Great part of the radioactivity of a nuclear power plant lies in the nuclear fuel used to generate electricity.
Latina facility is a nuclear power plant with MAGNOX and gas graphite reactor fed with natural Uranium.
The reactor was cooled with CO2 (carbon dioxide) and it used graphite to enhance the stability in the fission process and ensure the production of electric energy.
The fuel elements, contained in the core of the reactor, were channelled in specific tunnels made of a stack of graphite.
The reactor, containing the core, is enclosed in a reinforced concrete structure, which also serves as a biological shield against radiations and it is the main structure of the complex. The process of taking the heat from the core and transforming it into steam, was carried out through a circuit of pipes, boilers and fans (blowers). The thermal energy generated from the steam was, first, channelled to the turbines as mechanical energy and, later, to the electric generator to become electric energy.
After the plant was halted, the fuel was removed, and safe maintenance measures were implemented.
The fuel load and unload structures - which allowed replacing old fuel elements with fresh ones without halting the reactor activities – were dismantled in the Nineties. These operations produced about 2,400 tonnes of materials, among which 90% of cementitious materials which were sent to recovery facilities since it was non-radioactive. The remaining 10% consisted of contaminated materials that have been treated and are now stored in the temporary repositories of the plant.
The whole demolition project for the reactor building will be implemented in two different stages, following two authorisation processes. The first stage, almost concluded in terms of authorisations, involves a reduction in the size of the building, as provided for Windscale site (UK); the second stage involves removing graphite, dismantling the graphite-tank and demolishing the building.
Meanwhile, Sogin has launched several activities through specific authorisation processes. As an example, the dismantling of the six pipes (lower and upper), the six blowers and some auxiliary components of the primary circuit. During the dismantling operations, all the process was monitored to minimise the production of radioactive waste and maximise the chance to recover materials, also by adopting decontamination techniques.
After dismantling the boiler in the reactor building, the biological shield will be sealed, and a new ventilation and dehumidification closed-circuit system will be installed to avoid oxidation and corrosion of the vessel and plants.
Between 2023 and 2025, some premises of the reactor building will be adapted, in terms of structure and plants, to temporary repository for radioactive waste. In this way, the site will have more temporary storage capacity, useful to complete subsequent decommissioning operations without building new structures.
Stage I will be completed between 2025 and 2027 through the decommissioning of structures and the reduction of the reactor building height, from 55 to 35 metres.
When the National Repository will be available, the Stage II for the reactor building decommissioning will be launched.
Stage II will end with the release of the site free of radiological risks. This status will be achieved after the dismantling of all structures and the shipment of radioactive waste to the National Repository, an operation that will also lead to the demolition of the new temporary repository.