Determination of Effective Thermal Conductivities for a Full-Scale Mock-Up of a 217-Element Breeder Reactor Fuel Assembly Subjected to Normal Shipping Conditions

摘要

This report describes a modeling technique to determine effective conductivities and comparison with experimental data that were obtained on a full-scale mock-up of a breeder reactor fuel assembly subjected to conditions that occur during normal shipping. The analysis involved the determination of nonlinear effective conductivities that can be used in pure thermal conduction heat transfer codes to simulate the coupled phenomena of conduction, convection and thermal radiative heat transfer in the gas regions between individual elements. The results obtained in this study indicate that the temperature of the fuel pins in a Liquid Metal Fast Breeder Reactor (LMFBR) assembly, under normal conditions of transport within a shipping cask, can be estimated to within +-35 sup 0 F over the temperature range (400 less than or equal to T less than or equal to 650 sup 0 F) with the use of an effective conductivity within a pure conduction heat transfer code. Results also indicated convection is a dominate heat transfer agent over the experimental temperature range, this finding was not shown in previous reports that analyzed experimental data from heat transfer within simulated breeder reactor fuel pin assemblies since: (1) the previous experiments were conducted at higher temperatures, at which radiation heat transfer dominates; (2) experiments were conducted only at atmospheric pressure; and/or (3) detailed analysis was not performed. (ERA citation 12:010917)