Centralized Temporary Storage
Almacenamiento temporal centralizado
The medium or long term irradiated fuel Centralized Temporary Storage Facility (CTSG) is a storage system designed to house the spent fuel and high-level radioactive waste from all or various nuclear power plants in the same country for a given period. It is an intermediate stage in the management of radioactive waste for which there are sufficiently developed and proven technologies nowadays, both for storage under water, in pools, and dry storage, in steel or concrete casks or in vaults with air circulating to remove the heat. Normally, this last dry storage technology is possible only after a prior cooling period in the nuclear power plants pools.
Generally speaking, temporary storage facilities are located on the surface or at a depth of relatively few metres. They can be on the site of a nuclear power plant or outside it, and store the fuel from one or more nuclear power plants. The former are called Individualized Temporary Storage facilities (ITS) and the latter, Centralised Temporary Storage Facilities (CTSF). Both types of temporary storage facilities require continuous monitoring and control measures. In this sense, the Centralised Temporary Storage Facilities (CTSF) are the most ideal temporary solution from the security point of view since they allow the monitoring measures to be concentrated on a single facility and are the most convenient ones for leaving the way open for the eventual dismantling of the nuclear power plants themselves.
Whether they are conventional buildings or other types of massive structures, these facilities have a concrete structure as a radiation shield and as security against unauthorised entries. They are normally located in a physically secure area within a perimeter security fence. Within the facility, the use of vaults or chambers enables the storage of a greater number of fuel assemblies at the lowest cost, this being the system generally used for Centralised Temporary Storage Facilities (CTSF) for both irradiated fuel and vitrified high-level radioactive waste. Storage in casks is the most used system in Individualized Temporary Storage facilities (ITS) until the storage capacity on the nuclear power plant site is full.
The results and experience accumulated by the international technical community are able to ensure the temporary storage of irradiated fuel for periods of 50 years or more as long as the monitoring requirements are met and the confinement of the activity is ensured, leaving open the possibility of recovering the fuel assemblies for its management at the end of the temporary storage period. In no case, can this be considered the definitive solution, nor can it be prolonged indefinitely.