An International Atomic Energy Agency (IAEA) Safety Aspects of Long Term Operation (SALTO) team of experts has completed a review of long term operational safety at Bulgaria’s Kozloduy NPP.

The follow-up mission was requested by the Bulgarian government to review Kozloduy’s response to recommendations and suggestions made during an earlier SALTO mission in 2021.

The review focused on aspects essential to the safe long term operation (LTO) of units 5&6 at Kozloduy, which began commercial operation in 1987 and 1991. Kozloduy NPP comprises two VVER-1000 pressurised-water reactor units. The operation licences of the units have been extended until 2027 for unit 5 and until 2029 for unit 6. Units 1-4 (VVER-440s) were closed by 2007 as a condition for Bulgaria’s accession to the European Union 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 comprised three experts from Armenia, the Netherlands, and Slovakia as well as three IAEA staff members. They concluded that 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 still needed 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.

Image: Kozloduy nuclear power plant (courtesy of Kozloduy NPP)