Under contract with the Department of Energy, Rockwell Hanford Operations (Rockwell) conducted a series of studies related to Three Mile Island (TMI) post loss of coolant accident (LOCA) waste handling safety. The key factor in these studies was the control of radiolytic gases, specifically hydrogen and oxygen.

Success was achieved in the prediction of gas generation rates and in the development and application of gas control technologies. That success led to the publication of a “lessons learned” document, providing (1) a step-by-step guide in evaluating potential radiolysis hazards in waste storage and shipment activities and (2) a set of corrective options for preventing or controlling the hazards. The evaluation steps developed in the document are outlined in a functional logic diagram. Several procedures are described which provide safe and effective controls for hydrogen and oxygen levels in containers scheduled for shipment or interim storage. A method is provided to pre-evaluate each control option and select the most cost effective procedure for each case.