Nuclear fuel management

​​The operation of nuclear power plants and research reactors takes place through the “burning” of the so-called nuclear fuel. This “burning” is produced by the interaction in the neutron reactor with the materials present in the fuel itself. This interaction involves, among other things, the so-called nuclear fission, that is, the cores of heavy elements, mainly uranium and plutonium (the latter which is not present in nature but generated by neutron irradiation), hit by neutrons and divided into two or more lighter fragments.
Once the life cycle has been completed, the fuel is removed from the nuclear reactor, at this stage it is called “irradiated” fuel. The irradiated fuel contains about 97% of the radioactivity associated with the nuclear site.
The second phase of the fuel cycle is represented by the burning inside the reactor, called service period. It is preceded by the construction of the fuel (front-end), through the mining of uranium and its subsequent treatment and “enrichment”.
The use of the fuel in the reactor, is followed by operations that include cooling the fuel in the pool, for a period of 2 to 5 years, and its subsequent dry storage or its sending to reprocessing; in this second case, the recovered materials, that are uranium and plutonium, can be reused for the manufacturing of new fuel. This last phase is called back-end. 

Once burned and cooled in the pools, the preparatory activity for the most complex decommissioning operations of a nuclear plant is dry storage or reprocessing (back-end phase) of the fuel. In the first case, the fuel is stored in temporary deposits, inside specific containers, and subsequently disposed of at a suitable site (open cycle of nuclear fuel or Once-through Fuel Cycle). In the second case, the fuel is reprocessed, in other words the materials (uranium and plutonium) that can be reused for the production of new fuel are separated and recovered. The latter can therefore be reused in a nuclear power plant (closed cycle of fuel or closed fuel cycle).

Why do we have nuclear fuel in Italy?

The nuclear fuel present in Italy is linked not only to the past time of electricity production from nuclear source, started between the 50s and 80s with the construction of the nuclear power plants of Caorso, Garigliano, Latina and Trino, with the activity of research carried out in the Casaccia, Rotondella and Saluggia plants, but its presence is also connected to the activity of the research reactors located at the ENEA Casaccia Research Center: TRIGA RC-1 (Training, Research, Isotopes, General Atomics - Reactor Casaccia 1), ROSPO (Organic Experimental Power Reactor zerO), RANA (Neutronic Analysis in Water Reactor), RITMO (Reactor Engineering and Technology ZerO Power Materials) and TAPIRO (Rapid Tare Timing at zerO power) and TRIGA Mark II reactor placed inside the LENA (Applied Nuclear Energy Laboratory) of the University of Pavia (currently the only 1st class reactor operating in Italy).

However, Italy was also among the first countries to decide, with the referendums of 1987 and 2011, to renounce the production of electricity from nuclear sources, causing the closure of these plants. 

Sogin has been entrusted, with the Legislative Decree no. 79 of 16th March 1999 on the liberalisation of the electricity sector, with the management of the nuclear fuel used in the Caorso, Garigliano, Latina and Trino power plants and the one linked to the Superphenix project in the French Creys Malville power plant. Subsequently, Sogin also took over the management of materials and fuel present in the former research facilities of Casaccia, Rotondella and Saluggia, in addition to the FN plant of Bosco Marengo. The strategy adopted by Sogin for fuel management follows the guidelines formulated by the Italian Government. Following the Ministerial Decree of 2nd December 2004, Sogin replaced the dry storage option at the plants with the treatment and reprocessing abroad of the remaining fuel still present in Italy, with the exception of the Elk River fuel on the Rotondella site.

The 2004 strategy is confirmed by the guidelines issued on the 28th of March 2006. In the same year, the French and Italian governments signed the Intergovernmental Agreement at Lucca for the treatment of fuel at the La Hague reprocessing plant in France, of the irradiated nuclear energy present at the Caorso, Trino and Garigliano sites, partly stored at the Avogadro Deposit pool in Saluggia. Following this agreement, Sogin signed a transport and reprocessing contract with the French operator AREVA (now ORANO).
How much fuel is irradiated in Italian nuclear plants? Overall, the irradiated fuel deriving from the operation of nuclear power stations is approximately 1,864 tons (weight before irradiation):

