Harte was ratified following recommendations by a five-man selection committee who preferred the Errigal Ciaran boss ahead fancied duo Brian McIver and McKenna.
Tony Fountain, NDA chief executive, said the selection of Babcock Dounreay Partnership as the preferred bidder was a significant step in the authority's drive to attract "world-class management and innovation" to its sites.
"Offering preferred seats for sale to all Delta passengers means that we are offering different seat selection options to enable more passengers to travel in their seat of choice, " she said.