The decommissioning of Italy’s Garigliano nuclear power plant has progressed significantly, with the successful completion of the first phase of dismantling the reactor vessel.
This intricate operation involved the removal of contaminated metal components from the deflector, the upper portion of the vessel.
Underwater Operations Ensure Safety
Societa Gestione Impianti Nucleari SpA (Sogin), the Italian state-owned company responsible for nuclear decommissioning, along with its subsidiary Nucleco, initiated the dismantling process in December 2023.
This process involved flooding both the reactor vessel and channel, creating a natural radiation shield to ensure the safety of subsequent underwater dismantling operations.
Meticulous Preparation and Expert Supervision
Prior to removing the vessel head, extensive preparatory work was carried out. This included the restoration of essential electrical, ventilation, and control systems within the reactor building, as well as the activation of the reactor channel flooding circuit.
The removal of the vessel head proceeded under the watchful eye of Italy’s National Inspectorate for Nuclear Safety and Radiation Protection.
Remote-Controlled Precision Dismantling
During the initial phase, specialized underwater equipment, including a pneumatic clamp and mechanical tools operated remotely with high-resolution cameras, was employed to remove and cut the contaminated components.
This reduced their volume and facilitated their handling.
Safe Storage and Future Steps
Following treatment, the components, weighing approximately one tonne, were carefully placed in two high-integrity containers for temporary storage on-site. These containers await transfer to Italy’s planned national repository for radioactive waste.
The next steps in the dismantling process involve removing the internal components of the vessel, followed by the dismantling of the vessel itself. The executive design for the removal of the internal components has already commenced.
Engineering Challenges and Historical Context
Sogin acknowledges the complexity of this undertaking, stating, “This is the most complex activity from an engineering and operational point of view for the decommissioning of a nuclear plant.”
The Garigliano power plant, a 150 MWe boiling water reactor, began operating in January 1964 and was shut down in 1982 following Italy’s decision to phase out nuclear power after the Chernobyl disaster. Sogin was established in 1999 with the mandate to decommission the country’s nuclear sites and manage radioactive waste.
New Waste Storage Facility Underway
In related news, Sogin recently announced the completion of the foundation slab for the DT2 building, a new interim storage facility for waste generated during the Garigliano decommissioning process.
This facility, expected to be commissioned in the first half of 2026, will provide safe storage for low and medium-level radioactive waste from the power plant’s dismantling activities.