Investigation of UF6 behavior in a fire

Reactions between UF6 and combustible gases and the potential for UF6-filled cylinders to rupture when exposed to fire are addressed. Although the absence of kinetic data prevents specific identification and quantification of the chemical species formed, potential reaction products resulting from the release of UF6 into a fire include UF4, UO2F2, HF, C, CF4,COF2, and short chain, fluorinated or partially fluorinated hydrocarbons. Such a release adds energy to a fire relative to normal combustion reactions. Time intervals to an assumed point of rupture for UF6-filled cylinders exposed to fire are estimated conservatively. Several related studies are also summarized, including a test series in which small UF6-filled cylinders were immersed in fire resulting in valve failures and explosive ruptures. It is concluded that all sizes of UF6 cylinders currently in use may rupture within 30 minutes when totally immersed in a fire. For cylinders adjacent to fires, rupture of the larger cylinders appears much less likely