[en] This paper presents a new secondary loop of nuclear power plant system, including the main components of turbine, condenser, feed pump, and heater, with RELAP5 code. The research of the single component model adaptive authentication analysis and the local computing ability of the code have been studied. The results show that the steady state calculation results of the RELAP5 code are basically consistent with the design value, and the dynamic calculations are also able to meet the calculation accuracy request of the main components in secondary loop. (authors)