Thermal expansions of NpO 2 and some other actinide dioxides
Abstract
Thermal expansions of the stoichiometric actinide dioxides (ThO 2, UO 2, NpO 2 and PuO 2) were investigated between room temperature and 1300 K using a high temperature X-ray diffraction method. The lattice parameter of NpO 2 at high temperatures was expressed as αT (pm) = 542.03 + 4.28 × 10 -3T + 9.07 × 10 -7T2 - 1.36 × 10 -10T3. Based on excellent reproducible data, thermal expansion of NpO 2 was determined. Thermal expansions of the other actinide dioxides showed good agreement with the respective recommended literature values. The linear thermal expansion coefficients ( α) of actinide dioxides calculated at 1200 K were in inverse relation to their melting points. At room temperature, however, the α value of UO 2 was found to be higher than those of the other actinide dioxides and this result was discussed.
- Publication:
-
Journal of Nuclear Materials
- Pub Date:
- May 1997
- DOI:
- 10.1016/S0022-3115(96)00750-7
- Bibcode:
- 1997JNuM..245...72Y