Competition between disorder creation and annealing in fluoroapatite nuclear waste forms

He-ion irradiation simulating α-particle emission, induces crystal defect recovery in fluoroapatite Ca10(PO4)6F2 pre-damaged by Pb-ions. In fluoroapatite loaded with α-emitter actinides, a similar effect is expected. Therefore, the amorphization level in fluoroapatite has been modeled versus disposal time, α-decay fluence and temperature. When loaded with 239Pu and 244Cm, the structural disorder reaches a plateau, which level depends only slightly on α-energies. This level corresponds to an amorphous fraction of approximately 20% of disorder and is independent of the dose rate. The time delay in reaching the equilibrium regime in the disorder production is inversely proportional to the dose rate whereas the dose or the actinide content is not a critical parameter for the magnitude of the equilibrium level.