This is the second story in a series about Sentinel, the Air Force’s nuclear missile modernization project. Other stories touch on the challenges in the surrounding communities near Sentinel construction and with the Air Force’s budget issues.
At Los Alamos National Laboratory in New Mexico, where the U.S. built its first nuclear bomb, work on a key component of the next generation of nuclear missiles is already underway.
Workers have begun laying the groundwork for the first production later this year of plutonium “pits” — hollow spheres the size of a half grapefruit, made from the rare chemical element. They fit inside a warhead and create a nuclear explosion when compressed by explosives.
These pits are crucial: As a source of nuclear fuel, they will transform the Air Force’s new, modernized nuclear missiles, called Sentinel, into weapons of mass destruction. Sentinel is scheduled to be fielded in the Western rural U.S. in the 2030s, though that is likely to be delayed.
The pit work will first unfold at the nation’s only fully operational plutonium pit production facility, the Plutonium Facility at Technical Area 55, in a building known as PF-4 at Los Alamos.
Overseeing the production is the Department of Energy’s National Nuclear Security Administration (NNSA), which is pushing to get Los Alamos whirring to life this year to start making plutonium pits, with the hopes of eventually producing 30 per year at the site. The agency also plans to open a brand-new plutonium pit production plant in South Carolina, known as the Savannah River site, to meet an ultimate target goal of 80 pits a year.
But the NNSA hasn’t done large-scale pit production since the early 1990s, creating unease about restarting the process after decades of inactivity. And the agency is plagued by schedule delays, workforce challenges and budget concerns.
Sébastien Philippe, a research scientist at Princeton University who has closely tracked the Sentinel project, said the NNSA is struggling to meet its goals and raised concerns about the lack of a specific cost estimate for pit production.
“At this point, the deadline keeps moving, and the cost keeps growing,” he said.
The pit production is part of a U.S. scramble to modernize its entire triad after delaying such efforts for years due to the war on terrorism. The total modernizing effort is expected to exceed more than a trillion dollars.
Washington will replace its aging Minuteman III Intercontinental Ballistic Missiles and build new submarines and bomber planes capable of carrying nuclear weapons, with the latest 10-year projection cost putting the modernization effort at $750 billion.
As part of the overall modernization effort, the NNSA plays a key role in ensuring the warheads remain viable for all three legs of the triad. It must recycle its old plutonium and make fresh shells.
The first 800 pits produced by NNSA are expected for the W87-1, a new warhead for the Sentinel based on a similar design used for newer Minuteman warheads. The NNSA has a separate budget from the Air Force, which is struggling with rising costs for the project.
Along with the challenges of starting up a process that has been dormant for years, the race to swap Minuteman III, a nearly 80,000 pound missile, for the even heavier Sentinel missile is pressing the NNSA, given the 2030 timeline to start deployment of the new systems.
“The United States has not really been producing [pits] since the end of the Cold War … and the plan is to ramp that up again,” said Connor Murray, a research analyst at the Center for Arms Control and Non-Proliferation. “There are still a number of unanswered questions.”
Complex, costly, concerning
The NNSA pit production effort has been flagged for several years by a government watchdog group, the Government Accountability Office (GAO). The GAO in a 2020 report said history has “cast doubt on NNSA’s ability to produce the required number of plutonium weapon cores on schedule.”
“We found NNSA’s plans for re-establishing pit production do not follow best practices and run the risk of cost increases and delays,” GAO said in an updated report last year. “The re-establishment of pit production capabilities is one of the most complex and potentially costly efforts presently operated by NNSA.”
The NNSA budget for pit production proposed in Congress for the next fiscal year is around $3 billion. The overall NNSA budget is expected to be boosted by 8 percent to $24 billion, based on congressional budget documents.
Sen. Elizabeth Warren (D-Mass.), a member of the Senate Armed Services Committee, grilled NNSA Administrator Jill Hruby in a 2022 hearing over budget and schedule concerns.
“I remain concerned about the costs and the risks in the pit production program, which is already far behind schedule and far over budget,” Warren told Hruby. “The American people, truly, they want to spend what it takes to keep us safe. But when you can’t answer basic questions about these programs, it does not inspire much confidence.”
In last year’s National Defense Authorization Act, which was signed into law in December, lawmakers inserted several amendments due to concern about NNSA’s work.
