The National Nuclear Security Administration (NNSA) has not missed a single milestone in the six months since the first case of COVID-19 was recorded on U.S. shores and four months since the World Health Organization declared the disease a pandemic, the agency’s leader said Monday.

“Faced with the unprecedented challenges created by the COVID-19 pandemic, [the NNSA] quickly adapted in order to fulfill our national security missions,” Administrator Lisa Gordon-Hagerty said during the virtual annual meeting of the Institute of Nuclear Materials Management (INMM). “As a result of pulling together as one NNSA, I am proud to say that we have not missed any deliverables or milestones during the COVID-19 pandemic.”

Gordon-Hagerty was one of two keynote speakers during the morning plenary, appearing screen-by-screen with Ambassador Gustavo Zlauvinen of Argentina, the president-designate of the 10th Review Conference of the Nuclear Nonproliferation Treaty.

In a question-and-answer session, Gordon-Hagerty pushed back against safeguards watchdog and INMM member Edwin Lyman, who asked how the nuclear weapons agency will keep its protective forces in fighting shape, now that NNSA has suspended force-on-force training — essentially, scrimmages for site security personnel that simulate terrorist threats and other incursions into sites that hold special nuclear material.

“What we’re doing is we’re just delaying the exercise parts, only to ensure and to maintain a modicum of health and safety for our workforce,” Gordon-Hagerty told Lyman. “It does no one any good to potentially expose our workforce, our security workforce or our safety workforce unnecessarily during the pandemic, so that then we have hot spots of COVID.”

The NNSA’s weapons production operations have continued throughout the pandemic at the Kansas City National Security Complex in Missouri, the Pantex Plant in Amarillo, Texas, the Savannah River Site in Aiken, S.C., and the Y-12 National Security Complex in Oak Ridge, Tenn.

That is despite confirming 137 cases of COVID-19 within the NNSA complex since the start of the outbreak. The agency hasn’t released the numbers of associated quarantines among its workforce, nor described the COVID-related loss of productivity in terms more specific than what Gordon-Hagerty used again on Monday. She also touted the NNSA’s streak of continuing deliverables and milestone-making in May, during a meeting of the Secretary of Energy Advisory Board.

Also in May, though, Rep. Mac Thornberry (R-Texas), the outgoing House Armed Services leader whose congressional district includes Pantex, said some delays to NNSA weapons programs are “inevitable.”

As cases climb nationwide, some of NNSA’s major programmatic milestones remain ahead.

For example, the agency is not slated until December to finish its Critical Decision 1 review — a project management milestone that formalizes a design preference and sets costs ranges — for converting Savannah River’s terminated Mixed Oxide Fuel Fabrication Facility into a factory to cast at least 50 plutonium nuclear-warhead cores per year.

In February, only a month after the first confirmed case of COVID-19 in the U.S., contractor Savannah River Nuclear Solutions said it would be ready to start the review by the end of June.

Likewise, the Pantex Plant, in the midst of the worst outbreak in the NNSA production complex, has been chugging along between major modernization programs for most of the pandemic. There won’t be a crush of work on a big program until after the first production unit of the W88 Alt-370 submarine-launched ballistic-missile warhead is done, some time in fiscal 2021.

“Given where Pantex is at, kind of between some production runs, that’s actually not a bad place to be,” Drew Walter, who is performing the duties of deputy assistant secretary of defense for nuclear matters at the Pentagon, said in late May during a webcast discussion on nuclear modernization.