SEOUL, Oct 20 (Reuters) - State-run utility Korea Electric Power Corp (KEPCO) agreed to invest $900 million in a company operating the first nuclear power plant in the United Arab Emirates, South Korea's energy ministry said on Thursday.

KEPCO expects the deal to boost its revenue by nearly $50 billion over the next 60 years, according to a statement from the ministry.

KEPCO and Emirates Nuclear Energy Corp (ENEC) signed the deal to co-invest in the company managing and operating the UAE's Barakah nuclear power plant for the next six decades, the ministry statement said.

In 2009, a KEPCO-led consortium won a contract to build the four 1,400 megawatt nuclear reactors that are being constructed at the Barakah plant to meet the UAE's surging demand for electricity.

South Korea, the world's fifth-biggest user of nuclear power, constructs and operates its reactors through KEPCO.

(Reporting By Jane Chung; Editing by Tom Hogue) ((jane.chung@thomsonreuters.com; +82 2 3704 5667; Reuters Messaging: jane.chung.thomsonreuters.com@reuters.net))