Draft report on melt point as a function of composition for urania-based systems

Valdez, James A¹  Byler, Darrin D¹ 

[1] Los Alamos National Laboratory

关键词: CERAMICS;    CONTAINMENT;    CONTAMINATION;    CRUCIBLES;    GRAPHITE;    ORNL;    PHASE DIAGRAMS;    STOICHIOMETRY;    TESTING;    TUNGSTEN;    TUNGSTEN CARBIDES;   

DOI  :  10.2172/1043500
RP-ID  :  LA-UR-12-22042
PID  :  OSTI ID: 1043500
Others  :  TRN: US1203281

学科分类：核能源与工程

美国|英语

来源: SciTech Connect

【 摘 要 】

This report documents the testing of a urania (UO{sub 2.00}) sample as a baseline and the attempt to determine the melt point associated with 4 compositions of urania-ceria and urania-neodymia pseudo binaries provided by ORNL, with compositions of 95/5, and 80/20 and of (U/Ce)O{sub 2.00} and (U/Nd)O{sub 2.00} in the newly developed ceramic melt point determination system. A redesign of the system using parts fabricated from tungsten was undertaken in order to help prevent contamination and tungsten carbide formation in the crucibles. The previously developed system employed mostly graphite parts that were shown to react with the sample containment black-body crucible leading to unstable temperature readings and crucible failure, thus the redesign. Measured melt point values of UO{sub 2.00} and U{sub 0.95}Ce{sub 0.05}O{sub 2.00}, U{sub 0.80}Ce{sub 0.20}O{sub 2.00}, U{sub 0.95}Nd{sub 0.05}O{sub 2.00} and U{sub 0.80}Nd{sub 0.20}O{sub 2.00} were measured using a 2-color pyrometer. The value measured for UO{sub 2.00} was consistent with the published accepted value 2845 C {+-} 25 C, although a wide range of values has been published by researchers and will be discussed later in the text. For comparison, values obtained from a published binary phase diagram of UO{sub 2}-Nd{sub 2}O{sub 3} were used for comparison with our measure values. No literature melt point values for comparison with the measurements performed in this study were found for (U/Ce)O{sub 2.00} in our stoichiometry range.