This paper reports on a comparative analysis of the magnetic fusion energy systems based on aneutronic D–3He fuel. The power balance for a reactor is described for plasma confinement inside closed field lines (region called separatrix). Numerical model of the fusion power density energy balance condition is considered for the closed magnetic traps (tokamak, spherical tokamak, stellarator, and compact toroid). D–T, D–3He, and D–D (catalyzed) fuel cycles are discussed. The conceptual designs use a D–3He fuel cycle and require advances in technology and physics for economical attractiveness. Neutronic aspects and main parameters are presented. Results from the sys-tems analysis are summarized, and a comparison with the D–T-fueled tokamaks is included. The application of the plasma and engineering physics to the D–3He fuel cycle, however, is expected to produce a design that is competitive with fissile and fossil power plants.