Firing Tank Operator Drew Carlson (foreground) safeguards the mouth of the 10kg spherical firing tank at LLNL’s High Explosives Applications Facility as Electronic Technician Raya Yy (background, left) and Ramrod Shawn Strickland wire a high explosive charge for an experiment. The experiment will provide data important to certifying that a refurbished nuclear warhead will work without conducting a full-scale explosive nuclear test. Photo: Julie Russell/LLNL

The nuclear arsenal of the United States had been aging since the height of the Cold War, and the fall of the Soviet Union. Military officials have ramped up a "life extension program" to refurbish the weapons stockpile, but without the testing that requires actual detonations.

The W80, a relatively small warhead at just 250 pounds, became a major part of the American nuclear force in the 1980s, and was especially valued atop air-launched cruise missiles. But it has aged along with much of the other weaponry.

Now a team from Lawrence Livermore National Laboratory has announced their work to refurbish the W80 warhead has earned an approval from the National Nuclear Security Administration.

Five milestones have been achieved, but 20 more remain to get the W80-4 into service and on alert by 2031.

Part of the plans involve finding new ways to reconstitute key components which have not been manufactured for decades, according to officials.

The main explosive charge needs to be replaced, but the original high-explosive ingredients are not available, so they must be remixed.

The use of 3-D printing is being employed to replace key parts, and to reduce costs.

But with so many alterations to the original design, the scientists and engineers need to ensure that the warheads will work, and that they will detonated when required, and not before. They have to do such checks without the benefit of actual nuclear testing. (The last U.S. nuclear test was just after the call of the U.S.S.R. in September 1992, under the codename Divider, at the Nevada test site. It was the last of 1,032 total American tests that kicked off with the historic Trinity explosion on July 16, 1945).

The Lawrence Livermore team is using its next-generation supercomputer called Sierra to do such dry testing. The advances in coding, the team said, have allowed a transition from 2-D to 3-D modeling. Hundreds of tests on the computer and at the lab’s Site 300, a 7,000-acre testing ground. 

“The LEP is driving significant innovation at LLNL,” Des Pilkington, a Weapon Physics and Design program director at the lab, said. “I’m seeing some really creative work in the options, focused on meeting established performance requirements and to minimize costs, always with an eye to what we can ultimately certify will work.

“That’s where the experimental and code innovations we’ve made under the Stockpile Stewardship Program come into play,” Pilkington, in a laboratory statement on the work, said. “They will be critical to the success of our certification plan.”

Sandia National Laboratory is the lead engineering laboratory on the project, and is working in concert with Lawrence Livermore.

The LEP has meant many more hands. In 2018 alone, 100 personnel including scientists and engineers have been added to the project, according to Livermore.

The NNSA said the air-launched cruise missile deployment of the W80 will ultimately become part of the long-range standoff (LRSO) capacity. It is envisioned as a “force multiplier” to be deployed aboard the B-52 and B-21 aircraft when complete.