Ventilation flow recommendations for Waste Tank 241-SY-101

Radioactive waste stored in Waste Tank 241-SY-101 releases gases that contain hydrogen and nitrous oxide. Concerns have been raised about the possibility of a hydrogen burn event that might damage the tank, which in turn could be postulated to release radioactive materials into the environment. Several investigations are underway to evaluate methods to reduce the likelihood of a hydrogen burn event. One of these methods is to provide additional ventilation to the tank. This report documents analyses that show the effects of ventilation flow rates on hydrogen inventories in the tank. It also shows the resulting tank pressures if the hydrogen is assumed to burn in both air and inert gas atmospheres. A recommended ventilation system flow rate, based on a managed risk approach, is provided. 5 refs., 16 figs., 9 tabs