July 19, 2021
A team of experts from the International Atomic Energy Agency (IAEA) has completed a review of the long-term operational safety of units 5 and 6 of the Kozloduy nuclear power plant in Bulgaria. The team evaluated the facility’s readiness, organization, and long-term operation (LTO) programs against IAEA safety standards.
Kozloduy Blocks 5 and 6 (Image: Kozloduy KKW)
In the Kozloduy power plant – Bulgaria’s only nuclear power plant – two pressurized water reactors with an installed capacity of approx. 1000 MWe each are in operation. Unit 5 went into commercial operation in 1987, Unit 6 in 1991. The operating licenses for the two units were extended to 2027 and 2029 respectively. Kozloduy units 1-4 have been decommissioned and are being decommissioned.
A Long Term Operational Safety Peer Review (SALTO) is a comprehensive safety review that addresses the strategy and key elements for the safe LTO of nuclear power plants. SALTO missions complement the missions of the IAEA’s Operational Safety Review Team (OSART), which are designed to review programs and activities that are essential for operational safety. SALTO peer reviews can be carried out at any time during the lifetime of a nuclear power plant, whereby according to the IAEA the most suitable point in time is within the last 10 years of the plant’s originally intended operating life. SALTO and OSART reviews are carried out at the request of the IAEA member state in which the review is to take place.
In 2016, a pre-SALTO mission was carried out in Kozloduy 5, and another in Block 6 in 2018. The last mission, which took place from July 6 to 15, was requested by the Bulgarian Nuclear Safety Authority (BNRA). . The 9-person SALTO team consisted of experts from the Czech Republic, Slovakia, Spain and the United Arab Emirates as well as three IAEA employees.
The team identified best practices to be shared with the nuclear industry around the world, including the Kozloduy Power Plant: conducts extensive annual visual inspections of civilian structures to identify aging effects at a very early stage; cooperates with technical universities and high schools to meet future staffing needs for long-term operation; and uses comprehensive information systems to monitor and assess the risk of tacit knowledge loss.
It also provided recommendations and suggestions to help the operator further improve the safe LTO. These include: fully completing the implementation of the equipment qualification program to confirm reliable safety performance; Carrying out a review of the aging management for all mechanical structures, systems and components of the plant in order to effectively cope with the aging effects; and full implementation of aging management programs to monitor the condition of low voltage cables and verify that critical cables are still reliable.
“The team has observed that the operator is implementing measures for a safe LTO,” said Gabor Petofi, team leader and nuclear safety officer of the IAEA. “Most aging management and LTO activities are already in line with IAEA safety standards. The SALTO team encourages the plant to continue improving its LTO-related performance and taking into account the results of the mission.”
“We appreciate the IAEA’s support for our facility with aging management and safe LTO,” said Nasko Mihov, CEO of Kozloduy NPP. “The results of this mission will help us further improve our safe LTO activities in line with IAEA safety standards.”
At the end of the mission, the team submitted a draft report to the plant management and the BNRA. A final report will be submitted to the plant, the BNRA and the Bulgarian government within three months.
Researched and written by World Nuclear News