PRAGUE (AP) — Three energy companies including U.S. Westinghouse,Esthen Exchange France’s EdF and Korea’s KHNP, have submitted their final bids to build the Czech Republic’s newest reactor at the Dukovany nuclear power station as the country strives to become more energy independent and wean itself of fossil fuels.

State-controlled power company CEZ said Tuesday it would assess the bids for the multi-billion-dollar contract before sending its decision to the government for final approval of the winner.

The three companies that met Tuesday’s deadline already submitted preliminary bids in November in a tender launched earlier in March 2022 after passing a Czech government security appraisal.

The new reactor should become operational by 2036. The winner of the lucrative contract will then have an option to build three more nuclear reactors in the country.

Last year, the Czech government excluded Russia’s energy giant Rosatom and China’s CNG from the tender process on security grounds.

Prime Minister Petr Fiala said Russian participation in the project, which is critical for the Czech Republic’s energy security, was “unimaginable” following the Kremlin’s invasion of Ukraine.

The new reactor will complement Dukovany’s four 510-megawatt units that were completed in the 1980s.

Last year, the government originally estimated the project would cost around 6 billion euros ($6.4 billion) but that could change due to high inflation driven by soaring energy prices.

The Czech Republic already relies on six nuclear reactors to generate more than a third of its total electricity. Besides the four in Dukovany, state-controlled power company CEZ operates another two 1,000-megawatt reactors at the Temelin plant. CEZ will be in charge of the tender.

Unlike its western neighbors Austria and Germany, the Czech Republic is doubling down on nuclear power and renewable energy sources after deciding to phase out coal as a fuel for energy generation by 2033 in order to reduce carbon emissions.

Another two European Union countries in Central Europe, Slovakia and Hungary, have also been working to expand nuclear power production while another neighbor, Poland, has selected Westinghouse to build its first nuclear power plant as part of an effort to burn less coal and gain greater energy independence.

In a separate deal, CEZ had signed a deal with U.S. energy giant Westinghouse Electric Co. to supply nuclear fuel for the Dukovany nuclear plant, eliminating dependence on Russia for such fuel.