Considering the design service life of Paks Nuclear Power Plant, the annual quantity of generated spent fuel assemblies and the number of assemblies already stored in the site, it is envisaged that a total number of 25 storage vaults will be required up to 2017, i.e. until the end of the design service life.

The presently applied triangle lattice arrangement of the storage tubes in the vaults will be replaced with a quadratic lattice thus providing 527 storage places rather than the previous 450. The new vaults planned to be constructed in the future will be capable of accommodating 4743 spent fuel assemblies thus, the extension to 25 vaults will result in an increase of the total capacity to 11943 assemblies.

The construction of 33 vaults was envisaged in the construction design of the ISFS facility to provide for the interim storage of a significant part of the spent fuel assemblies produced during the design service life and the extended service life of the reactors. The total number of 33 storage vaults, if constructed, would provide a maximum storage capacity of 16159 spent fuel assemblies.