The Point Lepreau nuclear generating station returned to commercial operation on Friday, more than three years behind schedule and $1 billion over its original budget.

Gaëtan Thomas, the president and chief executive officer of NB Power, said the refurbished nuclear reactor will provide 25 to 30 years of power.

"It's a foundational piece of our domestic energy supply and our export sales, and provides rate stability and the financial flexibility to now begin reducing debt," Thomas said in a statement.

"We can now accelerate our investment in other priorities such as our new strategic direction around helping customers reduce their energy use."

The president said NB Power will continue to test and monitor the reactor in the next few weeks to "ensure that all aspects of the facility are working as intended and responding appropriately as part of the electricity system."

Point Lepreau, Atlantic Canada's only nuclear reactor, has been out of service since March 2008.

The reactor was originally scheduled to come back online in September 2009, but that date was moved to December 2009, January 2011 and then February 2012 as various problems cropped up.

When the project started in 2008, it was the first time Atomic Energy of Canada tried to refurbish a Candu-6 reactor.

The reactor ran into problems when dozens of calandria tubes flunked air tightness tests after being fused with special inserts designed to hold them in place.

AECL started a similar refurbishment project on a Candu-6 reactor in Korea.

The Wolsong project started a full year after Point Lepreau but finished in 2011 and that plant has been producing power for nearly 15 months.

The New Brunswick government is attempting to get the federal government to cover the cost overruns.

Prime Minister Stephen Harper has said the federal government would only pay its contractual obligations.

The delay in restarting the nuclear reactor has not only impacted the New Brunswick government.

The P.E.I. cabinet approved another $5.5 million for Maritime Electric to cover off costs associated with buying replacement energy while the Point Lepreau reactor continued to be refurbished.

The P.E.I. government has paid $48.5 million for replacement power during the refurbishment.

Maritime Electric has contract that guarantees it a percentage of power generated by Point Lepreau.

The power corporation is now starting a plan to pay down the debt incurred during the refurbishment.

Ed Barrett, the chairman of NB Power, said the utility will use the power generated by the reactor to export to power-hungry markets.

"Our plan is to pay down debt by $1 billion over the next decade and the completion of this project allows us to now begin this pursuit in earnest," Barrett said in a statement.