Sogin begins re-encapsulation of uranium-thorium fuel

Between 1968 and 1970, 84 elements of irradiated fuel from the uranium-thorium cycle from the Elk River experimental reactor in Minnesota, USA, were shipped to the Rotondella plant for reprocessing as part of a thorium fuel cycle research programme.

Between 1975 and 1978, a nuclear testing campaign was conducted on 20 of these elements, which produced three different radioactive liquid outcomes; one of these was the so-called final product, consisting of recovered fuel and fission elements in a nitric-based solution. Currently, the liquid radioactive waste present at the site is safely stored in a steel tank contained, in turn, in a very thick reinforced concrete structure.

Societa Gestione Impianti Nucleari (Sogin) has now begun the process of re-encapsulating the remaining 64 elements.

The operation involves transferring each fuel element from its current containment capsules into new capsules suitable for insertion into the two special casks already on-site. The fuel will then be loaded 'dry' into the two casks, which will be safely stored in the Rotondella site's temporary storage facility pending their eventual transfer to the national radioactive waste repository, once it becomes available.

The operations will take place within the plant's fuel storage pool, submerged under a layer of water to ensure natural radiation shielding. Activities will be carried out according to specific engineering procedures designed to guarantee safety throughout all operational phases and to allow for the visual inspection of all elements to verify their structural integrity. The re-encapsulation operations are scheduled for completion by mid-2027.

Sogin said the start of re-encapsulation operations "marks a significant milestone in the 'dry storage' process for this fuel - a key objective of the decommissioning programme for the Basilicata-based facility".

In June 2023, Sogin awarded a contract worth EUR43 million (USD49 million) to a consortium comprising Ansaldo Nucleare and construction firm Monsud SpA for the construction of the Finished Product Cementation Plant (ICPF) at the Itrec facility. The ICPF facility is intended for the cementation of about 3 cubic metres of liquid uranium-thorium solution, referred to as 'final product', resulting from the experimental reprocessing operations performed on fuel during the Rotondella plant's operation.