Assessment of Reusing 14-ton, Thin-Wall, Depleted UF{sub 6} Cylinders as LLW Disposal Containers
- ORNL
Approximately 700,000 MT of DUF{sub 6} is stored, or will be produced under a current agreement with the USEC, at the Paducah site in Kentucky, Portsmouth site in Ohio, and ETTP site in Tennessee. On July 21, 1998, the 105th Congress approved Public Law 105-204 (Ref; 1), which directed that facilities be built at the Kentucky and Ohio sites to convert DUF{sub 6} to a stable form for disposition. On July 6, 1999, the Department of Energy (DOE) issued the ''Final Plan for the Conversion of Depleted Uranium Hexafluoride as Required by Public Law 105-204 (Ref. 2), in which DOE committed to develop a Depleted Uranium Hexafluoride Materials Use Roadmap''. On September 1, 2000, DOE issued the Draft Depleted Uranium Hexafluoride Materials Use Roadmap (Ref. 3) (Roadmap), which provides alternate paths for the long-term storage, beneficial use, and eventual disposition of each product form and material that will result from the DUF{sub 6} conversion activity. One of the paths being considered for DUF{sub 6} cylinders is to reuse the empty cylinders as containers to transport and dispose of LLW, including the converted DU. The Roadmap provides results of the many alternate uses and disposal paths for conversion products and the empty DUF{sub 6} storage cylinders. As a part of the Roadmap, evaluations were conducted of cost savings, technical maturity, barriers to implementation, and other impacts. Results of these evaluations indicate that using the DUF{sub 6} storage cylinders as LLW disposal containers could provide moderate cost savings due to the avoided cost of purchasing LLW packages and the avoided cost of disposing of the cylinders. No significant technical or institutional issues were identified that would make using cylinders as LLW packages less effective than other disposition paths. Over 58,000 cylinders have been used, or will be used, to store DUF{sub 6}. Over 51,000 of those cylinders are 14TTW cylinders with a nominal wall thickness of 5/16-m (0.79 cm). These- 14TTW cylinders, which have a nominal diameter of 48 inches and nominally contain 14 tons (12.7 MT) of DUF{sub 6}, were originally designed and fabricated for temporary storage of DUF{sub 6}. They were fabricated from pressure-vessel-grade steels according to the provisions of the ASME Boiler and Pressure Vessel Code (Ref. 4). Cylinders are stored in open yards at the three sites and, due to historical storage techniques, were subject to corrosion. Roughly 10,000 of the 14TTW cylinders are considered substandard (Ref. 5) due to corrosion and other structural anomalies caused by mishandling. This means that approximately 40,000 14TTW cylinders could be made available as containers for LLW disposal In order to demonstrate the use of 14TTW cylinders as LLW disposal containers, several qualifying tasks need to be performed. Two demonstrations are being considered using 14TTW cylinders--one demonstration using contaminated soil and one demonstration using U{sub 3}O{sub 8}. The objective of this report are to determine how much information is known that could be used to support the demonstrations, and how much additional work will need to be done in order to conduct the demonstrations. Information associated with the following four qualifying tasks are evaluated in this report. (1) Perform a review of structural assessments that have been conducted for 14TTW. (2) Develop a procedure for filling 14TTW cylinders with LLW that have been previously washed. (3) Evaluate the transportation requirements for shipping 14TTW cylinders containing LLW. (4) Evaluate the WAC that will be imposed by the NTS. Two assumptions are made to facilitate this evaluation of using DUF{sub 6} cylinders as LLW disposal containers. (1) Only 14TTW cylinders will be considered for use as LLW containers, and (2) The NTS will be the LLW disposal site.
- Research Organization:
- ORNL Oak Ridge National Laboratory (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 814523
- Report Number(s):
- ORNL/CF-00/36
- Country of Publication:
- United States
- Language:
- English
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