The head of the joint Navy-Department of Energy naval reactors program insisted construction on the first Columbia-class ballistic submarine will begin in 2021, but warned that “there will be problems,” and that the Navy will “have to work hard to get her on patrol in 2031.”

“We need Columbia boats,” Adm. James Caldwell, head of naval reactors, said in a speech at the 2018 Naval Submarine League’s annual symposium and industry update in Arlington, Va. “We have deferred this investment for as long as we possibly can. We cannot defer it any longer.”

Caldwell was the opening speaker for the two-day event, which drew a mix of industry, government, active and former military personnel, and press.

General Dynamics [GD] Electric Boat, Gronton, Connecticut, is the prime contractor for the Columbia-class ballistic-missile submarine, working on design and development under a roughly $5-billion contract awarded last year by the Navy. 

The Navy estimates it will cost about $130 billion to build 12 Columbia-class submarines to replace the 14 Ohio-class ballistic missile submarines active today. Ballistic missile submarines are designed to be an undetectable, globe-canvassing force that guarantee an unstoppable nuclear counterstrike to any target on the Earth’s surface. Columbia subs will carry 16 carry Trident II-D5 missiles tipped with W76 nuclear warheads maintained by the Department of Energy. Ohio subs carry 24.

Politically, support for the submarine leg of the U.S. nuclear Triad — submarines, silo-based intercontinental ballistic missiles, and nuclear-armed bomber aircraft — has been strong during the first two Republican-controlled years of the Trump administration. However, Democrats retook control of the U.S. House of Representatives on Tuesday, setting the stage for debates in a divided Congress over the ongoing U.S. nuclear modernization program, which includes Columbia.

Meanwhile, in a brief question and answer session in which Caldwell fielded queries submitted anonymously on notecards, the head of naval reactors brushed off concerns that a declining commercial nuclear-power industry might drive up Columbia’s costs, or the costs of future reactor cores.

“If there are less vendors in our base, then our overhead’s going to go up and that’s going to be a challenge for us,” Caldwell said.

However, naval reactors, particularly their cores, are “vastly different” from commercial reactors, Caldwell said. Naval reactors, for example, burn highly-enriched uranium: bomb-grade material that is more energetically dense than the low-enriched uranium U.S. commercial reactors use. That means the Navy is not buying equipment on the margins of larger commercial contracts that allow an of economy of scale.

“In terms of the nuclear vendor base, I think we’re in good shape,” Caldwell said. “We have really developed … the ability to monitor, support, predict and work with a small vendor base. In some cases, it’s a sole-source vendor.”

BWX Technologies [BWXT], Lynchburg, Virginia, is the Navy’s sole supplier of naval reactors.

When General Dynamics starts building Columbia subs in its Gronton, Connecticut, shipyards in 2021, the Navy and its contractors will be churning out three submarines a year: one Columbia-class missile submarine and two Virginia-class attack subs. From 2008 through 2011, the Navy was building only one submarine, a Virginia-class, a year. The service ramped up to two Virginia-class subs a year at Congress’ behest during then-President Obama’s first term. General Dynamics started building Virginia-class subs in the late 1990s.