Unit 5 of Bulgaria’s Kozloduy Nuclear Power Plant has resumed electricity generation following the completion of its scheduled annual maintenance outage. The 1,000 MW reactor was successfully reconnected to the national grid on Monday, 15 June, after receiving authorization from the Nuclear Regulatory Agency, which reviewed the results of the maintenance works and approved the unit’s return to service.
The outage began on 9 May and included a broad scope of inspection, repair, and modernization activities aimed at ensuring the continued safe and efficient operation of the unit. Alongside routine maintenance procedures, engineers also carried out upgrades related to the long-term operational sustainability of the reactor.
A key element of the shutdown was the loading of fresh nuclear fuel supplied by Westinghouse. This marks the third consecutive operating cycle in which RWFA fuel assemblies have been used, as Bulgaria continues its efforts to diversify fuel sources for its VVER-1000 reactors. The diversification program, initiated in 2024, represents a significant step in strengthening fuel supply security.
Bulgaria has become the first European Union member state to introduce an alternative fuel source for this type of reactor, reducing dependence on a single supplier. Plant officials note that the initiative has attracted strong attention from the broader European nuclear industry, where concerns over fuel security and supply chain resilience have grown in recent years.
