Behavior of a UF6 container during a fire - I: Analysis and phenomenological interpretation of Tenerife experimental results

To improve the knowledge of the behavior of a UF6 container during afire, a n experimental project called Tenerife was conducted by the Commissariat a l'Energie Atomique. Three tests with UF6 with different kinds of heating an d temperature furnaces were carried out. The main information obtained from monitoring temperature and pressure during the heating rests is as follows : 1. The presence of a strong thermal contact resistance at the solid UF6-ste el interface. 2. The rapture of the solid crust at the top of the container, a crust form ed during container cooling after filling, for a pressure reaching 1.5 bars (triple point). This leads to the beginning of boiling heat transfer and n otably film boiling, followed by transition boiling and nucleate boiling. 3. The appearance of the liquid stratification with the beginning of nuclea te boiling. If carl accelerate the rise in pressure because of the reductio n of mass transfer by condensation to the liquid-gas interface. This strati fication is preserved with the natural convection regime that replaces the nucleate boiling after the end of heating. 4. After rupture of the upper UF6 crust, the pressure increase may be delay ed by different wetting of the UF6 on the steel wall. Also, these tests were allowed to build and validate a scenario that has be en reproduced in a numerical model.