An International Atomic Energy Agency (IAEA) team of experts has completed a follow-up Safety Aspects of Long-Term Operation (SALTO) mission to units 1 and 2 of the Laguna Verde nuclear power plant in Mexico. The team reviewed the plant's response to recommendations and suggestions made during a SALTO mission in 2019.

Laguna Verde (Image: CFE)

A SALTO peer review is a comprehensive safety review addressing strategy and key elements for the safe long-term operation (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, although according to the IAEA the most suitable time lies within the last ten years of the plant's originally foreseen operating period. SALTO and OSART reviews are carried out at the request of the IAEA member country in which the review is to take place.

Laguna Verde 1 began commercial operation in 1990 and unit 2 in 1995. Together, the two boiling water reactors provide around 4% of Mexico's electricity. The operator of the plant - the Comisión Federal de Electricidada (CFE) - has already obtained a licence renewal to extend the operating lifetime of unit 1 from 30 to 60 years. CFE has also applied to extend operation of unit 2 to 60 years.

A five-member team - comprising experts from Argentina, Bulgaria, Czech Republic and Germany and one IAEA staff member - has now completed a four-day mission to reviewed Laguna Verde's response to recommendations and suggestions made during the 2019 SALTO mission. One observer from Netherlands and one from Sweden also participated.

The team said the plant had: improved ageing management of mechanical components, civil structures and buildings; developed and implemented a comprehensive training programme for ageing management; and improved the process for data management in support of long-term operation.

The team noted that further work is necessary by the plant to: perform a comprehensive periodic safety review to identify potential safety improvements for LTO; and fully implement a programme to confirm resistance of electrical components to harsh conditions, a so-called equipment qualification programme.

"The team observed that the operator is preparing the plant for safe LTO in a timely manner," said the team leader and IAEA Nuclear Safety Officer Martin Marchena. "Following the recommendations made by the SALTO team in 2019, the plant has made significant improvements in the area of ageing management and has shown continued commitment to prepare for safe LTO. The SALTO team encourages the plant management to fully address the remaining findings from the 2019 SALTO mission and implement all activities for safe LTO."

The plant management expressed determination to address the areas identified for improvement and to continue cooperation with the IAEA.

"We appreciate the IAEA's support to our plant in ageing management and continuous improvement in our safe operation during LTO," said Laguna Verde site director Cesar Amador. "The results of this mission will help us maintain a high performance in our activities for safe LTO."

The team provided a draft report to the plant management and Mexico's regulatory authority, the Comision Nacional de Seguridad Nuclear y Salvaguardias (CNSNS), at the end of the mission. A final report will be submitted to the plant, CNSNS and the government within three months.

Researched and written by World Nuclear News