Researchers at CIEMAT, Spain and JRC, Germany have recently published a study exploring the potential risks of storing highly-irradiated spent nuclear fuel when the fuel oxidises. A Linkam THMS600 stage was used to accurately control the temperature under a flow of dried air. Time-resolved Raman spectra were obtained from different locations on the uranium pellet, over the course of several days. Changes between different regions were proposed to be a result of higher local burn up of the oxidation products caused by increased fission. This work could help to reduce the dangers of storing spent nuclear fuels.