Spain's Council of Ministers on July 27 authorised decommissioning and waste management firm Enresa to launch a tender for a contract for the design, support with licensing, manufacture and supply of a used nuclear fuel storage system for use at the Almaraz, Ascó, Cofrentes and Vandellós II nuclear power plants. The contract will be worth up to EUR220 million (USD260 million).

Additional interim used fuel storage capacity is needed at the Almaraz plant ahead of its decommissioning (Image: CSN)

Currently, all nuclear power plants in Spain - with the exception of Vandellós II - have onsite independent interim storage facilities for used fuel. In addition to the existing facilities, new temporary storage capacities are required to be in operation by 2026 at all the operating plants, except for Trillo. These new dry storage facilities will feature welded metal cannisters enveloped in concrete.

Enresa said the forthcoming tender will be for the supply of a dry storage system for used fuel generated at the Ascó, Cofrentes and Vandellós II plants from 2026 onwards. At the Almaraz plant, the new system will allow the start of the removal of fuel from its storage pools after the permanent shutdown of its two units, scheduled in 2027 and 2028, in order to prepare for the plant's dismantling.

It said the new storage systems will have the same design for all the plants and will be subject to a single licensing process. Enresa said this will achieve savings thanks to economies of scale and the shared use of auxiliary equipment and spare parts, common procedures and training.

"In order to implement these solutions, it takes five years from the start of the tender until they are operational in 2026, according to the schedule provided in the tender," Enresa said.

The new storage facilities will be compatible with any of the temporary storage strategies adopted in the new General Radioactive Waste Plan (GRWP), which is currently being revised. The GRWP is a document setting out the strategies and activities that must be carried out in Spain with regard to radioactive waste management, the decommissioning of facilities, and the economic and financial analysis of these activities. It is approved by the Council of Ministers and reviewed and updated on a regular basis.

The Trillo nuclear power plant has used a cask storage system to house the facility’s used fuel since 2002 on a temporary basis. The installation has concrete walls and roof, and it is able to accommodate up to 80 dual-purpose casks (for storage and transportation).

An interim storage facility has also already been constructed on the site of the José Cabrera plant and is designed for the dry storage of all used fuel unloaded from the reactor. Its construction was essential to the dismantling of the plant, which shut down in 2006. This facility houses 12 modules loaded with used fuel and four extra additional casks containing the most highly radioactive metal pieces from the segmentation of the reactor internals.

At the Ascó plant, an interim storage facility has been constructed for the dry storage of the used fuel unloaded from its two reactors. It consists of two slabs of reinforced concrete, with capacity for 16 storage modules per slab.

Enresa noted that used fuel stored within the onsite interim storage facilities will eventually be transferred to a centralised storage facility. Villar de Cañas in central Cuenca province was officially selected as the location of the Centralised Storage (CTS) in December 2011. In July 2015, the Nuclear Safety Council concluded the location is a suitable site for a national high-level waste storage facility. The CTS has been designed for a 100-year life, although the current GRWP sets out an operational life of 60 years.

Researched and written by World Nuclear News