TWRS FSAR integrated control decision meetings - January 22 - 31,1997

U.S. Department of Energy (DOE), Richland Operations Office (RL) letter 97-MSD-163 dated January 15, 1997, directed the Project Hanford Management Contractor (Contractor), Fluor Daniel Hanford, inc., to form a joint RL-Contractor Integrated Control Decision Team (ICDT) to evaluate the Tank Waste Remediation System (TWRS) Final Safety Analysis Report (FSAR) accident scenarios that were identified to be above the risk evaluation guidelines (radiological and/or toxicological) defined by the April 8, 1996, letter from J. Kinzer, RL-TWRS (96-MSO-069) to Dr. A. L. Trego, Westinghouse Hanford Company. The ICDT evaluated six postulated accidents from the draft FSAR which had analyzed consequences above the DOE directed risk evaluation guidelines after controls were applied. The accidents were: (1) Organic Solvent Fires; (2) Organic Salt-Nitrate Fire; (3) Spray Leak; (4) Flammable Gas; (5) Steam Intrusion; and (6) Seismic Event. Five of the postulated accidents exceed radiological risk guidelines. Although the postulated steam intrusion accident does not exceed the radiological risk guidelines, it was considered in the ICDT evaluation because its calculated consequences exceed toxicological risk evaluation guidelines. Figure 1 delineates the mitigated and unmitigated risk evaluations performed for the FSAR