Three potential sites near the coast, at Zarnowiec, Choczewo and Gaski, were picked from around a hundred proposed locations, PGE chief Tomasz Zadroga told reporters.

The final choice is due to be announced in around two years, when the winner of the bidding race to build the plant will also be revealed, he said.

State-controlled PGE, which is in charge of Poland's atomic power programme, is set to launch the tender process before the end of this year.

Poland, a nation of 38 million people, currently relies on its plentiful coal reserves to generate 94 percent of its electricity.

The ex-communist country, which joined the European Union in 2004, aims to construct two 3,000-megawatt reactors.

The cost of the nuclear programme is estimated at 100 billion zloty (22.1 billion euros, $29.4 billion)

Three international consortia have already expressed an interest in the project: France's EDF and Areva, US-Japanese Westinghouse Electric Company LLC, and US-Japanese GE Hitachi Nuclear Energy Americas.

The nuclear option is strategic for Poland.

One goal is to meet EU quotas for cutting the country's carbon dioxide emissions, a tough task in a coal-fired economy.

The government's energy policy also involves reducing the role of energy imports.

Poland currently relies on Russia to cover 40 percent of its gas needs, for example, while other importers supply 30 percent and its own resources account for 30 percent.

The three EU states closed down the reactors as part of their deals to join the European Union, but Brussels wants to ensure that the power plants are forever sealed off.

"It is in our citizens' interest that these reactors will be safely decommissioned and that they will never be restarted again," said EU energy commissioner Guenther Oettinger.

"This additional financial support will help the three Member States to timely progress in defueling and decommissioning of these nuclear reactors," he added.

The funds will help the three former communist states continue the safe decommissioning of the nuclear power plants known as Kozloduy (Bulgaria), Ignalina (Lithuania) and Bohunice (Slovakia).

"The Union assistance for decommissioning of nuclear power plants aims at reaching an irreversible state in the decommissioning process and eliminating the major source of radiological hazard," the commission said.

The three nations must fufill certain conditions before getting the EU funds, including fully implementing EU legislation on nuclear safety and the management of nuclear waste.

They must also create legal frameworks to raise the resources needed to cover the remaining financial needs so that they can gradually take over financial responsibility, the commission said.

The EU has committed 2.85 billion euros in financial assistance until 2013. The additional 500 million euros would come in from 2014.

Lithuania will get an extra 210 million euros until 2017, Bulgaria will have 185 million euros more until 2020 and Slovakia another 105 million euros until 2017.