Independent Review of Tank 241-AY-101 Fitness for Service

Video inspections in the annulus of Hanford double-shell waste storage tank 241-AY-101 in 2001 and earlier showed rust over large areas of the primary and secondary tank walls. These observations led to extensive on-destructive inspections and analyses to determine the extent and severity of the corrosion and correction of several operational deficiencies that contributed to the problem. PNNL has performed an independent review of the accumulated evidence from these efforts to determine whether unacceptable conditions were corrected and the current condition of the tank meets or exceeds technical and operational requirements. The findings of this review are the subject of this report. The conclusion is that AY-101 is fit for service without restriction subject to several recommendations for further inspections and analyses.