This paper analyzes plasma characteristics for the newly proposed concept of a closed-loop MHD power generation combined cycle system, which is used as a pulse-driven MHD accelerator to accelerate plasma to high velocity, with a nuclear plant. In this paper, since the final goal is for the space propulsion system applications, the performance of a MHD acceleration system is also analyzed by the Q1D analysis program. Results reveal that the radial velocity with the MHD effect is accelerated rapidly at the channel exit, with a calculated maximum velocity of about 4700 m/s. Consequently, specific impulse approximately 480 s and thrust of about 6550 N are estimated. The static gas temperature is evaluated at less than 600 K, while the value of about 1800 K is calculated for the stagnation gas temperature in the MHD channel. (C) 2009 Elsevier Ltd. All rights reserved.