Today, during the reprocessing of spent nuclear fuel, iodine-129 and carbon-14, two long-lived radionuclides, are managed through regulated discharge. The D-CLIC project, funded as part of the France 2030 actions, is an innovative project that aims to propose a method for conditioning iodine-129 and carbon-14 in the crystalline structure of phosphocalcic apatites. The qualification of this conditioning method is a scientific and environmental challenge. One of the objectives is to validate the long-term behavior of such matrices on inactive materials in environments that may be encountered at a future deep geological disposal site. The mission entrusted to the candidate will be to specify the alteration of these crystalline phases under saturated aqueous conditions for two types of environments, the first representative of the storage area for long-lived intermediate-level waste (ILW) and the second, representative of the storage area for high-level waste (HLW), as a function of different intrinsic and extrinsic parameters.