Implementation of Liquid Salt Working Fluids Into TRACE - 14214

In recent years, there has been increasing interest in reactors cooled with high temperature liquid salts. Transient thermal hydraulic analysis of these reactors will be needed both to confirm the designs for normal operation, and to prove their safety under accident conditions. The U.S. Nuclear Regulatory Commission is presently developing and supporting the reactor system safety analysis code TRAC/RELAP Advanced Computational Engine (TRACE). TRACE does not presently have the capability to model these salt-cooled reactor concepts since the thermophysical properties of the salts are not available in the code. In this work, four new liquid salt working fluids were added to TRACE. The salts LiF-BeF₂ and NaF-ZrF₄ are suitable for use as primary coolants in a fluoride salt cooled high temperature reactor (FHR), and the salts LiF-NaF-KF and KF-ZrF₄ are useful in FHR intermediate heat transfer loops. The temperature-dependent density, dynamic viscosity, thermal conductivity, and temperature-independent heat capacity of each liquid salt were added internally into the TRACE code via material property function calls. The implementation was then demonstrated with a TRACE model of the Direct Reactor Auxiliary Cooling System (DRACS) of Oak Ridge National Laboratory's Small Modular Advanced High Temperature Reactor (SmAHTR). (authors)