IAEA reviews long-term safety of Sweden's Ringhals 3

18 September 2020

An International Atomic Energy Agency (IAEA) team of experts today completed a review of the long-term operational safety of unit 3 of the Ringhals nuclear power plant in Sweden. The team assessed the plant's preparedness, organisation and programmes related to long-term operation (LTO) against IAEA safety standards.

The four-unit Ringhals plant in western Sweden (Image: Vattenfall)

Ringhals 3 - a 1062 MWe pressurised water reactor (PWR) - began operations in 1981. The original design lifetime of unit 3 and unit 4 - a 1117 MWe PWR - will expire in 2021 and 2023, respectively. Vattenfall AB, the plant operator, is planning to extend operation of both units for a total operational lifetime of 60 years each.

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.

An initial SALTO mission to Ringhals 3 was carried out in 2018. The latest mission, which began on 15 September, was requested by the Swedish Radiation Safety Authority (SSM), the country's nuclear regulatory body. The mission reviewed Ringhals' response to recommendations and suggestions made during the initial mission.

The team - comprising two experts from Belgium and two IAEA staff members - said the plant had improved ageing management of civil structures and buildings. It had also improved plant processes to manage LTO activities and plant personnel awareness of ageing management and LTO activities. A revalidation of time limited ageing analyses for mechanical components had also been completed.

However, the team noted that further work is necessary by the plant to ensure that ageing management and LTO related data are consistent and complete, and to establish a long term staffing plan for LTO.

"The team observed that the operator is preparing unit 3 for safe LTO in a timely manner," said team leader and IAEA Senior Nuclear Safety Officer Robert Krivanek. "Basing their efforts on recommendations made by the SALTO team in 2018, the plant has made significant improvements in the area of ageing management and has shown continued commitment to preparing for safe LTO. The SALTO team encourages the plant management to address the remaining findings from the 2018 SALTO mission and implement all activities for safe LTO."

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

Ringhals 1 (an 881 MWe boiling water reactor) is scheduled to shut permanently by the end of this year. Ringhals 2 (an 852 MWe BWR) closed down in December 2019 following a 2015 decision to close the reactors five years earlier than originally planned, for commercial reasons.

Researched and written by World Nuclear News