May 25 (UPI) -- Current plans for maintaining and modernizing the U.S. nuclear arsenal would cost about $60 billion a year to carry out, according to estimates released this week by the Congressional Budget Office.
The office is required by law to project the 10-year costs of nuclear forces every two years, and this week released a report saying the program will cost a total of $634 billion over the next decade.
The estimates are based on fiscal year 2021 budget requests submitted by the Department of Defense and the Department of Energy.
The latest 10-year total is up 28% from the CBO's last estimate, released two years ago and estimating $494 billion over the the 2019 to 2028 period, the CBO said.
But nearly half -- 49% -- of the $140 billion increase in that total arose because the 10-year period covered by the new estimate includes two later, more expensive years of work in nuclear modernization programs.
The new estimate also reflects 10 years of economy-wide inflation, the CBO said.
The majority -- almost two-thirds -- of those costs would be incurred by the Department of Defense, with the largest costs being for ballistic missile submarines and intercontinental ballistic missiles.
The Department of Energy's nuclear costs would primarily come from nuclear weapons laboratories and supporting activities, the CBO said.
In recent years Pentagon officials have stressed the need to modernize the United States' nuclear program, with a 2018 policy calling for the expansion and modernization marking a shift from Obama-era policies seeking to reduce the size and power of the U.S. nuclear arsenal.
The emphasis on modernization has continued into President Joe Biden's administration.
Earlier this month, U.S. Strategic Command commander Navy Adm. Charles A. Richard said Russia's efforts to modernize its nuclear program are about 80% complete.
In February, deputy secretary of defense Kathleen Hicks said during confirmation hearings that modernization is key to the United States' deterrence strategy.