An International Atomic Energy Agency (IAEA) team of experts has completed a review of long term operational safety at the Oskarshamn Nuclear Power Plant (NPP) Unit 3 in Sweden.
The Pre-SALTO (Safety Aspects of Long Term Operation) review mission was requested by the plant's operator, Oskarshamns Kraftgrupp (OKG) Aktiebolag. Oskarshamn Unit 3, situated roughly 300 kilometers south of the capital Stockholm, was put into commercial operation in 1985 with a design life of 40 years. Oskarshamn Unit 3 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.
The SALTO team assessed the strategy and key elements for the safe long term operation of the nuclear power plant based on IAEA safety standards. During the ten day mission that ended on 8 September, the team reviewed the plant's preparedness, organization and programmes for safe long term operation (LTO).
The mission was conducted by a nine person team comprising experts from Argentina, Armenia, Brazil, Canada, France and the United Kingdom, as well as two IAEA staff members. The team met and discussed topics in depth with staff from the Oskarshamn NPP.
"The team observed that OKG Aktiebolag is implementing preparations for safe LTO in a timely manner and the staff at the plant are professional, open and receptive to suggestions for improvement," said team leader and IAEA Nuclear Safety Officer Martin Marchena. "Some ageing management and LTO activities already meet IAEA safety standards. We encourage the plant to address the review findings and implement all remaining activities for safe LTO as planned."
"We appreciate the IAEA's support to our plant in ageing management and preparation for safe LTO," said Johan Lundberg, Managing Director of OKG. "It's very important for us to get an external view of our business. The competencies and experience of the IAEA team enable it to effectively identify our areas for improvement. 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 identified good practices and good performances that will be shared with the nuclear industry globally, including:
- The plant has developed and fully implemented a comprehensive system for the management of spare parts' obsolescence.
- The plant has developed and implemented performance monitoring of the cooling circuits for fouling and flow resistance.
- The plant has developed and implemented a machine learning software to monitor turbine performance.
The team also provided recommendations to further enhance the preparations for LTO safety:
- The plant should ensure adequate resource planning to support the LTO programme.
- The plant should fully define the organizational arrangements for LTO.
- The plant should implement an appropriate knowledge management process.
The plant management expressed a determination to address the areas identified for improvement.
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 LTO 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 licence 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, as well as to reasonably practicable upgrades to enhance the safety of the plant to a level approaching that of modern plants.
