Democratic Bulgaria's first ever referendum, on whether to build a second nuclear power plant, looked set to fail Sunday because of insufficient turnout, exit polls showed.
Between 19.5 and 20.3 percent of voters cast ballots, a third of the 60-percent level needed for the EU member's first referendum since communism to be valid, the exit polls showed.
The result, although invalid, went against the government's decision to ditch last March plans to build a new nuclear power plant at Belene in northern Bulgaria.
Between 60.0 and 60.3 percent backed the Socialists, who support a revival of Belene and who had initiated the referendum. Between 39.7 and 40.0 percent voted "no".
The central electoral committee has yet to announce its official turnout figures. Final results are expected within the next three days.
If final official participation is confirmed to be over 20 percent, with over half of the voters in the "yes" camp, parliament will have to review the issue within three months.
Lawmakers will not be obliged to revive the deal, however.
Prime Minister Boris Borisov already said the government did not have money to build Belene "whatever the referendum result."
Instead, the government envisages extending the operational life of the two reactors at Bulgaria's Kozloduy plant and possibly adding another reactor at the site.