Load drop evaluation for TWRS FSAR

Operational or remediation activities associated with existing underground high-level waste storage tank structures at the Hanford Site often require the installation/removal of various equipment items. To gain tank access for installation or removal of this equipment, large concrete cover blocks must be removed and reinstalled in existing concrete pits above the tanks. An accidental drop of the equipment or cover blocks while being moved over the tanks that results in the release of contaminants to the air poses a potential risk to onsite workers or to the offsite public. To minimize this potential risk, the use of critical lift hoisting and rigging procedures and restrictions on lift height are being considered during development of the new tank farm Basis for Interim Operation and Final Safety Analysis Report. The analysis contained herein provides information for selecting the appropriate lift height restrictions for these activities