South Tank Farm underground storage tank inspection using the topographical mapping system for radiological and hazardous environments

Abstract

During the winter of 1997 the Topographical Mapping System (TMS) for hazardous and radiological environments and the Interactive Computer-Enhanced Remote-Viewing System (ICERVS) were used to perform wall inspections on underground storage tanks (USTs) W5 and W6 of the South Tank Farm (STF) at Oak Ridge National Laboratory (ORNL). The TMS was designed for deployment in the USTs at the Hanford Site. Because of its modular design, the TMS was also deployable in the USTs at ORNL. The USTs at ORNL were built in the 1940s and have been used to store radioactive waste during the past 50 years. The tanks are constructed with an inner layer of Gunite{trademark} that has been spalling, leaving sections of the inner wall exposed. Attempts to quantify the depths of the spalling with video inspection have proven unsuccessful. The TMS surface-mapping campaign in the STF was initiated to determine the depths of cracks, crevices, and/or holes in the tank walls and to identify possible structural instabilities in the tanks. The development of the TMS and the ICERVS was initiated by DOE for the purpose of characterization and remediation of USTs at DOE sites across the country. DOE required a three-dimensional, topographical mapping system suitable for use in hazardous and radiological environments. The intended application is mapping the interiors of USTs as part of DOE`s waste characterization and remediation efforts, to obtain both baseline data on the content of the storage tank interiors and changes in the tank contents and levels brought about by waste remediation steps. Initially targeted for deployment at the Hanford Site, the TMS has been designed to be a self-contained, compact, and reconfigurable system that is capable of providing rapid variable-resolution mapping information in poorly characterized workspaces with a minimum of operator intervention.