Abstract: To explore the damage evolutions and safety thresholds of reinforced concrete (RC) wall in a nuclear power plant subjected to blast loading, eight shots explosion tests were firstly conducted on 1/6-scale RC slab specimens using 2 kg TNT charges. The free-field overpressure-time histories as well as the damage and failure modes of specimens were recorded under varying scaled distances (0.07 m/kg^1/3-0.86 m/kg^1/3) and repeated blast scenarios. Then, the high-fidelity numerical simulations were performed, and the reliability of the adopted finite element analysis method was validated by comparing the overpressure-time histories, failure modes, as well as the spalling and scabbing dimensions of RC specimens with the test data. Finally, based on the validated finite element analysis method, the damage and failure of the prototype nuclear power plant wall under two typical drone-carried TNT equivalents (20 kg and 50 kg) were analyzed, respectively. The corresponding scabbing limit curve of RC wall under these charge equivalents was derived. The study results show that: The scaled RC slab specimens exhibited three typical damage modes at varying scaled distances, i.e., spalling on the front surface with scabbing on the back surface, spalling on the front surface with incomplete scabbing on the back surface, and minor damage on the front surface with cracking on the back surface; Under the repeated blast loading, the spalling diameter on the front surface and scabbing diameter on the back surface of the RC slab specimen increased by 9.36% and 13.46%, respectively, leading to perforation failure; For the prototype nuclear power plant wall subjected to the explosion of 20 kg TNT and 50 kg TNT, the critical scabbing scaled distance ranges were determined to be 0.1 m/kg^1/3-0.2 m/kg^1/3 and 0.2 m/kg^1/3-0.3 m/kg^1/3, respectively.