Developed are the personal Computer/Workstation (PC/WS) versions of NLOOP code which is used in the transient/accident analysis for Westinghouse plants and established are the analysis procedure using the developed PC/WS versions of NLOOP Code. MS Fortran and Demain/OS Fortran complier are used to install the PC Version and Workstation Version respectively. The `on-line graphic` embodied by C language utilizing the basic graphic functions of PC and WS which displays the calculational results in the monitor is also developed. Finally, the analysis procedure is established by developing the auxiliary programs producing the basic data necessary to the documentation rapidly. (Author).