A decadelong effort to refurbish thousands of aging nuclear warheads has run into serious technical problems that have forced delays and exacerbated concerns about the Energy Department's ability to maintain the nation's strategic deterrent.
The program involves a type of warhead known as the W76, which is used on the Navy's Trident missile system and makes up more than half of the deployed warheads in the U.S. stockpile.
The refurbishment program is aimed at replacing thousands of parts that have aged since the bombs left the factory 20 and 30 years ago.
The $200-million-a-year program is a cornerstone of America's nuclear deterrent strategy, and the Energy Department has been under growing pressure from the military and Congress to meet tough deadlines to get the weapons ready.
In February, the department's National Nuclear Security Administration announced that the "first refurbished W76 nuclear warhead had been accepted into the U.S. nuclear weapons stockpile by the Navy."
But no delivery was ever made. The warhead is in pieces inside a production cell at the Energy Department's Pantex plant in Amarillo, Texas, according to an engineer at the facility.
The delay in retrofitting the warheads appears to validate long-standing concerns about an erosion of technical expertise at the Energy Department, as Cold War-era scientists and engineers retire and take with them detailed knowledge about the bombs.
Although the nation's nuclear weapons are functional and reliable, the W76 issue represents one of the most serious setbacks in the nuclear weapons program at least since the end of the Cold War and raises questions about the future, several experts told The Times.
"I wouldn't say the deterrent has been affected at all," said Philip Coyle, a former deputy director at the Lawrence Livermore National Laboratory and former assistant secretary of Defense. "It is, however, a reminder that expertise about nuclear weapons is a precious thing and needs to be maintained."
He said the W76 problem underscored concerns experts have long raised about maintaining nuclear weapons decades after they were designed, manufactured and tested.
As the nation reduces the size of its stockpile under treaty agreements with Russia, he said, the reliability of the remaining weapons becomes more important.
