As there is no legal or administrative limitation as regards the establishment of the operating life of NPPs, with consequently no fixed operation period established, the NPP operating licenses/permits are renewed periodically through on-going assessments and PSRs. The PSRs provide a global evaluation of the plant safety (including the analysis of aspects such as compliance with the standards in force, plant specific and industry operating experience and
updating the safety evaluation and improvement programmes), and also the PSR is the main tool used by the nuclear regulatory authorities to establish the additional requirements for any new operating license period.

In Spain, PSR is used as a basis for renewal of the operating licence for all NPPs. Safety Guide 1.10 of the Spanish nuclear regulatory authority (CSN) establishes the safety issues to be reviewed and resolved to obtain a new operating license for the next period.

The regulatory process, based on on-going assessment and PSRs, includes the necessary mechanisms, and provides a reasonable guarantee that all aspects potentially affecting plant safety or public health are incorporated into the plant licensing bases.

Conditions associated with an operating license in place state that, in the case of applying for a 10 additional years of operation, a new PSR must be performed and submitted to CSN for approval three years before the end of the current operating term. If the new operating period pertains to the operation of the NPP beyond the design life, the main objective of the new PSR will be to determine whether ageing of certain SSCs is being effectively managed so that required safety functions are maintained, and whether an effective AMP is in place for continued operation. Additionally, Time limited ageing analysis(TLAA) must be identified and evaluated in order to demonstrate that it will remain valid for the new period of operation.

The scope of the PSR has been reviewed by the CSN in order to incorporate other aspects related with the continued operation beyond the design life. In order to accomplish this, it has been concluded that the best basis and most detailed international reference for establishing the fundamental requirements for renewal of the operating license beyond the design life is the US regulation 10CFR54 (LR). Therefore, the LR methodology constitutes the supplementary process that has been incorporated to the specific PSR to be performed when applying for a renewal of the NPP operating license exceeding the original design life.