The analysis corresponding to the safety assessment of nuclear plants is made based on a hypothetical lifespan of 40 years.
In order to operate beyond this period, a review of the original analysis needs to be carried out to decide upon the hypothesis of an extended lifespan, and to obtain more knowledge on the actual state of the structures, systems and components of the plant.
This will allow for, if necessary, the adoption of more timely measures for the replacement, repair or mitigation of the deterioration that may have affected the materials.
Therefore, to operate a long-term nuclear plan, a safety assessment needs to be made showing it maintains the safety requirements applicable to its systems and components.