S.N. HosseinimotlaghS. KianafrazH. ArshadiN. Jamshidi Department of Physics, Islamic Azad University, Shiraz Branch, Shiraz, IranDepartment of Physics, Islamic Azad University, Arsenjan Branch, Fars, Iran hoseinimotlagh@hotmail.com International Journal of Fundamental Physical Sciences (IJFPS) 4 2 43-54 June, 2014 2231-8186 https://doi.org/10.14331/ijfps.2014.330065 In this work, the performance of fusion reactor ITER90H-P with considering D–T and D-3He fuels are examined by writing the dynamics equations on the system reactor. These equations are solved analytically in the steady state to determine optimum conditions for achieving maximum fusion gain. Maximum fusion gain values are found to be 6.01 for D-T and 0.012 for D-3He at resonance temperatures. The study suggests D-T is the more viable fuel currently due to higher gain. Steady, Fusion Gain, Power, Helium, Tritium https://creativecommons.org/licenses/by/4.0/