Rhenium compatibility with uranium dioxide at elevated temperatures

Abstract

Rhenium has been proposed for application as a cladding material for uranium dioxide (UO2) space reactor fuel because of its ductility, good corrosion resistance, and high melting point (3459 K). Rhenium is also important in reactor design to making proposed space nuclear reactors water submerged, sub-critical. To utilize rhenium as a cladding material it is necessary to know whether it would react with the UO2 fuel at high temperatures. Any reactions that would weaken the cladding such as formation of a eutectic could cause the cladding to fail. However, insufficient test data exist to determine the compatibility of rhenium with uranium dioxide nuclear fuel at the temperatures likely to be encountered in a space nuclear reactor. To answer these questions, mixed powders of Re and UO2 were sintered for 10 hours at 2500 K in a tungsten susceptor. Samples were analyzed by x-ray diffraction analysis, scanning electron microscopy, and energy dispersive x-ray spectroscopy. All analyses indicated no reaction between Re and UO2 nor any interdiffusion of the elements.Rhenium has been proposed for application as a cladding material for uranium dioxide (UO2) space reactor fuel because of its ductility, good corrosion resistance, and high melting point (3459 K). Rhenium is also important in reactor design to making proposed space nuclear reactors water submerged, sub-critical. To utilize rhenium as a cladding material it is necessary to know whether it would react with the UO2 fuel at high temperatures. Any reactions that would weaken the cladding such as formation of a eutectic could cause the cladding to fail. However, insufficient test data exist to determine the compatibility of rhenium with uranium dioxide nuclear fuel at the temperatures likely to be encountered in a space nuclear reactor. To answer these questions, mixed powders of Re and UO2 were sintered for 10 hours at 2500 K in a tungsten susceptor. Samples were analyzed by x-ray diffraction analysis, scanning electron microscopy, and energy dispersive x-ray spectroscopy. All analyses indicated no reaction bet...