Development of model and numerical analysis of cask TC 46 with uranium hexafluoride (UF6) in fire conditions

For providing safety of uranium hexafluoride (UF6) transportation in casks, there is need for appropriate experimental and numerical researches aimed to determine UF6 state in the fire conditions. Temperature and pressure are the basic UF6 parameters of interest in terms of the transportation safety. In total, these parameters allow also to evaluate cask strength. Because of the known difficulties in arrangement of experimental researches due to high toxicity of UF6, of great importance is development of techniques and computational codes, which would simulate correctly behavior of UF6 and casks in the conditions of fires. After issue of \"Rules of safe transportation of radioactive materials\" (TS-R-1) of IAEA in 1996, new requirements (item 630) were included in the part of testing of transportation casks under high-temperature effect without break of protective shell (800 °C for 30 minutes) as a result of an accident. Up to this date, no any full-scale tests have been performed with casks intended for mass transportations of UF6 in the world due to high radiotoxicity and chemical risks. Besides, there are no calculation techniques for numerical study of behavior of TC with UF6 in the fire conditions. Presently Russian experts from RFNC-VNIIEF developed a state-of-the-art technique, which allows performing numerical researches and justification of safety of transport casks (TC) with UF6 in the fire conditions without need for tests. Below the authors briefly present the developed technique and the corresponding program complex AJAX- UF6.