Implementation of R134a thermophysical properties for MARS application

System codes like MARS could predict or validate thermo-hydraulic experiments. However current analysis is limited to water because MARS requires thermodynamic property file (tpf) of target material to execute and has limited tpf library. The tpf file contains information of specific volume, internal energy, thermal expansion coefficient, isothermal compressibility, specific heat, and entropy. Refrigerants like R123 and R134a are convenient than water for certain boiling experiments because they have low boiling point and could easily simulate high pressure environment of nuclear power plants. This study aims to generate and implement tpf of R134a utilizing external data source. Thermodynamic properties were written in tpf by direct fitting from the data source while the equations of thermal expansion coefficient and isothermal compressibility were derived from specific volume's fitted equation. The method was totally different from the conventional method of using derivatives of Gibbs function, where tpfh2o is generated using ASTEM subroutines. For validation, modified property file was used to simulate reference's experimental condition, single phase and two phase flow data were compared. Single phase analysis had moderate accuracy while two phase flow showed almost doubled heat transfer coefficient value. Further works will aim for minimizing two phase calculations with parameter study. (author)