The structure of a very strong detonation wave (a shock wave followed by a thermonuclear reaction zone) propagating through a deuterium‐tritium gas mixture is studied. The shock is sufficiently strong so that it heats the gas to a temperature at which thermonuclear reaction probabilities are large. The characteristic times for collisions and reactions are examined to determine when the von Neumann‐Zeldovich model (separate shock and reaction zone) of detonation structure is applicable. Appropriate nuclear reaction kinetics equations are developed for the reaction zone and the effect of energy loss due to bremsstrahlung is included in the analysis. A set of wave structure equations is derived and solved numerically for several different cases. The physical effects expected from a laboratory fast‐shock experiment are examined briefly.