  • Caorso –190.4 tons
  • Garigliano –111 tons
  • Latina –1425.5 tons
  • Trino - 137 tons
The management of the fuel cycle plants entrusted to Sogin in 2003 also involved the taking over of the fuel present at various sites:
  • enriched uranium and thorium fuel from the US Elk River plant (64 elements and 15 bars)
  • irradiated fuel deriving from research activities.
To this day, 99% of the irradiated fuel in the Caorso, Latina, Trino and Garigliano plants have been sent to be reprocessed at the Eurochemic plant in Belgium, at the La Hague plant in France and at the Sellafield plant in the United Kingdom. In particular, of the total 1,864 tons produced by nuclear power plants:

  • about 913 tons were reprocessed abroad on the basis of contracts concluded by Enel before Sogin took over and the nuclear materials have already been sold off.
  • around 951 tons are included in the reprocessing contracts with the French company ORANO (formerly AREVA) and the British Nuclear Decommissioning Authority (NDA, formerly BNFL).
Approximately 938 tons of these have already been transferred, with 126 transports:

  • part of the irradiated fuel (about 716 tons) present in the Garigliano, Trino and Latina plants were sent to the Sellafield UK plant between 1969 and 2005;
  • between 2007 and 2010, all the irradiated fuel present in the pool at the Caorso plant (about 190 tons) was sent to the French plant of La Hague; between 2011 and 2013, part of the irradiated fuel from the Avogadro Deposit pool (about 17 tons) - where in 2007 the irradiated fuel of the Saluggia Eurex plant was transferred - and in 2015 all the irradiated fuel present in the power station's pool of Trino (about 15 tons).
A portion of irradiated fuel, about 13 tons, produced by the operation of the Trino and Garigliano power plants, now stored in Italy, still has to be removed. With these last operations the removal of all the irradiated fuel of the Italian nuclear power plants for the reprocessing will be concluded. With regard to the irradiated fuel present in the fuel cycle plants, the current programs stipulates that, once suitably packaged inside shielded metal containers (cask), it is transferred to the National Repository for the dry storage. Almost all of this material is made up of 64 Elk River fuel elements, weighing about 1.7 tons.

Are transports safe?

Il trasporto del combustibile 
Yes. The fuel is shipped inside particular high-resistance shielding metal containers (cask), which are specially made to ensure maximum safety for operators, the population and the environment. Depending on their technical characteristics, casks are used both for the transport and for the storage of irradiated nuclear fuel and for medium and high activity radioactive waste, which remains inside the cask also for disposal in geological deposits. Each transport is carried out in compliance with IAEA international regulations and is subjected to a series of safety regulations issued by the Italian ISIN Authority. The Prefectures of the Provinces involved in the transport, also, issue a specific emergency intervention plan that covers the entire national section of the route.  

Residues and reprocessing materials

The residues of the fuel reprocessed abroad, once treated and conditioned, will return to Italy to be temporarily stored in cask, inside the National Deposit, pending the availability of a geological deposit.
These residues will return as “vitrified” or “compacted” residues, incorporated in fact in a special glass mortar for high activity liquids or, in the case of high activity solids, following a strong volume reduction by pressing.
For the purpose of the return, the Ministry of Economic Development, with the directive of the 10th of August 2009, directed Sogin to proceed with the replacement of the medium and low activity residues deriving from the reprocessing at Sellafield with a smaller, radiologically equivalent volume of high activity vitrified waste to be given to the National Repository. On the 17th of July 2017, Sogin therefore signed an agreement for the replacement and the minimization of these residues with the British operator NDA. Therefore to this date only vitrified waste is stored in the United Kingdom. The option of the replacement involves several advantages, including the return of a single type of waste with a reduction in volumes, reduction in the number and timing of transports and the simplification of all activities for destorage (preparatory phases for the purposes of return), transport and storage of waste. Uranium and plutonium, or nuclear materials recovered from reprocessing, are reused by foreign operators for the production of new fuel.

Global Threat Reduction Initiative

The GTRI (Global Threat Reduction Initiative) was a program aimed at bringing back under the control of the US government some sensitive nuclear materials exported to different countries for industrial purposes (energy production) or scientific research and no longer useful for those purposes, but which may attract the interest of terrorist organizations. These include plutonium or highly enriched uranium materials that were safely stored in three Italian plants: EUREX of Saluggia, IPU and OPEC of Casaccia and ITREC of Rotondella. Italy has therefore joined the GTRI program as it is functional to the decommissioning process of nuclear plants. The removal of nuclear materials on the national territory ended in 2014. To achieve this, GTRI and Sogin have overcome important technical challenges including transport coordination and the development of new glove boxes for plutonium packaging and a new process to convert highly enriched uranium from a solution to an oxide. The US Ambassador to Italy presented Sogin with a plaque of recognition for the quality and effectiveness of its work.