Complex sentence: At 2700--2800 ° C the uranium oxide itself melts and the core geometry collapses; this can occur at lower temperatures if the eutectic uranium oxide-zirconium composition gets formed.
Split into simpler sentences: At 2700--2800 ° C the uranium oxide itself melts and the core geometry collapses. This can occur at lower temperatures if a eutectic uranium oxide-zirconium composition gets formed.