Abstract: Based on the scheme of the ACP100+ small modular reactor such as the inner PRZ and steel containment, the strategy for the emergency core cooling, pressure controlling in the containment and long-term cooling are proposed. According to the elementary calculation and analysis, the accumulator can be eliminated for the ACP100+ and the safety injection system is simplified. The release of mass and energy can be controlled more easily due to the smaller size of break based on pressure restrained pool and containment pool above the small steel containment. And the long-term residual heat can the taken out through the pool above the containment based on the natural convection and the inherent safety can be enhanced.