of Spent Nuclear Fuel

A tomographic method, using algebraic reconstruction methods, has been examined for verification of the integrity of spent nuclear fuel. Computer simulations were performed where fuel rods have been removed, i.e. water filled, or replaced with fuel-like material. Various geometric patterns of removed or replaced rods have been examined both for BWR and PWR fuel. Two gamma energies, 662 keV from137 Cs and 1274 keV from 154Eu, have been used in the simulations. It is shown that the higher energy was favourable due to its higher penetrability. Various measurement strategies have been examined especially concerning the number of measurements and the level of statistical noise. The simulations point at the possibility of detecting tampering of a fuel assembly on a single rod level. The replacement with fresh fuel or fuel-like material lead to more confident detection of the manipulation comparing to the case where rods have been replaced with water