Congress noted that reports have flagged the management and oversight of the plutonium modernization program with “serious deficiencies,” and required the NNSA to develop a master schedule and a life-cycle cost estimate.
Lawmakers wrote that the NNSA was “not optimized to meet mission requirements.”
The NNSA said it was tackling challenges found by the GAO report. The agency acknowledged it was not on schedule to produce the required pits by 2030 but added its first pit production unit would be ready by the end of the year.
“NNSA is on track to establish a reliable, enduring pit production capability,” the NNSA said in an emailed response. “NNSA is developing the capability to manufacture plutonium pits at this rate as close to 2030 as economically and technically feasible.”
The NNSA also said it was still updating total cost estimates for the pit production program. The agency said it would have a better sense of total acquisition costs by April, although that update would still have “significant uncertainties.”
An improved cost estimate with fewer uncertainties is expected by mid-2026.
NNSA facing workforce challenges, lawsuit
The first plutonium pits were created at the Los Alamos site for the Trinity test, which saw the world’s first detonation of a nuclear bomb in the desert of New Mexico. Pits were also made there for the bomb dropped over Nagasaki in Japan in World War II.
But Los Alamos has only done limited pit production since the end of World War II, with most of the work afterward taking place at the Rocky Flats Plant in Colorado, a facility that was making thousands of pits per year during the Cold War.
The U.S. stockpile hit a high of 31,225 nuclear weapons, each with a plutonium pit inside, in 1967. The stockpile was gradually reduced over the years after Washington made treaties with Russia, and today the number of deployed and in-storage nuclear weapons in the U.S. is closer to 5,400.
After Rocky Flats closed in the 1990s, Los Alamos remains the only pit production site in the country, though many of the tens of thousands of pits made by the U.S. during the Cold War are still in storage.
In the new effort, workers are not creating new plutonium. Instead, they will recycle plutonium from old pits and make them anew.
A plant near Amarillo, Texas, will first remove old plutonium pits from weapons and send them to Los Alamos, where the pit is disassembled and then remade into a new pit. A new warhead will fit over the pit back in Texas.
At Los Alamos, 2,500 people are expected to work on pit production. Some new construction is required to meet demand at the site, including constructing four additional buildings between 2024 and 2027.
The decades of inactivity on pit production have sparked concerns that the necessary skill and workforce just aren’t available.
Frank von Hippel, a prominent nuclear policy scientist, said the ability to hire adequate workers is top of mind for the NNSA. He compared the thinking to “a panic.”
“Other countries, Russia, China, are producing pits and we’re not,” he said. “Maybe we don’t know how.”
The NNSA said Los Alamos has done some pit production research, and between 2007 and 2011, the facility replaced the pits in 31 warheads.
“A wealth of experience and expertise is available at Los Alamos and across the national laboratories,” the agency said. “Specialized training and education of its workforce remains a high priority for NNSA, especially as it plans to ramp up plutonium pit production in the future.”
With the NNSA restarting pit production after so long, others are concerned about the potential for contamination and leakage from the hazardous practice.
Rocky Flats looms large over the debate. In 1957 and 1969, fires broke out at the facility and nearly created an environmental catastrophe on par with the meltdown in Ukraine’s Chernobyl plant.
The site was also known to have leaked barrels of radioactive waste into nearby fields. The FBI and the Environmental Protection Agency raided Rocky Flats in 1989 over environmental concerns.
The facility stopped production in 1992 and officially shut down in 1994. The Department of Energy took 10 years to clean up the area, which was designated as a hazardous waste site.
And Los Alamos itself has shut down in the past, from 2013-16, over safety concerns at PF-4.
The shaky history has spurred concerns in the communities around Los Alamos, where the “downwinders” — those who were affected by the winds carrying radioactivity after the Trinity test — have long kept a critical eye on NNSA operations.
As part of the new pit production, remaining plutonium after conversion to a new pit will be stored as waste. That waste will be sent to a disposal plant in Carlsbad, N.M.
Los Alamos said the facility has upgraded fire suppression systems and checked nuclear containers to ensure safety in case of an accident. Additionally, plutonium pits are handled inside of sealed compartments, which technicians insert gloves into to prevent harmful exposure.
But Jay Coghlan, executive director of Nuclear Watch New Mexico, wasn’t convinced the safety measures were sufficient.
“Los Alamos has a very checkered nuclear safety track record,” he said, and “production always causes more contamination and more radioactive waste.”
