Low temperature accumulation and annealing experiments, in conjunction with electrical resitivity and critical current density measurements, are used to study the ageing of the actinide superconductor PuCoGa5. These measurements reveal that 2-nm sized nonsuperconducting point-like regions are the main damage formed during room temperature ageing; smaller point like defects are irrelevant to transport properties. Defect sizes and densities deduced from experiment agree with Transmission Electron Microscopy observations.