The decommissioning of nuclear power plants represents one of the most challenging phases of the nuclear industry lifecycle. This process involves the coordinated implementation of engineering, radiological protection and radioactive waste management activities. Within this framework, the radiological characterization of activated and contaminated structures is essential for planning dismantling operations and demonstrating compliance with regulatory requirements. This work is carried out within the framework of the decommissioning activities of the “Enrico Fermi” nuclear power plant in Trino Vercellese and focuses on the radiological characterization of the Reactor Pressure Vessel (RPV) and its internals. The objective is to analyze the radiological behavior of the main structural components and to provide technical support for the definition of dismantling and radioactive waste management strategies.