Thermophysical Properties of FUNaK (NaF-KF-UF₄) Eutectics

Area of Science:

• Nuclear Engineering
• Materials Science
• Physical Chemistry

Background:

• Growing interest in molten salt reactors (MSRs) necessitates more data on uranium-containing fuel salts.
• Scarcity of thermophysical data hinders MSR design and operability assessments.

Purpose of the Study:

• To provide novel thermophysical data for NaF-KF-UF4 eutectic compositions as potential MSR fuel.
• To bridge the data gap crucial for advancing MSR technology.

Main Methods:

• Experimental measurements of melting point, density, fusion enthalpy, and vapor pressure.
• Extrapolation of boiling point and determination of enthalpy of vaporization from vapor pressure data.
• Comparison of experimental data with literature and thermochemical equilibrium calculations.

Main Results:

• Novel thermophysical data generated for two NaF-KF-UF4 eutectic compositions.
• Good correlation found between experimental data, literature values, and JRCMSD database calculations.
• Validation of the JRCMSD database through comparison with experimental results.

Conclusions:

• The study provides essential data for MSR fuel salt candidates.
• Experimental results contribute to the validation of thermochemical databases.
• Preliminary insights into fluoride salt reactor operability are discussed based on the findings.