High temperature phase transition of mixed (PuO2 + ThO2) investigated by laser melting

High temperature phase transition of mixed (PuO2 + ThO2) investigated by laser melting

Böhler, R.
Cakir, P.
Benes, O.
Hein, H.
Konings, R.J.M.
Manara, D.

Applied Sciences

RST/Radiation, Science and Technology

2014-10-25

A laser heating approach combined with fast pyrometry in a thermal arrest method was used to provide new data for the melting/solidification phase transition in mixed (PuO2 + ThO2) at high temperature. At low concentration of ThO2 in PuO2 a minimum in the solidification temperature in the pseudo binary (PuO2 + ThO2) was observed. The minimum was found around a composition with 5 mol% ThO2. Phase transition temperatures of other compositions are closer to an ideal solution behaviour. To detect changes in the material a complete investigation with electron microscopy, Raman spectroscopy and powder X-ray diffraction was done. Raman vibration modes were found, that are characteristic for materials containing PuO2, and high temperature segregation effects during solidification were described. The results obtained in the present work are compared to other mixed actinide dioxides and compared to the ideal solution case for this system. The presented results show the importance of the high-temperature oxygen chemistry in this actinide oxide phase.

actinide alloys and compounds
phase transitions
phase diagrams
(Thorium + plutonium) dioxide

http://resolver.tudelft.nl/uuid:635053b5-ff67-4411-b258-7e2c87f2e60b

https://doi.org/10.1016/j.jct.2014.10.006

Elsevier

Journal of Chemical Thermodynamics, 81, 2015

Institutional Repository

journal article

(c) 2014 The Authors
This is an open access article under the CC BY license