IAEA reviews long-term safety of Spain's Ascó plant

The Ascó plant comprises two Westinghouse pressurised water reactor units with an installed power of about 1030 MWe each. Unit 1 entered commercial operation in 1984, with unit 2 following in 1986. Operator Asociación Nuclear Ascó-Vandellós II (ANAV) plans to extend the operation of both units beyond the initial 40-year lifetime.

The Plenary of Spain's Nuclear Safety Council (Consejo De Seguridad Nuclear, CSN) on 28 July approved an extension to the operating licences for Ascó 1 and 2, by nine years (to 2030) and 10 years (to 2031), respectively. The regulator has included 10 conditions to which the operation of unit 1 will be subject in this new period, and 11 conditions for unit 2. CSN said it will soon send a report with its decision to the Ministry for the Ecological Transition and the Demographic Challenge for final approval.

A Safety Aspects of Long-Term Operation (SALTO) peer review is a comprehensive safety review addressing strategy and key elements for the safe LTO of nuclear power plants. SALTO missions complement IAEA Operational Safety Review Team (OSART) missions which are designed as a review of programmes and activities essential to operational safety. SALTO peer reviews can be carried out at any time during the lifetime of a nuclear power plant, though according to the IAEA the most suitable time lies within the last 10 years of the plant's originally foreseen operating period. SALTO and OSART reviews are carried out at the request of the IAEA Member State in which the review is to take place.

A pre-SALTO mission was carried out at Ascó in January 2019. The latest nine-day mission was requested by ANAV. The 11-member SALTO team comprised experts from Belgium, Bulgaria, the Czech Republic, France, the Netherlands, Slovenia and Sweden, and two IAEA staff members.

The team identified good practices that will be shared with the nuclear industry globally, including: the management of a living design basis document to ensure comprehensive configuration management; the innovative and integrated use of ageing management programme data regarding soil movement under safety-related buildings for LTO analysis; and, effectivity assessment of safety-related organisational changes one year after their approval.

It also provided recommendations and suggestions to support the operator in further enhancing safe LTO. These include that the plant should: implement a consistent strategy for the use of ageing management and LTO safety standards; ensure a comprehensive identification and labelling of structures and components within the scope of safe ageing management and LTO; and, develop and implement a comprehensive equipment qualification programme to preserve fulfillment of safety functions during LTO.

"Staff at the plant are implementing preparations for safe LTO in a timely manner and are professional, open and receptive to the SALTO team's recommendations and suggestions for improvement," said team leader and IAEA Senior Nuclear Safety Officer Robert Krivanek. "Most of the ageing management and LTO activities are already in line with IAEA safety standards, and the SALTO team encourages the plant management to implement all remaining activities for safe LTO."

"Our main goal is to obtain an objective and independent assessment of the Ascó plant's preparedness for LTO," said ANAV CEO Jose Antonio Gago. "The SALTO team's evaluation of our activities against IAEA safety standards gives us the best opportunity to achieve this."

The team provided a draft report to ANAV and CSN at the end of the mission. A final report will be submitted to ANAV, CSN and the Spanish government within three months.

The IAEA said plant management indicated an intention to invite a SALTO follow-up mission to the Ascó plant during the third quarter of 2023.