The accurate knowledge of the time-dependent spatial flux distribution in nuclear reactor is required for nuclear safety and design. The motivation behind the development of parallel methods for solving the energy-, space-, and time-dependent kinetic equations is not only the challenge of developing a method for solving a large set of coupled partial differential equations, but also a real need to predict the performance and assess the safety of large commercial reactors, both these presently operating and those being designed for the future. Numerical results show the efficiency of the parareal method on large light water reactor transient model.