Robert Alvarez, "Managing the Uranium-233 Stockpile of the United States," Science & Global Security, 21, no. 1, (2013): 53-69.
The United States produced about 2 tons of uranium-233, a weapons-useable fissile material, as part of its military and civilian nuclear program. Of that, 1.55 tons was separated at costs estimated to be between $5.5 and $11 billion. Of the 1.55 tons, approximately 96 kg of uranium-233 may be unaccounted for. There are also varying site-specific estimates suggesting that material control and accountability of the U.S. uranium-233 inventory needs to be more stringent. About 428 kg of uranium-233 is stored at the Oak Ridge National Laboratory (ORNL), in Tennessee at Building 3019, a 69-year-old structure which DOE describes as the oldest operating nuclear facility in the World and one that does not meet current safeguards and security requirements. Currently, the U.S. Department of Energy's (DOE) goal for disposition of the 428 kg is 2018, more than 20 years after significant environmental, safety, and security vulnerabilities were first officially acknowledged. To meet this goal, DOE plans to waive its own waste acceptance criteria to allow direct shallow land disposal of a large portion of the uranium-233 by August 2014. Granting a disposal waiver sets a bad precedent for international safeguards and standards for the disposal of reprocessed wastes containing high concentrations of fissile materials.