The Nuclear Power Plant in Cernavodă (Romanian: Centrala Nucleară de la Cernavodă) is the only nuclear power plant in Romania. It produces around 20% of the country's electricity. It uses CANDU reactor technology from AECL, using heavy water produced at Drobeta-Turnu Severin as its neutron moderator and as its coolant agent. The Danube water is not used for cooling of the active zone (nuclear fuel).

By using nuclear power, Romania is able to reduce its greenhouse gas emissions by over 10 million tonnes each year. CNE-INVEST is responsible for the preservation of Units 3–5.

During the Communist era, the idea of building a nuclear power plant arose. A first plan to build the power plant on the Olt river with Soviet technology was rejected by Nicolae Ceaușescu as he wanted the country to remain independent of the USSR and avoid potential "energy blackmail". Before the project started, a team of Romanian researchers traveled to the United States in 1968 for an American Nuclear Society conference where they requested approval for the transfer of Canadian nuclear technology to Romania. The United States Atomic Energy Commission subsequently approved this request in 1970, and the feasibility study for the future power plant was completed in 1976.

The project began in 1978, the same year as the military nuclear program, and the power plant was designed in Canada by Atomic Energy of Canada Limited in the 1980s. The initial plan was to build four units, and schedule their startup from 1985 onward. A fifth unit was subsequently planned on the direct orders of Communist leader Nicolae Ceaușescu during a visit to the site. The plant's originally planned units 1 to 4 are in a neat line and unit 5 is offset due to the local geology. Units 1 and 2 are currently operational. Three more partially completed CANDU reactors exist on the same site, part of a project discontinued at the fall of the Ceaușescu regime, their work being halted since 1 December 1990.

Unit 1, a CANDU 6-type, was finished in 1996 and produces 706.5 MW of electricity. Its scheduled startup, however, would have been circa 1985, had it not been for the economic factors at the time.

It was commissioned and began operating at full power in 1996 and has had record capacity factors of 90 percent since 2005.

In 2019 planning was progressing for a modernisation scheme for 30 years of plant life, to be carried out by Korea Hydro & Nuclear Power who have experience of CANDU modernisation at Wolseong. A refurbishment outage is expected from December 2026 and December 2028. Optimization work was decided in 2022 to be done by Candu Energy Inc.

A consortium of AECL and Ansaldo Nucleare of Italy, along with the Nuclearelectrica (SNN) SA, Romania's nuclear public utility, was contracted in 2003 to manage the construction of the partially completed Unit 2 power plant and to commission it into service.

Four years later, Unit 2, another CANDU 6-reactor, achieved criticality on 6 May 2007 and was connected to the national grid on 7 August. It began operating at full capacity on 12 September 2007, also producing 705,6 MW.

Unit 2 was officially commissioned on October 5, 2007. With 2 units active, CNE-Cernavoda Station became the third largest power producer in the country.

Units 3 and 4 were expected to be CANDU 6 reactors with a similar design to Unit 2 and will each have a capacity of ~700 MW. The project was estimated to take up to six years after the contracts are signed.

A 2006 feasibility study carried out by Deloitte and Touche determined that the most economically viable scenario was to build the two reactors at the same time, with the cost estimated at €2.3 billion.

On 20 November 2008, Nuclearelectrica, ArcelorMittal, ČEZ, GDF Suez, Enel, Iberdrola and RWE agreed to set up a joint company dedicated to the completion, commissioning and operation of Units 3 and 4. The company named Energonuclear was registered in March 2009.

20 January 2011, GDF Suez, Iberdrola and RWE pulled out of the project, following ČEZ which had already left in 2010, citing "Economic and market-related uncertainties surrounding this project, related for the most part to the present financial crisis, are not reconcilable now with the capital requirements of a new nuclear power project". That left Nuclearelectrica with large majority share in the project, prompting a search for other investors. In November 2013, China General Nuclear Power Corp. (CGN) signed an agreement to invest in the project at an undisclosed level. Shortly thereafter, ArcelorMittal and Enel announced plans to sell their stakes.

In 2016 the Romanian government gave support for the creation of a joint venture led by China General Nuclear (CGN) to progress the project. In November 2015 Nuclearelectrica and CGN signed a memorandum of understanding regarding the construction, operation and decommissioning of Cernavoda 3 and 4. However, in January 2020 the government under Ludovic Orban decided to abandon the proposal.

In October 2020, new plans were launched with cooperation from the US, Canada and France. The two reactors are expected to become functional in 2030 and 2031, respectively.

In November 2024, an engineering, procurement, and construction (EPC) contract to finish Units 3 and 4 was signed by a joint venture consisting of Fluor, AtkinsRéalis, Ansaldo Nucleare and Sargent & Lundy Energie. The contract was signed at the 2024 United Nations Climate Change Conference (COP29) and is worth €3.2 billion.

There are currently no plans to complete Unit 5 at this time. However, the possibility of finishing construction remains.

In June 2024, construction work began on the tritium removal facility at Cernavodă. The facility, built by Nuclearelectrica with Korea Hydro & Nuclear Power, will use technology developed in Romania and will become the third such facility in the world and the first in Europe. The project was started in 2023 after the contract worth $200 million was signed.

• In the summer of 2003, the sole operating reactor at the time had to be closed, because of the lack of cooling water. It was brought back online after roughly 2–3 months.
• On 8 Apr 2009, the second reactor of the Romania's Cernavodă NPP was shut down due to a malfunction which led to electrical outages.
• On 30 May 2009, Unit 1 of the Romania's Cernavodă NPP was shut down following a water pipe crack. The Cernavodă NPP's second unit was undergoing an overhaul, so it was not producing any electricity.
• On 16 January 2010, the first unit was shut down due to steam leakage.

• Energy in Romania
• Nuclear power in Romania
• Atucha Nuclear Power Plant - another heavy water reactor whose construction was completed after decades of interruption

• Official site Archived 2011-09-05 at the Wayback Machine (in Romanian)
• CBC clip discussing the construction of the plant