[en] In this study, the results estimated from ORIGEN2 and ORIGEN-ARP were compared in terms of decay heat, radioactivity, photon spectrum and intensity, neutron spectrum and intensity, nuclide concentration, and hazard index. The reference spent fuels used are as follows; The 17x17 Korean Optimized Fuel Assembly with initial enrichment of 4.0 wt.% ²³⁵U and discharge burnup of 45 GWD/MTU was adopted as a low-burnup representative fuel. For the high-burnup representative fuel, 16x16 Korean Standard Fuel Assembly with initial enrichment of 4.5 wt.% ²³⁵U and discharge burnup of 55 GWD/MTU was chosen. CANDU fuel was also considered. As a result, Negligible differences were shown in total decay heat and neutron shielding concern. However, a remarkable difference was found in radioactivity and concentration for some nuclides which are important in safety assessment of a deep geological disposal of spent fuel. An outstanding difference was revealed in gamma spectrum and intensity as well. Although the source terms were compared in terms of deep geological disposal, it is expected that the findings in this study will be applied to the many nuclear fields to evaluate spent fuel performance, because this report dealt with the most of issues of spent nuclear fuel