ROME —Italians began voting Sunday in a referendum on whether to indefinitely shelve government plans to revive the country's nuclear-energy plans, following the nuclear crisis at Japan 's Fukushima Daiichi plant.

The vote on whether to resurrect nuclear energy in Italy, which was halted in 1987, is part of a packet of referenda that also asks Italians to vote on the privatization of the country's water utilities and on whether to reject a controversial law approved by the conservative government last year that exempts top...