FILE PHOTO: Deputy Secretary of the U.S. Department of Energy Dan Brouillette attends a meeting of the "Energy and Climate Partnership of the Americas" (III ECPA) in Vina del Mar, Chile, September 7, 2017 REUTERS/Rodrigo Garrido Reuters

By Geert De Clercq

PARIS (Reuters) - The United States plans to extend the lifespans of existing nuclear reactors and support new technologies as it seeks to revive an industry seen as crucial to its energy security, a senior U.S. official said on Thursday.

U.S. Deputy Secretary of Energy Dan Brouillette told an International Energy Agency conference on nuclear and hydrogen in Paris that both technologies were crucial for reducing carbon emissions and boosting energy security.

The U.S. nuclear industry has been in the doldrums for years because of competition from cheap natural gas and falling costs wind and solar power costs.

Several nuclear plants have closed while a project to build two reactors in South Carolina was abandoned in 2017 with the reactors half-built and billions of dollars in sunk costs.

"We believe strongly that a strong domestic nuclear energy (industry), enabled by our existing fleet and enhanced by game-changing advanced nuclear technologies is critical to our nation's energy security, our national security, our environmental sustainability...," Brouillette said.

The U.S. department of energy (DOE) agrees with the IEA that extending the life of existing reactors is perhaps the most competitive way to produce low-carbon electricity, he said. The DOE was working to help extend the licenses for the existing fleet out to eighty years, he added.

The United States has nearly 100 nuclear reactors in operation, which produced about 20% of total electrical output in 2018, World Nuclear Association data show.

Most U.S. reactors already have seen their licenses extended to 60 years from 40 years.

LESS WASTE

In France, where state-controlled utility EDF is the world's largest nuclear operator with a fleet of 58 reactors, nuclear regulator ASN is looking into allowing reactor lifespan extensions but has not made a decision yet.

Brouillette said the U.S. industry was working on several new nuclear technologies and his department strongly supported the development of new technologies, in particular small modular reactors and micro-reactors.

"Looking forward to the next generation of nuclear power, there are nearly 50 innovative US companies that are actively working on new advanced reactor designs and we are excited about the potential that they bring to produce more energy with less waste," he said.

This year, the department has awarded over $125 million to public-private partnership projects for advanced nuclear reactor technologies.

Brouillette said the United States was also working on developing hydrogen technology, notably through its "H2@Scale" initiative, which explores the potential for large-scale production and use of hydrogen.

Government data show that the United States currently produces about 10 million metric tons of hydrogen per year, 95% of which is via energy-intensive steam reforming which takes hydrogen out of natural gas but produces carbon as waste.

Governments and companies worldwide are experimenting with producing hydrogen via electrolysis, which runs electric power through water to separate hydrogen from oxygen.

Hydrogen can be used to power cars and trucks, but so far most carmakers prefer electrical engines and batteries to hydrogen.

(This story was refiled to fix spelling of Brouillette's name on third reference)

(Reporting by Geert De Clercq; editing by Emelia Sithole-Matarise)