ALBUQUERQUE, New Mexico (Reuters) - Defense Secretary Chuck Hagel said on Wednesday the United States had always supported a strong nuclear deterrent and would continue to do so, even as it braces for a nuclear forces overhaul that analysts say could cost $1 trillion over 30 years.
"To modernize your nuclear weapons stockpile and assure that they continue to stay secure and safe, it takes money, it takes resources," Hagel said after touring Sandia National Laboratories and Kirtland Air Force Base, two facilities involved in maintaining the weapons.
The U.S. defense chief said upgrading U.S. nuclear warheads and the submarines, bombers and missiles that deliver them would require setting priorities and minding the budget, but he added the country "has always been willing to make that investment and I think it will continue to make it."
The visit was part of a two-day trip to bases supporting U.S. nuclear forces. Hagel travels on Thursday to F.E. Warren Air Force Base in Cheyenne, Wyoming, where he will see intercontinental ballistic missile silos and talk to troops in a nuclear mission that has been troubled by morale problems.
Major General Michael Carey was fired as head of the 450-weapon U.S. intercontinental ballistic missile force in October for getting drunk and carousing with Russian women while leading a government delegation to Moscow for talks on nuclear security.
Hagel acknowledged the morale problems in the unit and said he planned to underscore the importance of the ICBM mission and thank the troops for their service.
"They do feel unappreciated many times," he said. "They're stuck out in areas where not a lot of attention is paid."
Hagel's visit to the nuclear-related facilities comes as the administration is pushing ahead with ambitious plans to upgrade nuclear systems by modernizing weapons and building new submarines, missiles and bombers to deliver them.
The Congressional Budget Office estimated in late December the plans would cost $355 billion over the next decade. The Center for Nonproliferation Studies calculated in a study on Tuesday that the upgrade would cost $1 trillion over 30 years.
"These are going to cost much more than people appreciate they are going to cost," said Jon Wolfsthal, the deputy director of the center in Monterey, California. "Annually we're going to be spending upwards of $33 billion ... once we get to year 11, 12 and onward."
The administration plans to modernize its 1970s-era nuclear bombs - some of which still use vacuum tubes that date to the 1960s - and upgrade them with current electronic components and tail kit guidance systems to make them more accurate.
At the same time, the Pentagon is planning to build a dozen new ballistic missile submarines, a new fleet of long-range nuclear bombers and new intercontinental ballistic missiles to replace the current delivery systems, all of which are nearing the end of their useful life.
Critics of the administration's plans say the spending is excessive given President Barack Obama's announcement last year that a nuclear posture review had concluded the United States could reduce the size of its arsenal by about a third to between 1,000 and 1,500 deployed atomic weapons.
Under the New START treaty Obama negotiated with Russia, the two former Cold War rivals are committed to reduce their deployed strategic nuclear weapons to 1,550 per side by 2018.
"In a constrained budget environment, and in a time in which the president has already determined that the United States can reduce our deployed strategic arsenal by a third, ... we don't believe the taxpayer should be asked to build a new triad that's the same size, the same firepower as the triad that we no longer need," said Daryl Kimball, head of the Arms Control Association.
Supporters of the plans say the spending is a small proportion of the overall Defense Department base budget, which has been running at more than $500 billion annually, and they note that maintaining a credible deterrent is necessary to fulfill treaty obligations in Europe and Asia.
Clark Murdock, a nuclear weapons expert at the Center for Strategic and International Studies think tank, said Russia had been modernizing the legs of its own triad and had become more reliant upon nuclear arms as its conventional forces weakened.
"I don't want the Russians thinking they have a superior nuclear force," he said, adding it was also important to maintain nuclear forces superior to those of China to fulfill U.S. treaty obligations to Japan, South Korea and others.
"This is an uncertain time, particularly in the Asian sphere, particularly with China getting more and more aggressive and assertive about its territorial claims within the region," Murdock said. "Under those kind of circumstances, that's not a time when you take a way the overarching security architecture that's anchored right now on the U.S. nuclear umbrella."
Editing by Eric Walsh