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IAEA Concludes Long Term Operation Safety Review at Bulgaria’s Kozloduy Nuclear Power Plant

Kozloduy, Bulgaria

An International Atomic Energy Agency (IAEA) team of experts today completed a review of long term operational safety of the Kozloduy Nuclear Power Plant (NPP) in Bulgaria.

The Safety Aspects of Long Term Operation (SALTO) follow-up review mission was requested by the country’s government. The mission reviewed the Kozloduy NPP’s response to recommendations and suggestions made during an IAEA SALTO mission in 2021.

During the 13-15 June mission, the SALTO team’s review focused on aspects essential to the safe Long Term Operation (LTO) of unit five and six at Kozloduy, which went into commercial operation in 1987 and 1991 respectively. Kozloduy NPP is Bulgaria’s only nuclear power plant and the two pressurized-water reactor units provide an installed power of approximately 1000 MWe each. The operation licenses of the two units have been extended until 2027 for unit five and until 2029 for unit six. Units one to four were all shut down by 2007 and are in the course of decommissioning.

“The team observed that the operator has completed all major actions to safely operate the reactors in the LTO period,” said team leader and IAEA Senior Nuclear Safety Officer Gabor Petofi. “Based on its efforts on recommendations made by the SALTO team in 2021, the plant has made significant improvements in the area of ageing management. The team found that these activities are consistent with IAEA Safety Standards for safe long-term operation.”

The team – comprising three experts from Armenia, the Netherlands, and Slovakia, and three IAEA staff members – said the plant had:

  • Finished the ageing management review for mechanical components and cables.
  • Completed the requalification programme for safety related electrical and cables components.
  • Analysed the situation related to human resources for the intended period of LTO and extended the human resources policy and strategy accordingly.

The team noted that further work is necessary by the plant to ensure that:

  • The new ageing management programmes developed for mechanical components and cables are properly implemented.

Plant management expressed a determination to maintain the level of preparedness for safe LTO and further cooperate with the IAEA in this field.

“For us, this is the final step of the IAEA’s supporting service to ensure safe operation of our reactors in the LTO period. The IAEA SALTO missions and technical cooperation helped to improve our continued focus on safe operation,” said Andrey Krasnocharov, Deputy CEO of Kozloduy NPP. “We have worked together with the IAEA for the past eight years carrying out four missions and several technical discussions. 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,” he added.

The team provided a draft report to the plant management and to Bulgaria’s Nuclear Regulatory Agency 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 Nuclear Regulatory Agency and the Bulgarian Government within three months.


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.


Last update: 19 Jun 2023

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