AbstractOne attractive concept for future commercial reactors is one of low cost with minimum advanced technology. Cost-minimized reactors with different operating modes are compared to reveal the most cost-minimized reactor with impact of deign parameters on the cost of electricity (COE). Three kinds of operating modes are considered; i.e. first stability region (FS), second stability region (SS) and reversed shear (RS). Deuterium–tritium fueled, 1000 MW(e) reactors with conventional aspect ratio are assumed. Several criteria for the parameter survey are used; for example, (1) thermal-to-electricity conversion efficiency is assumed to be 34.5% with water as a coolant, (2) average neutron wall load must not exceed 5 MW m−2 with a plasma major radius >5 m, (3) 2 MeV neutral beam injector is applied. It is concluded that the RS operating mode is the most cost-minimized. The results indicated that attaining high βN (the Troyon beta coefficient), low q95 (safety-factor on the 95% flux surface), and high fbs (fraction of bootstrap current) is the best way to obtain a cost-minimized reactor. This cost-minimized RS reactor is advantageous because it can be designed without using advanced coil technology nor an advanced cooling system.