Stress evaluation of the primary tank of a double-shell underground storage tank facility

A facility called the Multi-Function Waste Tank Facility (MWTF) is being designed at the Department of Energy`s Hanford site. The MWTF is expected to be completed in 1998 and will consist of six underground double-shell waste storage tanks and associated systems. These tanks will provide safe and environmentally acceptable storage capacity to handle waste generated during single-shell and double-shell tank safety mitigation and remediation activities. This paper summarizes the analysis and qualification of the primary tank structure of the MWTF, as performed by ICF Kaiser Hanford during the latter phase of Title 1 (Preliminary) design. Both computer finite element analysis (FEA) and hand calculations methods based on the so-called Tank Seismic Experts Panel (TSEP) Guidelines were used to perform the analysis and evaluation. Based on the evaluations summarized in this paper, it is concluded that the primary tank structure of the MWTF satisfies the project design requirements. In addition, the hand calculations performed using the methodologies provided in the TSEP Guidelines demonstrate that, except for slosh height, the capacities exceed the demand. The design accounts for the adverse effect of the excessive slosh height demand, i.e., inadequate freeboard, by increasing the hydrodynamic wall and roof pressures appropriately, and designing the tank for such increased pressures