Polling stations in Bulgaria opened Sunday for a referendum on building a second nuclear power plant, seen as a political popularity contest ahead of elections in July. The EU member\'s first referendum since the end of communism in 1989 sees 6.9 million voters eligible to vote for or against the new plant at Belene in the north of the country. First conceived in 1987, the project was frozen and revived several times before being abandoned by the current right-wing government of Prime Minister Boyko Borisov last March. The referendum was initiated by the opposition Socialists after the state-owned Russian firm set to build it, Atomstroyexport, filed a one-billion-euro ($1.3-billion) compensation claim. The poll is largely expected to be invalidated because of an insufficient voter turnout. In order to be valid the referendum has to attract participation from as many people as those who voted in the last general elections, or 4.35 million voters, and over half of them must support the \"yes\" or \"no\" stance. Eve-of-ballot surveys suggested that a mere 1.6 to 2.1 million people would vote, with 60-62 percent of those backing Belene compared with 38-40 percent against. Nevertheless, both the government and opposition are keen to chalk up a victory, even if it is only symbolic. Polling stations opened at 6:00 am (0400 GMT) and will close at 7:00 pm (1700 GMT), with the first exit poll results expected shortly afterwards.