Kozloduy NPP previously operated four older reactors of the VVER-440/230 design, but under a 1993 agreement between the European Commission and the Bulgarian government, Units 1 and 2 were taken off-line at the beginning of 2004.
An unpublished 1995 report by the United States Department of Energy had supposedly listed those units among the world's "ten most dangerous reactors".
On 21 October 2010, licenses for the shutdown reactors were transferred to Bulgaria state radioactive waste enterprise DP RAO, signaling the formal beginning of decommissioning work.

Throughout the 1990s and early 2000s Units 3 and 4, originally licensed for operation until 2011 and 2013, respectively, underwent substantial safety improvements and, after rigorous inspections, received positive reviews from the IAEA in 2002, and from the World Association of Nuclear Operators (WANO) in the following year, concluding that "no technical reasons exist for the early closure of units 3 & 4".
Backed by these findings, the government had hoped to convince the European Commission to allow a postponement of the agreed pre-accession shutdown; from a legal and political standpoint, however, this proved untenable.
Units 3 and 4 were taken out of operation in the final hours of 2006, immediately prior to the country's accession to the European Union.

82 metric tons of its spent fuel were sent to a repository in Zheleznogorsk, Krasnoyarsk Krai during 2001 and 2002.
In 2008, officials at the power plant announced their intention to use CONSTOR storage casks for this purpose.

Prior to the shutdown of units 3 and 4, Kozloduy NPP produced 44% of Bulgaria's electricity supply; as of March 2006, Bulgaria exported about 14% of its electricity production.
Kozloduy NPP previously operated four older reactors of the VVER-440/230 design, but under a 1993 agreement between the European Commission and the Bulgarian government, Units 1 and 2 were taken off-line at the beginning of 2004. An unpublished 1995 report by the United States Department of Energy had supposedly listed those units among the world's "ten most dangerous reactors". On 21 October 2010, licenses for the shutdown reactors were transferred to Bulgaria state radioactive waste enterprise DP RAO, signaling the formal beginning of decommissioning work.
Throughout the 1990s and early 2000s Units 3 and 4, originally licensed for operation until 2011 and 2013, respectively, underwent substantial safety improvements and, after rigorous inspections, received positive reviews from the IAEA in 2002, and from the World Association of Nuclear Operators (WANO) in the following year, concluding that "no technical reasons exist for the early closure of units 3 & 4". Backed by these findings, the government had hoped to convince the European Commission to allow a postponement of the agreed pre-accession shutdown; from a legal and political standpoint, however, this proved untenable. Units 3 and 4 were taken out of operation in the final hours of 2006, immediately prior to the country's accession to the European Union.
82 metric tons of its spent fuel were sent to a repository in Zheleznogorsk, Krasnoyarsk Krai during 2001 and 2002. In 2008, officials at the power plant announced their intention to use CONSTOR storage casks for this purpose.
Prior to the shutdown of units 3 and 4, Kozloduy NPP produced 44% of Bulgaria's electricity supply; as of March 2006, Bulgaria exported about 14% of its electricity production.
Kozloduy Nuclear Power Plant