The GIF Policy Group established safety and reliability goals for Generation-IV Nuclear Energy Systems, recognizing a gap between high-level safety fundamentals and detailed codes. To address this, the idea of "Safety Design Criteria (SDC)" was proposed in 2010, starting with Sodium-cooled Fast Reactor (SFR) systems. The "GIF Task Force on Safety Design Criteria" (SDC-TF) was set up to draft the SDC and later expanded to develop specific Safety Design Guidelines (SDGs) for SFRs. The SDC-TF has completed most of its missions, producing key safety documents for SFR systems.