Evaluation of the gas pressure resulting from an ITP waste tank deflagration

The in-tank precipitation (ITP) process will be utilized as one of the steps to prepare high-level radioactive liquid wastes for vitrification in the Defense Waste Processing Facility at the Savannah River site. Hydrogen (H2) and benzene (C6H6) will be generated in the ITP waste tanks (tanks 48 and 49) as a result of radiolysis and decomposition. The structural response of these tanks to a hypothetical deflagration accident is being analyzed as part of the ITP waste tank safety analysis, and this work was performed to define the range of potential gas pressure loadings. The ITP waste tanks are equipped with a nitrogen purge gas system that removes combustible gases from the tank's vapor space and displaces oxygen. The deflagration accident scenario assumes that the purge gas system has failed and that a combustible gas mixture accumulates because of the buildup of combustible gases and inleakage of air.