U.S. NRC launches investigation at Southern Georgia Vogtle 3 nuclear unit

June 21 (Reuters) - The U.S. Nuclear Regulatory Commission (NRC) said Monday it launched a special inspection at Southern Co's Vogtle nuclear power plant in Georgia to identify what led to remediation work at the third unit, which is under construction.

The NRC said its team will focus on the electrical cable raceway system, which is designed to prevent a single event from disabling redundant safety-related equipment.

Southern has said the two units under construction at Vogtle, which are billions of dollars over budget and years behind schedule, were on track to enter service next year with Unit 3 in January and Unit 4 by its regulatory-approved in service date of November 2022.

The NRC said the remediation work on the electrical cable raceway system did not cause any risk to the public since there was no fuel in the plant.

Officials at Southern were not immediately available for comment.

Vogtle 3 will be the first new reactor in the United States since 2016, when Tennessee Valley Authority finished Watts Bar 2 in Tennessee. The two units at Vogtle are the only U.S. reactors under construction.

Delays and cost overruns in building reactors could make it difficult for new nuclear to play much of a role in President Joe Biden's goal of getting all U.S. power from non-carbon-emitting sources like nuclear and renewables by 2035.

When Georgia approved the Vogtle expansion in 2009, the two 1,117-megawatt Westinghouse AP1000 reactors were expected to cost about $14 billion and enter service in 2016 and 2017.

Some analysts estimate costs have ballooned to more than $27 billion due to delays related to a nuclear accident at Japan's Fukushima plant in 2011 and the 2017 bankruptcy of Westinghouse, the project's former contractor.

Southern estimated the capital cost for its 45.7% share of the new Vogtle reactors at about $8.7 billion.

(Reporting by Scott DiSavino Editing by Marguerita Choy)