The ongoing nuclear program in Korea is for large-scale electricity generation, which is mainly relying on PWR systems. KSNPP (Korean Standard Nuclear Power Plant) was developed as a standardization effort of existing 1,000 MWe-size PWR systems, and its improved concepts have been progressively adopted in each unit under present construction and in planning stage up to the year of 2006. This paper presents the program of adopting passive safety features in the advanced nuclear systems that will be introduced in Korea beyond the year of 2006. The advanced nuclear systems introduced in this presentation are KNGR (Korean Next Generation Reactor) which is a 1,300 MWe-size PWR of advanced concept, its follow-up units in post-KNGR era, and SMART (System-Integrated Modular Advanced Reactor) which is a 330 MWt-size multipurpose integral-type reactor. In designing these advanced nuclear systems, the safety objective is to keep the risk to the general public within the level of 10(-7) to 10(-6) per reactor-year, and the economic objective is to secure 20%2cost advantage over competing energy sources. The additional adoption of passive feature is decided based upon cost-benefit studies as long as the safety of a nuclear system is within the acceptable range. Fluidic device, passive secondary condensing system, fusible plugs, and catalytic hydrogen ignitors are the specific passive safety features which are decided to be adopted for KNGR design. R&D efforts are still in progress in the areas of passive shutdown decay heat removal, passive safety injection, and passive containment cooling Tor further improvement of safety in KNGR design; and innovative ideas are recommended in SMART design.