Hazards of combustible gases accidentally released from the process plant of HTGR process applications

This report summarizes the preliminary work on reformer explosions for the indirect cycle plant design effort of the High-Temperature Gas-Cooled Reactor for Process Heat (HTGR-PH). Models were completed for the determination of the combustible behavior of the releases (either instantaneous like puffs or continuous like jets or plumes), the amount of combustible material, and the propagation of detonation and shock waves (i.e., blast) as a consequence of potential explosions. A preliminary analysis reveals that (1) incombustible or flammable but nonexplosive mixtures can be formed by accidental releases from the reformer inlet flow and (2) the addition of sufficient steam to the reformer flow renders nonexplosive any accidental release from the reformer area. The explosion of combustible releases is then analyzed with reference to the worst contributor: synthesis gas. The explosions of instantaneous releases, while enroute, are analyzed under different meteorological conditions. The explosions of continuous releases are analyzed in situ for determining the effects on structures and equipment in the vicinity of the jets by considering (1) detonations inside the combustible region of jets and (2) blasts outside the combustible region of jets