Temperature Profile in Fuel and Tie-Tubes for Nuclear Thermal Propulsion Systems [electronic resource]

• Ngôn ngữ: eng
• Ký hiệu phân loại: 629.232 Materials
• Thông tin xuất bản: Idaho Falls, Idaho : Oak Ridge, Tenn. : Idaho National Laboratory ; Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2015
• Mô tả vật lý: Medium: ED : , digital, PDF file.
• Bộ sưu tập: Metadata
• ID: 267017
• Chủ đề: 1. 33 advanced propulsion systems; 2. Nuclear thermal propulsion & tie-tubes & heat tran

Tóm tắt

A finite element method to calculate temperature profiles in heterogeneous geometries of tie-tube moderated LEU nuclear thermal propulsion systems and HEU designs with tie-tubes is developed and implemented in MATLAB. This new method is compared to previous methods to demonstrate shortcomings in those methods. Typical methods to analyze peak fuel centerline temperature in hexagonal geometries rely on spatial homogenization to derive an analytical expression. These methods are not applicable to cores with tie-tube elements because conduction to tie-tubes cannot be accurately modeled with the homogenized models. The fuel centerline temperature directly impacts safety and performance so it must be predicted carefully. The temperature profile in tie-tubes is also important when high temperatures are expected in the fuel because conduction to the tie-tubes may cause melting in tie-tubes, which may set maximum allowable performance. Estimations of maximum tie-tube temperature can be found from equivalent tube methods, however this method tends to be approximate and overly conservative. A finite element model of heat conduction on a unit cell can model spatial dependence and non-linear conductivity for fuel and tie-tube systems allowing for higher design fidelity of Nuclear Thermal Propulsion.