An International Atomic Energy Agency (IAEA) team of experts today completed a review of long term operational safety of Unit 1 at the Angra Nuclear Power Plant (NPP) in Brazil.
The SALTO (Safety Aspects of Long Term Operation) follow-up review mission was requested by the Eletrobras Eletronuclear S.A., the operator of the plant. The mission reviewed the Angra NPP’s follow-up actions in response to recommendations and suggestions made during an IAEA Pre-SALTO mission in 2018.
During the 7-10 June mission, the SALTO team’s review focused on aspects essential to the safe Long Term Operation (LTO) of Unit 1 at Angra, which went into commercial operation in 1985. The operator of the plant, which has two reactors in operation and one under construction, is preparing a license renewal application to extend the operating lifetime of Unit 1 from 40 to 60 years.
“The team observed that the operator is preparing Unit 1 for safe LTO in a timely manner,” said team leader and IAEA Nuclear Safety Officer Martin Marchena. “Based on its efforts to address recommendations made by the SALTO team in 2018, the plant has made significant improvements in the area of ageing management. The SALTO team encourages plant management to address the remaining findings from the 2018 mission and implement all activities for safe LTO.”
The team comprising four experts – from Argentina, Slovenia, and two from Sweden – and two IAEA staff members said the plant had:
- Developed and implemented a formal policy and improved organizational arrangements for LTO.
- Completed the identification and revalidation of the Time Limited Ageing Analyses (TLAAs) used to calculate material fatigue or corrosion over time.
- Completed the development and started the implementation of a large number of Ageing Management Programmes.
The team noted that further work is necessary by the plant to ensure that:
- A comprehensive programme to confirm resistance of electrical components to harsh conditions, called equipment qualification, is fully implemented.
- Long term workforce planning for the period of LTO is developed and implemented.
Plant management expressed a determination to address the areas identified for improvement and to invite a full scope SALTO mission in 2023.
“We have a clear understanding of the contribution of IAEA missions and technical cooperation to maintain our continued focus on safe operation. We have worked together with the IAEA for the past four years carrying out several workshops and technical support missions, also sending our engineers to actively participate in review missions, working groups and technical meetings,” said João Carlos, Angra NPP Site Director. “We appreciate the IAEA’s support of our plant in managing ageing and preparation for safe LTO, and we will continue to improve our processes to further comply with IAEA safety standards.”
The team provided a draft report to the plant management and to Brazil’s regulatory authority at the end of the mission. They will have an opportunity to make factual comments on the draft. A final report will be submitted to the plant management, the Regulatory Authority and the Brazilian 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.