In the tokamak fusion reactor, the four main reactions (D(D,n)3He, D(D,p)T, T(D,n)4He, 3He(D,p)4He) are attractive due to having the largest cross sections than other nuclear fusion reactions. In this paper, we have studied the four main reactions of fusion with considering different concentrations of tritium in tokamak reactor. Numerical results of temperature and density have been obtained on the base of particle and energy balance equations in the zero dimensional model.
