Late delivery of new underground testing lab might not affect design of Navy warhead

WASHINGTON — A three-year slip for a new x-ray imager will not necessarily result in a bigger, more massive W93 nuclear warhead, senior officials from Los Alamos National Laboratory said here Thursday.

That was a slight change in tune compared with an appraisal one of these people made last year.

For the last three years, the National Nuclear Security Administration (NNSA) said Los Alamos will make the first copy of the W93 submarine-launched ballistic missile warhead by 2036 or so, according to the agency’s three most recent unclassified Stockpile Stewardship and Management Plans. 

But in the last year, the agency has acknowledged that the new x-ray imager Scorpius, needed for future underground, subcritical tests at the Nevada National Security Site to evaluate weapons plutonium and components, will arrive in 2030 instead of 2027. 

Asked whether the instrument’s late arrival could tie the hands of weapon designers at Los Alamos, the director of the lab said “no” and the head of the lab’s weapon program said “not obvious[ly].”

“I think we’re okay for the [W]93,” Thomas Mason, director of the Los Alamos National Laboratory, said here Wednesday on the sidelines of the Exchange Monitor’s annual Nuclear Deterrence Summit. “It’s an important tool to get a handle on plutonium aging so … it has more to do with the legacy stockpile.”

W93 will be the first nuclear warhead designed from an almost-clean sheet since the end of the Cold War in the early 1990s; its nuclear explosive package will be based on a design already tested at full yield, but other components and its Mk7 reentry vehicle will be new.

Robert Webster, deputy director for weapons at the Los Alamos National Laboratory, said that Scorpius “would help answer” some questions that weapon designers might have about a new nuclear weapon, like how streamlined and lightweight they could make the weapon and still virtually guarantee that it will explode only when required to.

Having data from Scorpius would “in principle” … change probably things like range and stuff somewhat,” Webster said here Thursday on the summit sidelines. “We haven’t gotten far enough to actually know whether we need it yet.”

But specifically in W93’s case, “it’s not obvious to me” that making the weapon without feedback from Scorpius would foreclose any designs weaponeers at Los Alamos have in mind.

Meanwhile, there will be a W93 customer requirements review in March, said Laura McGill, deputy laboratories director for nuclear deterrence and chief technology officer at the Sandia National Laboratories in Albuquerque, N.M.