The HELIOS zero-dimensional code (Version 1.0) is described in detail in the case of deuterium-tritium (D-T) plasmas.

The part of the code described solves in a self-consistent way the thermal equilibrium equation of a D-T thermonuclear plasma coupled to the conservation equation of the helium ash with a He*/E = const. constraint.

Prominent features of the modeling are the following: description of any type of last closed magnetic surface (LCMS) by means of four portions of conics; exact closed form expressions for the poloidal surface, plasma volume, plasma surface, and LCMS length; exact surface and volume integration (for arbitrary aspect ratio) in the approximation of magnetic surfaces similar to the LCMS; parabolic type density profile and two-parameters temperature profile, both with pedestals and finite values at the separatrix; line radiation of light impurities calculated from tabulated radiative power loss functions; scalings for the pedestal temperature, L-H transition, and confinement time; modeling for the divertor thermal load; self-consistent radial build modeling for the plateau duration calculation; and detailed power plant thermal balance.

Applications to ITER and DEMO operation and to inductive reactor design are given.