Ascó ISFSI densification project includes the required activities (analysis, licensing and on field works) to achieve that the original ISFSI, without any relevant physical modification, can store 2×2 additional casks. Hence, completion date of the spent fuel pools will be delayed, at least, 18 months, given extra time for the ATI-100 to be available and fully functional.
The project was initially set as a contingency for potential delays in the new ISFSI availability, initially planned for 2025. The project has included reviewing calculations, analysis, official and supporting documents, etc. required to ensure that the new configuration satisfies nuclear safety and radiological protection requirements.
The authorization request was submitted in December 2020, and finally approved by Spanish regulator (CSN) in March 2022. After relocating every cask in their new position in June 2022, the modification has been implemented, obtaining 18 months of additional storage capacity: finally, evolution of ATI-100 projects has shown that this margin or contingency has been necessary and essential to allow continuous operation of Ascó NPP.