# A Study of the Thermodynamic Properties of Nd-C and Ce-C TRISO Fission Product Binary Systems
## 5 Conclusions  
DSC measurements of Nd-C and Ce-C mixtures were conducted to assess the phase transition temperatures and associated enthalpies of fusion of varying molar concentrations. Of particular interest is the interaction between the rare earth samples and the boron nitride crucibles. The experimental methodology should be further refined to use crucibles that will not adhere to the tested specimens. While previous rare earth experiments in the open literature successfully employed boron nitride crucibles without adhesion, those crucibles were custom-designed and fabricated [23; 52], which may have assisted in mitigating the sample adhesion.  
New data have been added that can be used to support the thermodynamic model of the Nd-C system for the 10 to 40 mol%C portion of the phase diagram. Overlaying measurements in this work with experimental data in the open literature agreed well. Data that can be used to support the thermodynamic model of the Ce-C system was similarly expanded in the 20 to 40 mol%C range, with an additional measurement performed of the Ce\({}_{2}\)C\({}_{3}\) compound that compared well to experimental data in the open literature.  
These results expand upon nuclear fuel thermodynamic databases, such as TAF-ID, to provide experimental data that validate Nd-C and Ce-C Gibbs energy minimization models.  
This will provide a thermodynamic basis for TRISO fuel safety simulations on validating the integrity of the SiC layer, and is expected to improve manufacturing of TRISO fuel particles. However, some data are still lacking in the Nd-C system, and significant gaps remain in the Ce-C system.  
Conceptualization, M.H.A.P. and E.S.S.; methodology, B.W.N.F., R.V. and M.H.A.P.; writing--original draft preparation, R.V.; writing--review and editing, M.H.A.P., B.W.N.F., S.J.C. and E.S.S.; supervision, M.H.A.P. and B.W.N.F.; funding acquisition, M.H.A.P. All authors have read and agreed to the published version of the manuscript.  
This research was undertaken, in part, thanks to funding from the Canada Research Chairs program of the Natural Sciences and Engineering Research Council of Canada, grant (950-231328). Funding for equipment from the Canadian Foundation for Innovation, grant #35712, and the Ontario Ministry of Economic Development, Job Creation Trade, grant #35712, which are greatly acknowledged.  
Data Availability Statement: Data are contained within the article.  
Thanks are due to [PERSON] (previously OTU) and [PERSON] (Illinois Institute of Technology) for their support and productive discussions.  
The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.  
The following abbreviations are used in this manuscript:  
AGR Advanced Gas Reactor  
BSEM Back Scattering Electron Microscopy  
DSC Differential Scanning Calorimetry  
HCP Hexagonal Close-Packed Crystal Structure  
IPyC Inner Pyrolytic Carbon  
OPyC Outer Pyrolytic Carbon  
OTS Oxygen Trap System  
STA Simultaneous Thermal Analyzer  
TG Thermogravimetric  
TGA Thermogravimetric Analysis  
TRISO TRi-structural ISOtropic  
UCO Uranium Observarbide  
US United States  
UTSA University of Texas at San Antonio