The propagation and absorption of second harmonic ion cyclotron range of frequency (ICRF) waves in NBI heated plasmas are investigated for the regime of plasma parameters in JT-60. The quasi-linear diffusion in the velocity space of ions is taken into account. The Fokker-Planck equation and the kinetic wave equation are numerically solved to obtain the spatial profile of the velocity distribution function and the power deposition profile in a self-consistent manner. The calculation of the power partition rate includes two processes: the direct absorption of the wave through wave-particle interactions and the power transfer due to Coulomb collisions. The power partition between electrons and ions is strongly affected by the plasma density and the RF power. The plasma temperature and the NBI power have some influence on power partition and tail formation in the experimental conditions of interest. The acceleration of the injected particles by ICRF heating is studied. The tail temperature, which is defined by the gradient of the velocity distribution function of tail ions, and the total stored energy of the plasma are calculated and the dependence on the plasma parameters is analysed.