Two-Dimensional Modeling of Spent Nuclear Fuel Using FLUENT

Authors: Imane Khalil, Quinn Pratt

Abstract:

In a nuclear reactor, an array of fuel rods containing stacked uranium dioxide pellets clad with zircalloy is the heat source for a thermodynamic cycle of energy conversion from heat to electricity. After fuel is used in a nuclear reactor, the assemblies are stored underwater in a spent nuclear fuel pool at the nuclear power plant while heat generation and radioactive decay rates decrease before it is placed in packages for dry storage or transportation. A computational model of a Boiling Water Reactor spent fuel assembly is modeled using FLUENT, the computational fluid dynamics package. Heat transfer simulations were performed on the two-dimensional 9x9 spent fuel assembly to predict the maximum cladding temperature for different input to the FLUENT model. Uncertainty quantification is used to predict the heat transfer and the maximum temperature profile inside the assembly.

Keywords: Spent nuclear fuel, conduction, heat transfer, uncertainty quantification.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1315947

References:

[1] Moore, R.S., N. K., 1989. Physical characteristics of GE BWR Fuel Assemblies. Tech. rep., Oak Ridge National Laboratory
[2] DOE, 1987. Characteristics of Spent Nuclear Fuel, High-Level Waste, and Other Radioactive Wastes which May Require Long-Term Isolation. Tech. rep., Office of Civilian Radioactive Waste Management, DOE RW-0184.
[3] Saidi, Maysam, A. R., 2010. “Air Pressure Dependence of Natural-Convection Heat Transfer”. Vol. 2, World Congress on Engineering, pp. 1444–1447.
[4] NRC, 2003. Cladding Considerations for the Transportation and Storage of Spent Fuel. Interim staff guidance report for the spent fuel project office of the United States. Tech. rep. Nuclear Regulatory Commission, ISG-11 R3.
[5] Canaan, Robert, K. D., 1998. “A Numerical Investigation Natural Convection Heat Transfer within Horizontal SpentFuel Assemblies”. Nuclear Technology, 123(2), pp. 193–208.
[6] Araya, Pablo, G. M., 2009. “Benchmark of Natural Convection/Radiation Simulations within an Enclosed Array of Horizontal Heated Rods”. Nuclear Technology, 167, pp. 384–394
[7] Cuta, JM., e.a., 2013. Thermal Performance Sensitivity Studies in Support of Material Modeling for Extended Storage of Used Nuclear Fuel. Tech. rep., TRW Environmental Safety Systems, Inc.
[8] Bahney, R., L. T. Spent Nuclear Fuel Effective Thermal Conductivity Report: Prepared for the US DOE, Yucca Mountain Site Characterization Project Office. Tech. rep.
[9] ANSYS, Inc. ANSYS Commercial Release 17.0 User-Manual, 2016.
[10] Debusschere, Bert. e. a., 2015. The Uncertainty Quantification Toolkit (UQTk), 1 ed. Sandia National Labs, Albuquerque, NM.
[11] Debusschere, B. e. a., 2005. “Numerical challenges in the use of polynomial chaos representations for stochastic processes”. SIAM J. Sci. Comput., 26(2), pp. 698–719.