[en] MATRA-LMR of thermal hydraulic subchannel analysis code has the three friction factor models to calculate the pressure loss due to the rod friction and the drag of wire-wrap. Among them, the friction factor model by developed S. K. Cheng and N. E. Todreas was modified because of its erroneous implementation into the code. Gunter-Shaw correlation including Suh-Todreas correlation was applied to the horizontal direction. To assessment of these correlations, flow blockage experiment of ORNL THORS was simulated using the MATRA-LMR code. Although the temperature deviation between the prediction and the experiment was 10 .deg. C, the calculation results showed the similar trend to the experiment. A turbulent mixing factor was assessed by two values of 0.01 and 0.038. The change of the factor affect on the temperature of coolant only if the mass fluxes at the adjacent subchannels have great difference. These assessment results require the further improvement of the code. (1) The friction models of the code have to be considered according to whether the wire-wrap is included in the control volume and the direction of wire-wrap. (2) The turbulent mixing factor would be expressed as a function of the difference of mass flux and geometry