Post Irradiation Examination
![Temperature profile for a 20 mm diameter fuel pellet with a power density of 250 W per cubic meter. Note the central temperature is very different for the different fuel solids.](/Images/godic/202502/03/Rim200pd250rad1000fueltemp3531.png")
![Temperature profile for a 26 mm diameter fuel pellet with a power density of 250 W per cubic meter.](/Images/godic/202502/03/Rim200pd250rad1300fueltemp3531.png")
![Temperature profile for a 32 mm diameter fuel pellet with a power density of 250 W per cubic meter.](/Images/godic/202502/03/Rim200pd250rad1600fueltemp3531.png")
![Temperature profile for a 20 mm diameter fuel pellet with a power density of 500 W per cubic meter. Because the melting point of uranium dioxide is about 3300 K, it is clear that uranium oxide fuel is overheating at the center.](/Images/godic/202502/03/Rim200pd500rad1000fueltemp3531.png")
Post Irradiation Examination (PIE) is the study of used nuclear materials such as nuclear fuel. It has several purposes. It is known that by examination of used fuel that the failure modes which occur during normal use (and the manner in which the fuel will behave during an accident) can be studied. In addition information is gained which enables the users of fuel to assure themselves of its quality and it also assists in the development of new fuels. After major accidents the core (or what is left of it) is normally subject to PIE in order to find out what happened. One site where PIE is done is the ITU which is the EU centre for the study of highly radioactive materials.