A 650-MW(electric) deuterium-tritium fusion reactor, KARIN-I, has ten moving plasma rings, which are produced by relativistic electron beam injection, heated by a major radius compression, and transported into a linear cylindrical burning section by annularly flowing liquid lithium outside the silicon carbide first wall The liquid lithium not only stabilizes the tilting motion of the rings but also works as the tritium breeder and the main coolant. Energy from the ash-accumulated rings is efficiently recovered at the exit during the major radius expansion. The linear alignment of reactor components ensures easy assembly and disassembly, and also provides for easy maintenance. These features of the reactor result in a net electric output power of 650 MW(electric) with overall plant efficiency of 30%.