Life extension considered for Kozloduy

The potential extension of the lives of the two operating reactors at Bulgaria's Kozloduy plant by up to 20 years will be examined by a consortium between Russia's Rosenergoatom and France's EDF under a recently signed contract.

The potential extension of the lives of the two operating reactors at Bulgaria's Kozloduy plant by up to 20 years will be examined by a consortium between Russia's Rosenergoatom and France's EDF under a recently signed contract.

Units 5 and 6 at the Kozloduy plant (Image: KNPP)

The contract was announced on 20 April following a meeting between Bulgarian prime minister Boyko Borisov, finance minister Simeon Dyankov and Kozloduy executive director Alexander Nikolov. Under the contract, EDF and Rosenergoatom will conduct a detailed investigation and appraisal of the resources and equipment of Kozloduy units 5 and 6, both Russian-designed VVER-1000 reactors.

The Bulgarian government said that the signing of the contract with the Rosenergoatom-EDF consortium was "the first stage of preparation" for the extended operation of the Kozloduy units. The results of the survey will be used to determine whether, and for how long, the units' operating lives could be extended. An application could then be submitted to the Bulgarian Nuclear Regulatory Agency for new operating licences.

Six Russian-supplied reactors were built at the Kozloduy plant. However, under commitments made by Bulgaria as part of its accession to the European Union, units 1 and 2 were shut down in 2002 while units 3 and 4 were shut down in 2006. All four were VVER-440 reactor models. Kozloduy 5 and 6, which began operating in 1987 and 1991, remain the country's only currently operating nuclear units, with operating licences due to expire in 2017 and 2019, respectively.

Early in 2010, a joint assessment by the Kozloduy plant and Spain's Iberdrola reported that a seventh unit at the site would be viable. The government was considering this, and a possible eighth unit, independently of plans for a new nuclear power plant at Belene. However, plans for the Belene plant were scrapped in March and earlier this month the government confirmed that the seventh Kozloduy unit will comprise what was to be Belene 1, an AES-92 plant supplied by AtomStroyExport.

Prior to the decision to build Kozloduy unit 7, energy and economy minister Delian Dobrev confirmed that the unit would not be state-funded and that a strategic investor would have to be found. A project company for the new reactor would not be likely to be formed until late in 2012 or early in 2013, he said, noting that a strategic investor would be unlikely to be found until extensive preparations - including environmental and geological studies plus licensing activities - were completed.

The two operating units at the Kozloduy plant currently supply some 35% of Bulgaria's electricity. The country may be forced to import electricity after 2019 if the operating lives of the reactors are not extended.

Researched and written
by World Nuclear News