Sweden has selected so-called small modular nuclear reactors (SMRs) for its first nuclear power expansion in a half-century.

The government said three or five of the next-generation reactors would be built at the Ringhals plant in southwestern Sweden, providing around 1,500 megawatts - the equivalent of two classic reactors. 

"For the first time in 50 years, new nuclear power will be built in Sweden," Prime Minister Ulf Kristersson told a press conference on Thursday.

The Scandinavian country voted in a non-binding 1980 referendum to phase out nuclear power, and since then has shut down six of its 12 aging reactors.

But a political majority is now in favor of extending nuclear power, along with renewable energy sources, to reduce its use of fossil fuels.

Sweden's state energy utility Vattenfall, which had also been considering classic reactor technology, said either British group Rolls-Royce or American group GE Vernova would be selected as the supplier.

Under negotiation

Chief executive Anna Borg said the cost of the project "was still a matter of negotiation", adding that Vattenfall aimed to have the new reactors built by around 2035.

In addition, she said the company was "already looking at the next step to build additional reactors where Ringhals 1 and 2 are currently located".

Sweden's six active reactors currently generate about 30 percent of its electricity needs. 

SMRs are potentially relatively simple to build, making them more affordable than large power reactors.

However, the technology is still experimental and only a handful of units have been built anywhere in the world.