One of Los Alamos National Laboratory’s jobs just became harder with Russia suspending its participation in an arms control treaty: verifying the country’s nuclear arsenal.

Russian President Vladimir Putin announced this week his nation would no longer take part in the new Strategic Arms Reduction Treaty, or START, which calls for Russia and the U.S. to submit to inspections of their stockpiles and to cap the number of their warheads — a decision that will require the greater use of technology to gauge the arsenal, lab Director Thom Mason said in an online town hall Monday.

Although Putin intends to back out of the treaty, the lab is still tasked with finding ways to tally Russia’s nuclear weapons to see if it is complying with the treaty’s terms, Mason said.

Russia has actually granted less access to its weapons for a while, but the announcement suggests a more definite halt to inspections, he said, which will make the lab’s job more challenging.

“In the event that there are [treaty] partners who are not cooperative, we have a responsibility to try and understand what’s going on by other means,” Mason said. “We have to figure out what’s going on.”

A nuclear security manager who was on hand said the lab must keep tracking nuclear weapons as part of the non-proliferation effort.

“Non-nuclear-proliferation is still a cornerstone of our mission — it’s very critical,” said Ted Wyka, manager of the National Nuclear Security Administration’s Los Alamos field office.

The town hall was held a few days after the anniversary of Russia invading Ukraine. Putin’s decision to withdraw from START was seen by the U.S. and allies as a statement Russia was removing its nuclear restraint in response to the West aiding Ukraine.

Still, Mason didn’t talk of Russia specifically when discussing the lab’s goal of producing 30 plutonium bomb cores, or pits, per year by 2026 to modernize the U.S. arsenal, which he contends is vital to boost the nuclear deterrent.

An audience member said the U.S. was antagonizing Russia and trying to launch a new arms race and then asked Mason why the lab and the nuclear security agency planned to make more pits instead of reducing the number of weapons.

Mason said the purpose of the pits was to sustain, not expand, the arsenal. The new pits will be key in replacing the outdated Minuteman missile with a new generation of intercontinental ballistic missile called the Sentinel, he said.

Greg Mello, who heads the anti-nuclear Los Alamos Study Group, asked Mason what value the lab’s pits would be to the nation between the time it produces the first one and when Savannah River Site in South Carolina begins producing an additional 50 pits per year.

Mason said the lab is expected to make six or seven prototypical pits, which is laying the groundwork for pursuing its goal of 30 “war reserve” pits that will be used as triggers for the new warhead.

In an email after the town hall, Mello complained Mason didn’t answer his question. Mello wrote the point he was making was the pits will have no purpose because the new warhead isn’t expected to be rolled out until the 2030s.

“So the question arises: What is the nation getting for the LANL production effort that merits the investment?” Mello wrote.

Other sources in the past year have either expressed doubt about the 2026 timeline or have hinted that jumpstarting pit operations could take longer.

In a recent report, the Government Accountability Office said time and cost estimates to produce pits, including 30 per year at the lab, are severely lacking and could make it difficult for federal managers to avoid cost overruns, delays and other problems.

Ramping up pit production demands detailed scheduling, a careful accounting of costs and clear estimates of how long various tasks will take — none of which are being done by the agency in charge of nuclear weapons, the GAO said in the report.

Without this essential information, any plans to gear up the facilities to make plutonium pits is unreliable and raise questions about whether production can be accomplished by the target date, the GAO said.

Mason said systems went into place in January to address the GAO’s concerns, such as the more detailed planning and scheduling needed for pit operations to get underway by 2026.

But a management plan for the lab described how the pit production deadline is more likely to be missed because of preparatory work being delayed for 13 months during a hard-hitting stretch of the pandemic.

Also, a deputy energy secretary’s memo describes moving in some of the minimum equipment necessary for pit production by 2030, several years past the current goal.

A spokeswoman for the nuclear security agency wrote in an email an increasing number of pits can be produced each year without all the new equipment.

As the lab pursues pit production, it has expanded its workforce to almost 15,400 people. The lab hired 2,100 workers last year, 60% of them from New Mexico, Mason said.

An audience member said explosions are heard at the lab, making some people wonder whether underground nuclear tests are taking place.

Mason said explosive nuclear testing has been banned in the U.S. since 1992. The lab uses supercomputers and other means to test the effectiveness of weapons, he said.

Non-nuclear explosive devices are tested on-site, he said.

Wyka said one of the lab’s roles is stockpile stewardship, which means ensuring the current weapons are in good shape.

“We need to have weapons that work,” Wyka said.