CAPE TOWN (Reuters) - South Africa's Koeberg nuclear power plant will be allowed to run one of its two units for another 20 years, the country's nuclear regulator NNR said on Monday, after deliberations by the regulator's board.

The 40-year operating licence of Unit 1 of the plant outside Cape Town was due to expire this month, but state-owned power utility Eskom applied for a 20-year extension to operations as part of efforts to end crippling power shortages.

Some environmental activists opposed the application, citing heightened safety concerns.

"The NNR board of directors approved the granting of the application for Koeberg nuclear power station Unit 1 to operate for 20 years until the 21st of July 2044 subject to ... safety improvements identified as part of the third periodic safety review," NNR Chief Executive Ditebogo Kgomo said.

The regulator is still assessing Eskom's application to extend the life of Koeberg Unit 2 by another 20 years, but that unit's licence is valid until November 2025.

Koeberg, currently the only operational nuclear power station on the African continent, has a capacity of around 1,900 megawatts, accounting for roughly 5% of the electricity generated by Eskom.

(Reporting by Wendell Roelf; Additional reporting by Tannur Anders; Editing by Alexander Winning)