Almaraz Plant has begun preparations for a second Customized Temporary Waste Repository, or ATI-100, to handle spent nuclear fuel. Since late 2018 the Cáceres facility operated a similar unit capable of holding twenty containers of irradiated fuel; the new facility will be far larger, with the potential to accommodate up to 125 tanks.
After completing the basic project design, the environmental impact study for the project was submitted to the Ministry of Ecological Transition and Demographic Challenge in September. An Environmental Impact Declaration and permissions for construction and site installation are being requested, and the plan will be reviewed by the Nuclear Safety Council, per statements from CNAT, the coordinating body for Almaraz and Trillo nuclear plants. Officials indicate that both authorizations and other required permits must be secured before construction on ATI-100 can begin. The stated objective is to have a fully capable ATI that can continue to drain fuel from storage pools after 2028.
Regardless of the future operating scenario, the construction of the second temporary storage facility is deemed necessary. The existing ATI is operating with twelve full containers, each containing 32 fuel elements, which puts the unit at about 60 percent of its capacity. This means Almaraz has enough headroom to continue operating through the timelines set out in the National Integrated Energy and Climate Plan, with the first reactor scheduled to shut down in late 2027 followed by the second reactor in the same period, and the final phase around 2028.
File photo shows a fuel container being moved toward the Cáceres facility. The image is supplied for illustrative purposes.
Both reactor storage pools are currently near capacity, roughly 90 percent full. If Almaraz extends operation or contemplates dismantling, a new storage installation will be necessary to dry out the remaining high-density waste still accumulating in ponds.
The seventh Radioactive Waste General Plan revision, announced about a year ago, concluded that Central Temporary Storage for waste is not feasible in the current layout and proposed establishing these facilities as replacements for five operating power plants in Spain. Existing repositories must be upgraded, and there is concern regarding the Santa María de Garoña site in Burgos, which faces renewed risk after a decade of paused dismantling. A similar project progressed at José Cabrera in Guadalajara, where demolition activities are nearly complete.
Recent steps by Cofrentes, Ascó, and Vandellós have also begun the ATI construction process. In Almaraz, the waste plan suggests extending the storage period to potentially 2086, with a broader goal of licensing and developing a future AGP deep geological repository.
The new ATI-100 will sit in the northern area of the Almaraz complex, east of the existing installation, and will be significantly larger. The concrete seismic slab will measure 125.1 meters by 32.5 meters, compared to the ATI-20 footprint of 50 by 21 meters.
For ATI-100, Enresa, the agency responsible for radioactive waste management and plant decommissioning in Spain, coordinates with sites lacking ATI capacity, CNAT, and the relevant national bodies to create a uniform storage approach across Vandellós II, Ascó, Cofrentes, and Almaraz. The storage solution chosen uses a container model awarded to the ENSA-Holtec joint venture, which will design, license, support, manufacture, and supply the storage and transport systems under Enresa’s contract. The selected dry storage system is Holtec International’s HI-SOTRM FW Version G, a design already licensed and widely used in North America.