A prototypical pit — a hollow sphere about the size of a bowling ball — fared well in various tests conducted by California’s Lawrence Livermore National Laboratory, establishing it as a solid model with reliable data the Los Alamos lab can use to meet its goal of developing the first usable “war reserve” pit this year.

Lab and nuclear security managers weren’t available Monday to comment because of the federal holiday. But in a recent interview with The New Mexican, lab Director Thom Mason said he was confident his teams would roll out the first war reserve pit this year that can be used in a nuclear weapon.

“This year is when we’re working to make the first certified, diamond-stamped, ‘Good Housekeeping Seal of approval’ pit,” Mason said. “We’ll make more after that.”

Lawrence Livermore’s testing determined the model pit is the most “high fidelity” plutonium bomb core the lab has fashioned in the current program, putting it on track to achieve its early pit production goals, according to the lab’s monthly newsletter.

These would not be the first war reserve pits the lab has manufactured. For a short time more than a decade ago, the lab produced 10 pits a year for Navy missiles before its plutonium facility was shut down for three years because of safety violations.

Federal officials have indicated the process had to be revamped and new equipment installed to make pits for two warheads being developed.

The new W87-1 warhead will be key in replacing the outdated Minuteman class of missile with a next-generation intercontinental ballistic missile called the Sentinel. The pits also will equip the new W93 warhead, designed by the lab to be launched from submarines.

Even with the new devices, Pentagon leaders have said they don’t aim to make the nation’s arsenal larger but will replace aging or outdated systems with newer ones to deter nuclear adversaries.

Still, with Russia, China and North Korea growing more aggressive, some White House officials have expressed willingness to expand the stockpile.

If all goes as planned, the lab will produce the first war reserve pit in the current program roughly a year later than the original target.

A timeline mandated several years ago in the National Defense Authorization Act called for the lab to produce the first pit in 2023, 10 pits in 2024, 20 pits the year after that and 30 pits by the end of 2026.

But with a nearly yearlong production delay during the pandemic and vital equipment expected to arrive years later than hoped, the Government Accountability Office estimated in a 2023 report that 2030 was a more realistic target for the lab to produce 30 pits.

It could take the lab an additional two years to obtain the backup equipment needed, in case of mechanical breakdowns, to reliably make that volume of pits, the GAO said.

Mason thinks the lab can reach the 30-pit goal a bit sooner.

“We’re shooting for 2028,” Mason said. “There is a mission driver. We need to start making pits for this Sentinel ICBM.”

In the past year, the lab made 14 “development” or prototypical pits, he said, showing it has the basic production capability to move toward 30 pits.

An anti-nuclear activist said the lab might be approaching the point of making its first war reserve pit, but he believes it has a long way to go to manufacture 30.

In response to the lab director’s timeline, Greg Mello, executive director of the Los Alamos Study Group, said it’s advantageous to the lab for Mason to be optimistic, while nuclear security managers, military leaders and congressional watchdogs like the GAO must be more realistic.

Touting the first war reserve pit about to roll off the line is a way to give a positive outlook as Congress prepares to take up the budget, Mello said.

“They’ve had a lot of bad news in term of schedule [delays],” he added. “They’re trying to make it look like they’re back on schedule.”