Testing program for the model 21 PF-1 protective overpacks

A testing program, supported by an international group of owners of the model 21PF-1 protective overpacks, was held in 1996 as part of a re-certification effort for these packagings. The DOT-21PF-1 and the NCI-21PF-1 overpacks are used throughout the world to ship uranium hexafluoride. In recent years, the shipping packages, consisting of a model 30B cylinder within a protective overpack, came under intense scrutiny from the U.S. Department of Transportation (DOT) and the U.S. Nuclear Regulatory Commission (NRC). This was a result of changes that had been made in the foam formulation used for fire protection of these overpacks. Subsequent testing indicated that, at certain orientations, the overpacks may not adequately protect the cylinder valve from the 30 foot (9 meter) drop and puncture testing required by the regulations, 10 CFR Part 71. With the assistance of Transnuclear, Inc., which served as the technical lead for the program, an extensive test plan was developed and implemented. After several months of preliminary testing and related design changes, full scale compliance testing was performed on the overpacks. The testing program, designed in accordance with the hypothetical accident conditions of 10 CFR 71 and IAEA Safety Series 6, consisted of drop and puncture testing, a fully engulfing fuel fire and subsequent leak testing. The packages performed well during the tests and the test results showed that, with the VPD installed, both the DOT-21 PF-1 and the NCI-21PF-1 overpacks successfully protected the cylinder valve. Complete Safety Analysis Reports for the DOT-21PF-1 and the NCI-21PF-1 packagings were submitted to the DOT and NRC, respectively. The Certificate of Competent Authority for the DOT-21PF-1 overpack was received in June 1997 and the Certificate of Compliance (CoC) for the NCI-21PF-1 packaging was received in September 1997. THe successful completion of the re-certification effort allows the UF6 industry to continue using the model 21PF-1 overpack. (authors)