NNSA Buys New Supercomputer to Protect Nuclear Stockpile

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Worth more than $100 million, Crossroads will support predictive weapons calculations and replace an aging system.

The National Nuclear Security Administration is set to gain a new and powerful tool to advance its core, weighty mission of maintaining the nation’s nuclear stockpile: a next-generation supercomputer named Crossroads.

Selected to be sited at the Los Alamos National Laboratory’s Strategic Computing Complex and delivered in the spring of 2022, the system will be produced and powered by HPE through a $105 million contract unveiled last week. 

“Crossroads will be used to analyze and predict the performance, safety, and reliability of nuclear weapons and to certify their functionality in the absence of nuclear testing,” Los Alamos Lab’s Crossroads Project Director Jim Lujan told Nextgov via email Monday. “The ability to model the extraordinary complexity of nuclear weapons systems is an essential element of the NNSA Stockpile Stewardship Program.”

That program is a mechanism through which the NNSA and Energy Department at-large safeguard and modernize the United States’ stockpile of nuclear weapons. To do so, the agency primarily uses science-based assessments that do not involve nuclear explosives testing, as Lujan noted and the nation voluntarily ceased in the 1990s. On top of boosting that work, Crossroads will also enable future predictive weapons-related research and calculations, and support NNSA’s Life Extension Program, which aims to extend the lifespans of aging and legacy weapons. 

Critical computational modeling and simulations of atomic weapons at clear, 3D resolutions will also be generated by the system—all meant to deliberately help heighten the nuclear stockpile’s reliability and security.

The NNSA’s Advanced Simulation and Computing, or ASC, Program develops and leverages relevant, tech-centered capabilities that underpin the agency’s work in the absence of real-world testing. Crossroads will be the third Advanced Technology system within ASC. And between 2022 and 2026, the supercomputer will be tapped by the NNSA ASC tri-lab simulation community, made up of Los Alamos, Lawrence Livermore and Sandia National Laboratories.

“The primary users of ASC platforms are designers, analysts, and computational scientists,” Lujan said.

Further, as the third Advanced Technology system, Crossroads is also poised to fully replace the first system—Trinity—which is edging up on what Los Alamos lab deemed “the end of its useful lifetime.”

“As Crossroads begins to provide computational cycles to the NNSA user community, Trinity will be removed from service,” Lujan explained. “This transition period is typically 6 to 9 months.”  

While some portions of Trinity may be repurposed for deeper research at Los Alamos, Lujan noted “primarily, the system is sent to a facility for destruction.” From there, any reclaimable materials from Trinity like copper, gold, or aluminum, will be recycled.

And once delivered, Crossroads is anticipated to not only quadruple existing performance capabilities, but to also “push the cutting edge of what is possible on current systems with its 3D simulations capabilities,” and “establish a validated predictive capability for key physical phenomena,” according to the release from Los Alamos. The in-the-works system will be comprised of and powered by an architecture of multiple HPE Cray EX supercomputers that include next-generation Intel processors and HPE-made networking and software. 

Such advanced high performance computing systems are generally large in scope, but Lujan noted officials involved “do not have an approximate answer to general sizing of Crossroads at this time.”

The system was purchased through a competitive procurement process and will be funded by NNSA’s ASC program.