The reactor, one of the four being built at the $20-billion Barakah plant west of Abu Dhabi by a consortium led by Korea Electric Power Corp. (KEPCO), had been due to begin operating this year.
But UAE nuclear regulators are still reviewing the operating licence application which was submitted in March 2015, Emirates Nuclear Energy Corp. (ENEC) announced.
The delay aims "to ensure sufficient time for international assessments and adherence to nuclear industry safety standards, as well as a reinforcement of operational proficiency for plant personnel," it said.
It said the new schedule reflects "lessons learned" from problems at South Korea's New Gori No. 3 reactor. The Barakah plant is based on the same technology.
ENEC said the project, which will be operated by a joint venture with KEPCO, is now 79-percent complete.
When fully operational the four reactors are expected to provide up to a quarter of the UAE's electricity.
There was no immediate comment from UAE nuclear regulators. The IAEA declined to comment.
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