Accession Number : AD0680052

Title :   HIGH TEMPERATURE THERMAL EXPANSION OF UO2 AND ThO2

Descriptive Note : Technical rept. Jul 1967-Jul 1968

Corporate Author : CINCINNATI UNIV OH

Personal Author(s) : Hoch, M ; Momin, A C

PDF Url : AD0680052

Report Date : Oct 1968

Pagination or Media Count : 26

Abstract : The thermal expansion of uranium dioxide and thorium dioxide has been measured between 20 and 2100C using high temperature X-ray diffraction techniques. The thermal expansion of UO2 and ThO2 as measured by x-ray diffraction is identical to that obtained by bulk expansion measurements. Because of this, and because the specific heat of UO2 shows a rapid increase above 1700C indicating a disorder, it must be concluded that the major structural defect is a Frenkel type disorder. This probably involves the oxygen atom moving from the tetrahedral into an empty octahedral position.

Descriptors :   *THERMAL EXPANSION, *THORIUM COMPOUNDS, *URANIUM COMPOUNDS, CRYSTAL DEFECTS, OXIDES, OXYGEN, X RAY DIFFRACTION

Subject Categories : Physical Chemistry
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE