Because the temperature after 2½ hrs was still rising, this final scenario was run again with an extended time. This predicted that the ceiling temperature levelled off after 8 hours at 440ºC; this temperature is well below that at which the integrity of the engine room ceiling would be considered to be threatened. In none of these seven fire scenarios would the flask be exposed to conditions more severe than those specified in the IAEA Regulatory Thermal Test for an irradiated fuel flask.