Coghlan sued the NNSA in 2021 for violating the National Environmental Policy Act (NEPA), which requires an environmental review and public input for government projects. He said the NNSA has not conducted a robust town hall or environmental review on the pit production.
“That is not just a paper document. It requires public hearings. It requires NNSA to essentially make its case,” he said. “It requires NNSA to respond to public comment.”
The NNSA said it has completed all necessary NEPA activities, “which included more public participation than required.”
“We are confident in the results,” the agency said. It also said protections have improved from Rocky Flats and that it has extensive hazard protections for workers.
“There is no question that worker protection, safety standards, procedures, and oversight have greatly improved since the days of the Rocky Flats site,” officials said.
Questions linger over Savannah River
At the Savannah River site in South Carolina, the NNSA will have to start up a facility that has never produced plutonium pits.
Savannah River helped produce plutonium and other materials during the Cold War, but it never made the pits themselves. Like Rocky Flats, it closed in 1992, but reopened as a facility processing plutonium for reactors, a site that was eventually closed too.
The NNSA wants the site back online to meet its target goal of 80 pits per year, and is planning to train workers at Los Alamos.
With Los Alamos aiming for 30 pits a year, the agency seeks to repurpose the old facility at Savannah River to produce 50 additional pits per year to meet the target goal of 80 annually.
The new Savannah site is only half-designed and is estimated to finish construction sometime between 2032 and 2035 — missing the goal of the Air Force, which wants to field its 400 Sentinel missiles in 2030.
At the same time, the budget for the site to complete construction has ballooned from about $3 billion in 2017 to an estimated cost of $11 billion.
Von Hippel, the nuclear policy scientist, and Curtis Asplund, an assistant professor in the department of physics and astronomy at San José State University, said it would be better to focus on small-scale pit production at Los Alamos first.
“Trying to build a second pit production facility at the Savannah River Site in a building designed for another purpose while simultaneously re-equipping Los Alamos’s plutonium facility and crowding it with hundreds of trainees for both facilities is a prescription for a fiasco,” they wrote in an opinion last year.
“The NNSA will have a better chance for success if it focuses on getting one well-designed pit production line up and working well.”
The NNSA argues that Los Alamos will reach a 50-year design life in 2030 and that Savannah is needed to diversify the work.
“The two-site solution was chosen in 2018 after consideration of many factors, including the need for resiliency,” officials said in an email.
The NNSA said it was committed to providing updated cost and schedule estimates for the Savannah site by April and that it would also provide “quarterly construction updates that include the latest estimates for costs and schedules.”
With the challenges facing the NNSA, critics question if the pits are even needed, given the tens of thousands made during the Cold War period. The pits used today are about 40 years old, and while around 100 years is considered the end of a pit’s life, that’s a best guess.
The scientific advisory group JASON found changes in plutonium over time but reported in 2019 that studies on plutonium aging has “not been sufficiently prioritized over the past decade.”
Thom Mason, director of the Los Alamos lab, has said they “don’t have an immediate concern with aging” and the current pits have been “very robust.”
“We don’t have the predictive ability to say with certainty that our current, 40-year-old pits will be good until any particular date,” he said in a 2021 report by Los Alamos. “It’s sort of glass half full, glass half empty. We can’t prove that they will fail, but we also can’t prove that they will work.”
The NNSA said estimating the aging of pits is “difficult” but explained it was working with JASON to “conduct an updated assessment of plutonium pit aging not later than 2030.”
The agency argued that “newly manufactured pits are needed to improve warhead safety and security.”
“Plutonium is unstable and radioactively decays over time. Experiments have demonstrated that the material properties of plutonium pits change over time in ways that affect the performance of nuclear weapons,” the NNSA said.
“It is difficult to quantify how much the properties of a plutonium pit will change over time, and even more difficult to quantify how much those changes will affect weapon performance under all relevant conditions.”
Lawrence Livermore National Laboratory is the NNSA design agency for the nuclear explosive package for the new Sentinel warhead and works with Los Alamos pit production.
Juliana Hsu, the program manager for the warhead program at Lawrence Livermore, said most pits were made between 1952 and 1989, making most of them between 30 and 60 years old.
While the lifetime of pits depends on the design of the system, “It’s not the right thing to do to keep reusing old components in future systems,” she added. “Most older pits may not be appropriate for modern designs that we need to be able to keep up with our peer adversaries as our adversaries are also developing new systems.”