Monitoring of Corrosion in ORGDP Cylinder Yards

Uranium hexafluoride (UF6) throughout the nuclear fuel cycle is handled and stored in cylinders which are designed, manufactured, and maint\"i.ned in accordance with the ASME Boiler and Pressure Vessel Code for unfired pressure vessels (Section VIII). There are presently more than 40,000 of these cylinders within the DOE Oak Ridge Operations complex currently used for the storage of isotopically depleted material (process tailings). These tails cylinders, in 10.. and 14-ton sizes, are 48 inches in diameter and are constructed of mild steel. Most cylinder storage facilities are open areas adjacent to the enrichment plants where the cylinders are exposed to weather. Mild steel will corrode under these conditions, presenting the need for the monitoring of cylinders in storage to provide assurance that they have not deteriorated to the extent that they no longer meet wall thickness requirements for shipping and handling.