2003.
17.Yapıcı H., Temperature distribution in mixed ThO2-UO2 fuel rods located in blanket of an inertial fusion energy breeder, Annals Of Nuclear Energy, 29,2187-2209,2002.
18.Yapıcı, H., Ipek, O., Ozceyhan, V., Temperature distribution in nuclear rod and variation of the neutronic performance parameters in (D-T) driven hybrid reactor system, Annals of Nuclear Energy, 28, 1825-1850,2001
19.Yapıcı, H., Ipek, O., Ubeyli, M., "Investigation of the Performance Parameters and Temperature Distribution in Fuel Rod Dependent on Operation Periods and First Wall Loads in Fusion-fission Reactor System Fueled with ThO2", Energy Conversion and Management, 44: 573-595, 2003.
20.Incropera, F., P., Dewitt, D., P., Fundamentals of Heat and Mass Transfer, Purdue University, School of Mechanical Engineering, John Wiley & Sons, 1996.
21.Özışık, M. N., Finite Difference Methods in Heat Transfer, Mechanical and Aerospace Engineering Department, North Carolina State University, 1994.
22.Childs K. W., "Heating 7.2 User's Manual" NUREG/CR-0200, Revision 6, Volume 2, Section F10, ORNL/NUREG/CSD-2/V2/R6, Oak Ridge National Laboratory, 2000.
23.Petrie L. M., "SCALE System Driver", NUREG/CR-0200, Revision 6, 3, Section Ml, ORNL/NUREG/CSD-2/R6, Oak Ridge National Laboratory, 2000.
24. Greene N. M., Petrie, L. M., "XSDRNPM, A One-Dimensional Discrete-Ordinates Code for Transport Analysis", NUREG/CR-0200, Revision 6, 2, Section F3, ORNL/NUREG/CSD-2/V2/R6, Oak Ridge National Laboratory, 2000.
25.http://www.webelements.com/ The University of Sheffield and WebElements Ltd, UK, 2004.