[en] ZEROD integrates in time the volume-averaged electron and ion energy balance equations, as well as particle balance equations for the various ion species. The ion species included are deuterium, tritium, thermal alpha particles, and one impurity species. The code incorporates models for plasma heating via neutral deuterium beam injection, rf heating by waves in the lower-hybrid frequency regime, control of the burn thermal equilibrium, and fueling. Geometric quantities such as the plasma volume, surface area, profile averaging factors, etc., are calculated on the basis of realistic models for the plasma cross-sectional shape, including circles, ellipses, dees, and doublets