The ARIES research program is a multi-institutional project, the goal of which is to determine the economic, safety, and environmental potential of tokamak fusion reactors. The ARIES-I steady-state tokamak reactor is a conceptual, DT-burning, 1000 MWe reactor with a major radius of 6.75 m, a minor radius of 1.5 m, and an average neutron wall loading of 2.5 MW/m 2. The ARIES-I plasma operates in the first MHD stability regime with a toroidal beta of 1.9%. The choice to operate in the first stability regime, with a high aspect ratio and with a low plasma current, leads to the need for high magnetic field to achieve adequate fusion power density ( β 2 B 4). The toroidal field at the plasma center is 11 T and the maximum field at the coil is 21 T. Nonetheless, it is found that the maximum stress in the structural material of these magnets is ∼ 700 MPa and industrially available alloys can be used. The impurity-control and particle-exhaust system is based on a high recycling double-null divertor system. The low-activation silicon-carbide (SiC) composite is used as structural material. The breeder material, Li 2ZrO 3, and the multiplier material, Be, are both sphere-packed between poloidally nested SiC-composite shells. The divertor plates consist of SiC-composite tube shells protected with 2 mm-thick tungsten armor. The first wall, blanket, shield, and divertor are all helium cooled with an inlet coolant temperature of 350°C at a pressure of 10 MPa. The high helium-outlet temperature of 650°C ensures a relatively high gross thermal efficiency of 49%. The ARIES-I design has demonstrated that tokamak reactors have the potential to achieve a high level of safety coupled with a Class-C waste-disposal rating.