[en] Energy Incorporated has constructed an analytical model for the combustion of hydrogen in the gas space of a reactor containment. The model is based on a composite reconstruction of several experimental observations of the hydrogen combustion process coupled with a series of conservative assumptions. The model is augmented by quasi empirical correlations that allow determination of the hydrogen concentration corresponding to the lean combustion limit, the concentration limit at which combustion occurs throughout the containment volume and the fraction of hydrogen within the containment that participates in the burns. These correlations include the effects of initial containment pressure, temperature and humidity. The hydrogen combustion model has been programmed for computer solution and the proprietary code is called HYFIRE. It is useful for and has been used for safety analyses and licensing