ELLSWORTH AIR FORCE BASE, S.D. (AP) — The U.S. military on Wednesday chose Ellsworth Air Force Base as the first training site for new B-21 bombers that are capable of launching thermonuclear weapons.

U.S. Sens. John Thune and Mike Rounds hailed the announcement as an economic boon for the area, saying a flurry of construction will be necessary to accommodate the planes and the hundreds of new airmen and their families who will be coming to the base. The senators also say Ellsworth will need to construct hangars, training areas, and facilities to store the thermonuclear weapons.

“Obviously that has a ripple effect throughout the entire economy,” Thune said.

The Air Force says the planes are expected to arrive by the middle of next year. Whiteman Air Force Base in Missouri and Dyess Air Force Base in Texas will also get B-21 bombers later as they become available.

The Air Force said in a press release that Ellsworth was the first choice “because it provides sufficient space and existing facilities necessary to accommodate simultaneous missions at the lowest costs.”

The announcement also marks a reversal of fate for Ellsworth Air Force Base. The Rapid City Journal reports that in 2005 it was briefly added to a Pentagon list of military bases that should be closed or relocated. But the area took steps to make sure the base remained open.

“This is a major, major event for the community,” Rounds said.

Rounds said at least 100 of the B-21 planes are being built. He said the number of planes Ellsworth will get and when they will arrive is classified.