Fire testing of bare uranium hexafluoride cylinders

In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF6) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam x 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam x 30-in.-long cylinders of Monel, and 8-in.-diam x 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF6 fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover the valves failed and UF6 was released. The remaining cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min