Kozloduy NPP plc is located 200 кm north direction from the capital of Bulgaria – Sofia and 5 km east from the town of Kozloduy, on the bank of the Danube river. 
The generation facilities and auxiliary buildings are located in an area of 1000 hectares. The bank pump station and the canals for the service water supplies are included into the infrastructure of the plant  which makes the total area of the nuclear power plant 4 471 hectares.

Kozloduy nuclear power plant is the first nuclear power plant in Bulgaria and south-eastern Europe.

The beginning of the nuclear power engineering was laid on 15 July 1966 by signing the agreement for cooperation between Bulgaria and former Soviet Union for the construction of a nuclear power plant. Following a detailed feasibility study the site on the Danube river was selected in the proximity of the town of Kozloduy.

The designs for the plant were developed by Toploelektroproekt – Moscow and Energoproekt – Sofia. The main equipment was delivered by the Soviet Union, and some separate pieces of equipment from the former German Democratic Republic , Czechoslovakia and Hungary. The ground breaking ceremony for Kozloduy NPP was held on 14 October 1969. In April 1970 the large scale construction activities for the facility, still unique for the country in the present days, started. More than one hundred thousand construction and installation workers took part in the construction.

Some completely Bulgarian projects have been implemented for the first time in the world practice in the construction of nuclear power plants. Some of these technical solutions are significant engineering achievements foreign specialists have been interested in.

The construction of the main building of Kozloduy NPP started on 6 April 1970 -240 m long, 105 m wide and 40 m high. The reactor hall, turbine hall, ventilation center and the electrical devices of the 440 MW units are inside this building. In June 1972 the first reactor arrives from the Soviet Union, and on 20 November same year it was installed into the reactor cavity.

The commissioning of Unit 1 of Kozloduy NPP in 1974 remains an important national achievement in the modern history of the country – the beginning of the nuclear power industry in Bulgaria, and also in Southeast Europe.

The construction of the plant nuclear facilities was implemented in three stages:

Stage I: 1970 - 1975 – Construction and commissioning of Units 1 and 2 with water-water reactors type WWER-440, model B-230, with two independent safety system trains. Unit 1 was commissioned in 1974, Unit 2 – in 1975.

Stage II: 1973 - 1982 – Construction and commissioning of Units 3 and 4 with water-water reactors type WWER-440, improved B-230 model, with triple redundancy of the safety systems. Unit 3 was commissioned in 1980, Unit 4 – in 1982.

In pursuance of commitments undertaken by the Republic of Bulgaria in relation to the country's accession to the European Union, the operation of Units 1 and 2 ceased at the end of 2002, and of Units 3 and 4 – at the end of 2006.

Stage III: 1980 - 1991 – Construction and commissioning of Units 5 and 6 with water-water reactors type WWER-1000, model B-320, with containment and triple redundancy of the safety systems. Unit 5 was commissioned in 1987, Unit 6 – in 1991, respectively.

Following the commitments made by Bulgaria with regard to the accession to the EU, Kozloduy NPP stopped the operation of the first four units before the expiry of their design lifetime that is 30 fuel campaigns.

 
Unit Type of reactor and capacity, MW Year of connection to the grid Closure of units Current fuel campaign Electricity generated for the period, MWh
Unit 1 WWER-440 1974 31.12.2002 23 66 675 397
Unit 2 WWER-440 1975 31.12.2002 24 68 905 334
Unit 3 WWER-440 1980 31.12.2006 22 68 703 260
Unit 4 WWER-440 1982 31.12.2006 21 66 711 966

Following Decision of the Council of Ministers’ as of 20th December 2008, Units 1 and 2 were announced as radioactive waste (RAW) management facilities and along with the personal property have been transferred to State Enterprise Radioactive Waste (SE RAW). Pursuant to the decision Kozloduy NPP shall continue operating these units in compliance with the licences obtained for E mode of operation (without electricity and/or heat generation and storage of spent nuclear fuel at the reactor spent fuel pool) up to the moment of obtaining the relevant licences by SE RAW.
On 18th October 2010 the Bulgarian Nuclear Regulatory Agency issued licences to SE RAW for the operation of Units 1 and 2 as radioactive waste management facilities which shall be decommissioned and revoked Kozloduy NPP licences for operation of the first two units in E mode of operation.

Under a Council of Ministers’ Decree as of 19th December 2012, Units 3 and 4 have been announced as radioactive waste management facilities which are subject to decommissioning. In accordance with the Decree, the necessary real and personal properties shall be transferred to the State Enterprise Radioactive Waste. Until SE RAW obtains the required licences, Kozloduy NPP shall continue operating Units 3 and 4 in compliance with the existing licences for E mode of operation.

On 25th February 2013 the Bulgarian Nuclear Regulatory Agency issued licences to SE RAW for the operation of Units 3 and 4 as radioactive waste management facilities which shall be decommissioned. In connection with the issuance of the new licences to SE RAW, the licences of Kozloduy NPP for operation of Units 3 and 4 in E mode of operation were revoked.

Plant life extension of Units 5 and 6 

The successful implementation of the national energy strategic project for Units 5 and 6 plant life extension marks the beginning of a new stage in the development of the power plant. The implementation of the project justified the nuclear facilities' capability for long-term operation – until 2047 for Unit 5, and until 2051 for Unit 6. In 2017, the Nuclear Regulatory Agency renewed the licence for operation of Unit 5 for a further 10-year period. The licence of Unit 6 for the next 10-year period was renewed in 2019. This is the maximum term of licence validity as provided for by the national legislation. After the expiry of this term the plant shall apply for further lifetime extension of the units.