Lawrence Livermore National Laboratory

Weapon Physics and Design Program

Physicists in the Weapon Physics and Design Program pair simulations with experiments to obtain insights into the complex physics related to nuclear weapons.

The safety, security, and effectiveness of the stockpile are at the core of the U.S. deterrence policy, and the Weapon Physics and Design (WPD) Program is responsible for ensuring its credibility without nuclear testing.

Our scientists complete this critical mission by developing and applying validated, science-based capabilities in support of the current and future U.S. nuclear stockpile through the Stockpile Stewardship Program (SSP). In performing this mission, we provide innovative technical capabilities that can be applied to current and anticipated national security problems. We bring broad theoretical, computational, and experimental expertise to all these problems, leveraging world-class research facilities at LLNL and across the National Nuclear Security Administration (NNSA) complex to deliver innovative national-security solutions.

WPD scientists have established unique expertise in stockpile science, high explosives, high-energy-density (HED) physics and material properties under extreme conditions. Our multidisciplinary teams perform applied physics research, developing new models to advance physical and computational sciences relevant to national security missions, and the nuclear stockpile in particular. We design, field, and analyze experiments to help validate these models. We also analyze data from experiments, simulations, and archived underground nuclear tests to provide options that decision makers can confidently rely upon.

Areas of weapon physics expertise and research:

  • Actinide properties
  • Astrophysics
  • Atomic physics
  • Nuclear and thermonuclear physics
  • Computational physics
  • Diagnostics
  • Fluid dynamics and turbulence
  • Hydrodynamic experiments
  • HED physics and experiments
  • Material properties under extreme conditions
  • Nuclear safety and security
  • Plasma physics
  • Radiation and particle transport
  • Reactive flows and high explosives
  • Subcritical nuclear experiments
  • Uncertainty quantification (UQ) and novel statistical methods
  • Weapon physics

World-class experimental facilities like the National Ignition Facility allow physicists to validate thermonuclear-fusion models without underground nuclear testing.

World-class facilities at LLNL and across the NNSA and Department of Energy (DOE) complex support this research. In the area of high-explosives research and development, WPD scientists make integrated use of LLNL's High Explosives Applications Facility (HEAF) and the explosives fabrication capabilities at Site 300. In support of the National Hydrodynamic Testing Program, scientists extensively use the complementary capabilities of the Dual-Axis Radiographic Hydrotest Facility (DARHT) at Los Alamos National Laboratory, LLNL’s Contained Firing Facility (CFF) at Site 300, and the U1a Complex at the Nevada National Security Site. The WPD program also conducts HED experiments at LLNL’s National Ignition Facility (NIF), Joint Actinide Shock Physics Experimental Research Facility (JASPER) at the Nevada National Security Site and other facilities around the complex. These experiments deliver validation data for multi-dimensional simulations in support of stockpile stewardship and are critical to advancing our understanding of complex physical phenomena and assessing the nuclear deterrent in the absence of nuclear testing.