Round Robin Measurements of Molten Salt Properties for LiF-NaF-KF (FLiNaK) and NaCl-KCl Mixtures

The development, operation, and regulation of nuclear
reactors
that utilize molten salts as fuel or as heat transfer media require
knowledge of the thermal properties of the salt systems and quantification
of the corresponding uncertainties. Knowledge of molten salt properties
is also necessary for applications in material synthesis, processing,
separations, solar thermal power generation, and energy storage. A
round robin was conducted with national laboratory and university
participants from twenty-one laboratories in five countries to compare
property measurements, to better understand uncertainties, and to
identify possible best practices. Two salt mixtures, each from a common
batch, were distributed to participants for evaluation: equimolar
NaCl-KCl and 45.0LiF-13.7NaF-41.3KF mol % (FLiNaK). Measurements were
performed to determine the major constituent composition, oxygen content,
density, thermal expansivity, melting point, and thermal conductivity.
Error analysis was performed on each measurement for uncertainty quantification
for each type of property that was explored. The resulting discussion
of the methodologies used in this work is meant to lay the groundwork
for the development of standard methods and reference materials for
future high-temperature property measurements on halide melts.