The high-temperature heat capacity of the (Th,U)O2 and (U,Pu)O2 solid solutions
[1];
[1];
[3];
- Joint Research Centre, Karlsruhe (Germany); Delft Univ. of Technology, Delft (The Netherlands)
- Joint Research Centre, Karlsruhe (Germany)
- Imperial College, London (United Kingdom); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Imperial College, London (United Kingdom)
- CEA, DANS, DPC, SCCME, LM2T, Gif-sur-Yvette Cedex (France)
The enthalpy increment data for the (Th,U)O2 and (U,Pu)O2 solid solutions are reviewed and complemented with new experimental data (400–1773 K) and many-body potential model simulations. The results of the review show that from room temperature up to about 2000 K the enthalpy data are in agreement with the additivity rule (Neumann-Kopp) in the whole composition range. Above 2000 K the effect of Oxygen Frenkel Pair (OFP) formation leads to an excess enthalpy (heat capacity) that is modeled using the enthalpy and entropy of OFP formation from the end-members. Here, a good agreement with existing experimental work is observed, and a reasonable agreement with the results of the many-body potential model, which indicate the presence of the diffuse Bredig (superionic) transition that is not found in the experimental enthalpy increment data.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC52-06NA25396
- OSTI ID:
- 1375163
- Report Number(s):
- LA-UR-16-20239
- Journal Information:
- Journal of Nuclear Materials, Vol. 484, Issue C; ISSN 0022-3115
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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