External RC containment vessel of nuclear power plant is considered as a vital structure in the nuclear plant. The main function for the external RC containment is to prevent the escape of radiation into the external environment. The external RC containment of NPPs is subjected to impact of an aeroplane Boeing 707-320 acting on 16 exterior nodes at a vertical distance of 30m measured from the top of the foundation level. The problem in this research is the damage generated due to the impact of missile on external RC containment which can escape the radiation into the external environment. The response for RC containment was conducted with respect to stresses, displacement, velocity and acceleration after the impact. The objective is to increase the compressive strength of concrete in order to reduce the damage for RC containment due to impact of missile compared to concrete with a compressive strength of 30 Mpa. It was observed that the damage affects only the impact region of the RC containment. Parametric numerical modelling was conducted using ANSYS program for concrete having different compressive strength for external RC containment. It was observed that the effect of different compressive strength has a great result on the displacement, velocity and acceleration for RC containment due to impact of Boeing 707-320.