An International Atomic Energy Agency (IAEA) team of experts today completed a review of long term operational safety of the Oskarshamn Nuclear Power Plant (NPP) Unit 3 in Sweden.
The Safety Aspects of Long Term Operation (SALTO) review mission was requested by the plant's operator, OKG Aktiebolag. Oskarshamn Unit 3, situated roughly 300 kilometers south of Stockholm, was put into commercial operation in 1985 with a design life of 40 years. It is equipped with one boiling water reactor and has a net electrical output of 1400 MW(e). The plant operator is preparing to extend the operating lifetime to 60 years. Two other units at the power station are in permanent shutdown. Nuclear power accounts for more than a quarter of Sweden's electricity production.
During the ten-day mission from 1 to 10 October, the team reviewed the plant's preparedness, organization and programmes for safe long term operation (LTO), which built upon an initial IAEA pre-SALTO mission held at the plant in 2022. The mission was conducted by an eleven-person team consisting of experts from Argentina, Belgium, Brazil, Pakistan, Spain, and the United States, as well as three observers from Hungary and the Netherlands, and two IAEA staff members. The team met and discussed topics in depth with staff from the Oskarshamn NPP and conducted site walkdowns during the review.
"The team observed that OKG is preparing for safe long term operation and the plant staff are cooperative, professional, and open to suggestions for improvement," said team leader and IAEA Nuclear Safety Officer Bryce Lehman. "We encourage the plant to address the review findings and implement the remaining activities for safe long term operation as planned."
The team identified good performances that will be shared with the nuclear industry globally, including:
- Reconstitution of design documentation in cooperation with the original equipment manufacturer (OEM) and securing access to the OEM archives for the period of long term operation.
- Development of a user-friendly database that shows each user their assigned maintenance activities.
- Regular meetings of experts from different plant departments to share experience, including international experience, and to discuss improvements to the plant for long term operation.
The team also provided recommendations and suggestions to further improve safe LTO, the most significant are the following:
- The plant should fully justify LTO through a periodic safety review, or alternative process.
- The plant should fully establish a comprehensive programme to identify ageing management activities for long term operation.
- The plant should properly implement a comprehensive process to identify components requiring ageing management (a scoping process).
The plant management expressed a determination to maintain the level of preparedness for safe LTO and further cooperate with the IAEA in this field.
"We appreciate the IAEA's support to our plant in ageing management and preparation for safe LTO," said Johan Lundberg, President of OKG. "It is very important for us to get an external view on our business. The competencies and experience of the IAEA team enable it to effectively identify our areas for improvements. The results of this mission will help us to improve our activities for safe LTO and to further align them with IAEA safety standards."
The team provided a draft report to the plant management and to the Swedish Radiation Safety Authority (SSM), the country's nuclear regulatory authority, at the end of the mission. The plant management and SSM will have an opportunity to make factual comments on the draft. A final report will be submitted to the plant management, SSM and the Swedish Government within three months.
Background
General information about SALTO missions can be found on the IAEA Website. A SALTO peer review is a comprehensive safety review addressing strategy and key elements for the safe long term operation of nuclear power plants. They complement OSART missions, which are designed as a review of programmes and activities essential to operational safety. Neither SALTO nor OSART reviews are regulatory inspections, nor are they design reviews or substitutes for an exhaustive assessment of a plant's overall safety status.
LTO of nuclear power plants is defined as operation beyond an established time frame determined by the license term, the original plant design, relevant standards, or national regulations. As stated in IAEA safety standards, to maintain a plant's fitness for service, consideration should be given to life limiting processes and features of systems, structures, and components (SSC), as well as to reasonably practicable safety upgrades to enhance the safety of the plant to a level approaching that of modern plants.
