The Savannah River Site will shift to minimum mission essential operations after an employee at the DoE nuclear weapons and cleanup site tested positive for COVID-19, the agency said Monday.

The worker, who DoE did not identify, could be the first confirmed positive case at a DoE defense-nuclear site. Savannah River includes nuclear weapons work handled by DoE’s National Nuclear Security Administration (NNSA). 

“The transition to minimum mission-critical activities is being specifically tailored to each facility at SRS and must be conducted in an efficient and safe manner,” the DoE wrote in a press release Monday afternoon.

The NNSA processes tritium at the Savannah River Site. The radioactive hydrogen isotope increases the explosive power of nuclear weapons. Most deployed nuclear weapons must have their tritium reservoirs periodically refilled because the gas decays naturally over a period of several years. Savannah River fills fresh tritium reservoirs that are installed in weapons at the Pantex Plant in Amarillo, Texas.

The NNSA is also preparing to convert a partially built plutonium recycling plant at Savannah River into a factory that can, by 2030, annually produce 50 plutonium pits – fissile nuclear weapon cores – for planned W87-1 warheads. The W87-1 will tip the Ground Based Strategic Deterrent: the future silo-based intercontinental ballistic missile that will replace Minuteman III missiles beginning in 2030 or so.

An NNSA spokesperson did not immediately return a request for comment at deadline Monday for Defense Daily. Administratively, the Savannah River Site is complicated. The Department of Energy’s Office of Environmental Management operates the site, and runs a massive, Cold War nuclear-waste cleanup mission there. The NNSA funds its national security work at the site through the Environmental Management office’s site-management contractor, Fluor [FLR]-led Savannah River Nuclear Solutions.

Meanwhile, as they did last week, NNSA nuclear weapons production facilities are still calling in all of their workforce.

A phone message posted Sunday to the Kansas City National Security Campus’ phone directory said the plant, which makes the non-nuclear parts of nuclear weapons, was deemed “an essential government function” and that “operations are not impacted by the recently announced 30-day stay at home order for Kansas City are residents.”

Kansas City announced its first confirmed cases of COVID-19 last week.

Likewise, the main phone switchboard and website for the Pantex Plant in Amarillo, Texas, the sole U.S. assembly and maintenance hub for nuclear weapons, said workers are to report for their shifts as normal.

As of Friday, a few Pantex employees who returned recently from international travel were in quarantine. None of them reported any definitive exposure to COVID-19, a spokesperson for plant operator Consolidated Nuclear Security said Friday. The company also manages the Y-12 National Security Complex in Oak Ridge, Tenn., and said the nation’s weapon-uranium center was still open for business, going into the weekend. Y-12 also has an undisclosed number of quarantines of personnel returning from international travel, the Consolidated Nuclear Security Spokesperson said.

There were more than 40,000 COVID-19 cases in the U.S. as of Monday morning, according to a tracker maintained by Johns Hopkins University in Baltimore. There were more than 570 deaths attributed to the disease at deadline Monday. The confirmed U.S. death toll for the disease has now increased more than tenfold in less than a month.

Meanwhile, the Lawrence Livermore National Laboratory in California planned by the end of the day to complete its transition to minimum safe operations, restricting on-site work to those involved with “identified mission-critical activities.” The lab is in charge of the W80-4 and W87-1 warhead modernization projects, which will head into the production pipeline once another two weapons, the B61-12 nuclear gravity bomb and W88 Alt-370 submarine launched ballistic missile, roll out. The transition at the production sites is supposed to start by the middle of this decade.

As Livermore rolls into a near-lockdown, the Los Alamos National Laboratory in New Mexico is also tightening its response to COVID-19. According to guidelines from Director Thomas Mason, any lab employees returning from travel outside New Mexico must now self-quarantine for 14 days, whether symptomatic or not.

Weeks after the World Health Organization declared COVID-19 a pandemic, the NNSA is beginning to consider the expense the disease will impose on a civilian nuclear weapons complex that is rapidly reordering day-to-day operations.

The Sandia National Laboratories, the multi-site lab network headquartered in Albuquerque, N.M., that focuses on nuclear weapons engineering, provided some clarity about the central bureaucracy’s efforts in a web post last week.

“Due to state, local and national work restriction orders, NNSA [the National Nuclear Security Administration] has asked us to track expenses related to COVID-19,” the Sandia National Laboratories in New Mexico said in a post dated Thursday.

About a third of the labs’ workforce of 14,000 started teleworking last week as part of the national effort to eliminate most inessential gathering of people in all walks of life. Among the mundane, but important, adjustments during the transition is how to account for time spent working at home.

Sandia will cope, on top of everything else, with redoing its employees’ timesheets from the week starting March 13, according to the Albuquerque-based labs’ website. The codes workers use to account for COVID-19-related expenses have changed since telework started, and could change again.