An International Atomic Energy Agency (IAEA) team of experts completed a review of long term operational safety at Unit 1 of the Angra Nuclear Power Plant (NPP) in Brazil.
The Safety Aspects of Long Term Operation (SALTO) review mission was requested by the Eletronuclear S.A, the public entity that owns and operates Angra NPP. Two IAEA pre-SALTO missions in 2013 and 2018, followed by a pre-SALTO follow-up in 2022, were previously conducted to review the long term safety of the unit.
Eletronuclear submitted a license renewal application to the Brazilian Nuclear Regulatory Authority (CNEN) in 2019 to extend the operating lifetime of the 640 Megawatt electric (MWe) Unit 1 from 40 to 60 years. The plant, located 150 kilometres west of Rio de Janeiro, went into commercial operation in 1985 and its current operating licence expires in December of 2024. The two other units of Angra NPP, the 1350 MWe Unit 2, which started its commercial operation in 2001, and the 1405 Mwe Unit 3, which is under construction, were not part of the review.
During the ten-day mission from 4 to 13 June, the team reviewed the plant’s preparedness, organization and programmes for safe long term operation (LTO). The mission was conducted by a twelve-person team comprising experts from Argentina, Bulgaria, Finland, Japan, Republic of Korea, the Netherlands, Slovakia, and the United States, as well as two IAEA staff members. The team held discussions with staff from Angra NPP and conducted plant walkdowns during the review.
“The team noted the progress in measures taken by the operator to ensure the safe LTO of the plant. The professionalism, openness and receptiveness for improvements to meet and move beyond the IAEA safety standards in operation are commendable,” said Gabor Petofi, team leader and IAEA Senior Nuclear Safety Officer. He added that “most of the ageing management and LTO activities are already in alignment with IAEA Safety Standards. We encourage the plant to address the review findings and proceed with the implementation of all remaining activities for safe LTO.”
The team identified several good practices and good performances at the Angra NPP that will be shared with the nuclear industry globally, including:
- The confirmation process to regularly evaluate and improve ageing management programmes.
- The software tool developed to determine opportunistic inspections of components.
- The use of artificial intelligence to determine the qualified life of plant equipment.
The team also provided recommendations to further enhance the preparations for safe LTO, including for the plant to consider:
- Consistently addressing and implementing all ageing management programme attributes for civil structures.
- Improving the process of temporary design modifications for LTO.
- Implementing a comprehensive equipment qualification programme.
The plant management expressed determination to address the areas identified for improvement and to invite a SALTO follow-up mission in 2026.
“Eletronuclar is strongly committed to satisfy all regulatory requirements and implement all possible improvements that can be derived from international best practices and IAEA Safety Standards” said Abelardo da Cruz Viera, Angra Unit 1 plant manager. “The SALTO findings will help us ensure a safe and reliable completion of LTO activities and improve performance for the next cycle of operation of the plant”.
The team provided its draft report to the plant management and CNEN at the end of the mission. The plant management and CNEN will have an opportunity to make factual comments on the draft. The final report will be submitted to the plant management, CNEN and the Brazilian Government within three months.
This mission was supported by the IAEA’s Technical Cooperation Programme which assists Member States in the use of nuclear technology for sustainable socioeconomic development.
Background
Information on SALTO missions can be found here.
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.
