An earthquake could be a crucial result of nuclear power plants due to the massive power. It is a main point to keep the stability of the system without a radiation material leak from the reactor. For the safety assessment, the system dynamics predict for the random sampling quantification of an earthquake happening due to unexpected characteristics, which is one of the non-linear algorithms. The dynamical information is incorporated with the loop sequence of the time step procedures by the feedback simulations. The plant system factor is the highest value among three factors including estimation and earthquake factors. In the estimation factor, there is the highest value in 2012. In the earthquake factor, there is the highest value in 2028. The maximum value of summation for three factors is in the year 2030, which has the value of 20.52 times (= 389.85/19.00) higher than the initial value and highest than any other value. The tractable quantification for the safety assessment is obtained by a computer package.