Ensuring stockpile reliability

Department of Nuclear Engineering

The United States has not developed new nuclear weapon designs since it ceased physical testing in 1992. Instead, purely for the sake of deterrence and national security, the nation has kept up its arsenal by refurbishing, repairing and replacing parts in some weapons and retiring many other weapons.

Keeping weapons functional is imperative to the U.S. goals of nuclear deterrence. Predictive computational modeling is an important piece of this puzzle.

“Texas A&M is unquestionably strong in predictive science and engineering in the area of particle transport, meaning neutrons, photons and charged particles,” says Dr. Marvin Adams.

He says this strength stems from collaboration within the multidisciplinary predictive computational modeling group. The research group includes Adams; nuclear engineering professors Dr. Jim Morel and Dr. Jean Ragusa; Dr. Lawrence Rauchwerger and Dr. Nancy Amato, professors in the Department of Computer Science and Engineering; Dr. Bani Mallick, Susan M. Arseven ’75 Chair in Data Science and Computational Statistics; Dr. Jean-Luc Guermond, professor and Mobil Chair in Computational Science; and Dr. Raytcho Lazarov and Dr. Bojan Popov, professors in the Department of Mathematics.

“The expertise we’ve developed here at Texas A&M is also part of what made us an attractive partner in the competition for the contract to manage and operate the Los Alamos National Laboratory (LANL), another DOE facility.”
– Dr. Marvin Adams, Associate Director, Institute for National Security and Cybersecurity Education and Research; Deputy Director, Center for Exascale Radiation Transport; HTRI Professor

The researchers develop predictive science and engineering methods that help national laboratory experts calculate the effects of time on nuclear weapons and their probabilities of success as they age. The more time passes from when the devices were originally tested (prior to 1992), the more difficult calculations become. Materials degrade over time and devices change from their tested configurations through refurbishments  and repairs. Eventually, each type of nuclear weapon in the U.S. arsenal will have to be refurbished or replaced, so every variable must be carefully calculated.

“Anybody can calculate an answer, but calculating how accurate your answer is and predicting uncertainties is extremely difficult,” says Adams.

Partners in National Security

Adams and his fellow researchers are working on several projects in this realm. Each is sponsored by the U.S. Department of Energy’s (DOE) National Nuclear Security Administration (NNSA) or one of its laboratories.

The team is currently working on an $11 million project through the Center for Exascale Radiation Transport.

“An important phenomenon in nuclear weapons is thermal radiation transfer,” says Adams. “We figure out how to develop and test predictive methods for thermal radiation transfer by using neutron transport as a surrogate. We design complicated neutron-transport experiments, predict the results, predict how close our answers should be to reality, execute the experiments and then compare the experimental results to our predictions.”

Lawrence Livermore National Lab (LLNL), one of the DOE facilities, is sponsoring two of the team’s current projects. Through the $1.4 million “Computational R&D in Support of Stockpile Stewardship” project and the $1.5 million “Collaborative R&D in Support of LLNL Missions” project, the team is developing advanced computational methods and new computational results that support the nation’s nuclear deterrence and other national security missions. This is the third set of three-year projects from LLNL that Adams and Morel have co-led. The projects grew out of Texas A&M’s role as an Affiliate of Lawrence Livermore National Security, LLC, the organization that manages LLNL for the NNSA.

“The expertise we’ve developed here at Texas A&M is also part of what made us an attractive partner in the competition for the contract to manage and operate the Los Alamos National Laboratory (LANL), another DOE facility,” says Adams. The Texas A&M University System, University of California and the Battelle Memorial Institute, united by their shared commitment to national service, formed Triad National Security, LLC, which was awarded the LANL contract in June 2018. The Triad team assumed management of LANL on November 1.

PROJECTS