And the nation's nuclear weapons infra-structure is about to get smaller as well, a change that will have an impact at the Lawrence Livermore Lab.
President Bush set the stage in a meeting with Russian president Vladimir Putin in 2001.
He announced he was cutting the country's stockpile of nuclear weapons by two-thirds. Since then it's been cut by half, and with the president's announcement today the country's nuclear weapons arsenal soon will be less than a quarter of what it was at the end of the cold war.
"Because our nuclear weapons stockpile is decreasing, the United States' future deterrent cannot be based on the old Cold War model of the number of weapons, rather it must be based on the capability to respond to any national security situation, and make weapons only if necessary," said National Nuclear Security Administrator Tom D'Agostino.
Tom D'Agostino made the announcement on Tuesday.
"My vision for the future is a smaller, safer, more secure, and less expensive enterprise that leverages the scientific and technical capabilities of our workforce to meet our national security requirements," said D'Agostino.
That means the Lawrence Livermore National Laboratory will lose about 20-percent of its 8,000 person workforce in coming years. Sandia National Laboratory next door also will see reductions as testing and development functions are combined, and redundancies eliminated.
Livermore will retain some unique capabilities like testing explosives inside a laboratory.
By 2015, more than 600 buildings nationwide will be closed or no longer used in the nuclear program. That includes the Livermore lab's explosives testing facility outside Tracy.
"I think what you're going to see here is a smaller more capable laboratory ultimately. Again it has to do with the change in nature of the work, and the way we do work," said Lab Associate Director Bruce Goodwin.
Some changes are already underway.