HANFORD DOUBLE SHELL TANK (DST) THERMAL & SEISMIC PROJECT BUCKLING EVALUATION METHODS & RESULTS FOR THE PRIMARY TANKS

Abstract

This revision is to include the independent reviewer comments shown in Appendix D. Summary and in Sections 5.6, 6.3, 6.4.1, 6.4.3,7.1, 7.2, and 8.0 of this report. ;;1. Revisions to the buckling analyses in response to the review comments are contained in this Executive Approved For Public ReleaseA-6002-767 (REV 1) Tank Farm Contractor (TFC)(1) Document Number: RPP-RPT-28967 Page I RECORD OF REVISION Executive SummaryThis report documents a detailed buckling evaluation ofthe primary tanks in the Hanford double-shell waste tanks (DSTs), which is part of a comprehensive structural review for the Double-Shell Tank Integrity Project. This work also provides information on tank integrity that specifically responds to concerns raised by the Office ofEnvirornnent, Safety, and Health (ES&H) Oversight (EH-22) during a review of work performed on the double-shell tank farms and the operation ofthe aging waste facility (AWF) primary tank ventilation system.The current buckling review focuses on the following tasks:• Evaluate the potential for progressive I-bolt failure and the appropriateness ofthe safety factors that were used for evaluating local and global buckling. The analysis will specifically answer the following questions: Can the EH-22 scenario develop ifthe vacuum is limited to -6.6-inch water gage (w.g.) by a relief valve? What is the appropriate factor of safety required to protect against buckling ifthe EH-22 scenario can develop? What is the appropriate factor of safety required to protect against buckling ifthe EH-22 scenario cannot develop?• Develop influence functions to estimate the axial stresses in the primary tanks for all reasonable combinations oftank loads, based on detailed finite element analysis. The analysis must account for the variation in design details and operating conditions between the different DSTs. The analysis must also address the imperfection sensitivity ofthe primary tank to buckling.• Perform a detailed buckling analysis to determine the maximum allowable differential pressure for each ofthe DST primary tanks at the current specified limits on waste temperature, height, and specific gravity.Based on the I-bolt loads analysis and the small deformations that are predicted at the unfactored limits on vacuum and axial loads, it is very unlikely that the EH-22 scenario (i.e., progressive I-bolt failure leading to global buckling ofthe tank under increased vacuum) could occur.Based on the buckling analysis contained in this report, the current limits on the maximum vacuum level of 6-inch w.g. for the AY, AZ, SY, AN, and AW tanks and 12-inch w.g. for the AP tanks are acceptable given the current lack of corrosion in the tanks and the expectation that the maximum waste temperature will not exceed 250°F. These limits are predicated on maintaining the minimum allowable waste level at 6 inches for the AY, AZ, SY, AN, and AW tanks and 12 inches for the AP tanks to preclude bottom uplift from occurring. For this analysis, the occurrence of maximum tank vacuum was classified as a s...