Lawrence Livermore National Laboratory

Simulation of the grain structure of a
beryllium–copper tamper for a fusion
ignition capsule in the presence of
a NIF laser energy drive.
The LLNL code projects that develop and improve the weapons simulation tools, the physics, the engineering, and the specialized codes are at varying levels of maturity, from recasted legacy codes able to run on advanced architectures to more sophisticated and accurate models and numerics being developed for representation in the next-generation codes. The code projects address the improvement of simulations of weapons systems that predict, with reduced uncertainties, the behavior of devices in the stockpile. In general, the code projects include large-scale, integrated simulation codes needed for (1) Stockpile Stewardship Program (SSP) maintenance, (2) the Life Extension Program (LEP), (3) addressing and closing Significant Findings Investigations (SFIs), and (4) the support of dismantlement processes and future modifications.

Areas include:

  • Engineering and Physics Integrated Codes: Applications codes and supporting frameworks used for SSP activities (such as annual certification), LEPs, and SFIs. Engineering applications codes support analyses such as thermal, structural, and electrical/electromagnetic modeling of weapon components and systems under normal, abnormal, and hostile environments. Manufacturing process codes support casting, welding, forging, and encapsulation operations.
  • Specialized Codes and Libraries: Promising, emerging technologies that are not yet mature enough for use in the modern multiphysics codes, these codes are specialty codes that simulate relevant complex processes in unique environments, and supporting codes that are closely tied to user applications for problem setup and analysis. This suite of codes changes as new methods are explored and new application-specific requirements are identified.
  • Applications and Algorithms Research: Research to investigate and develop algorithms, computational methods, and future physics, engineering, and numerical simulation technologies. This research enables advances toward greater predictive capability by focusing on overcoming critical obstacles in integrated codes (for example, the need for robust and efficient solvers, design and optimization algorithms, and innovations that improve code effectiveness). Exploratory efforts include short-term focused research projects, as well as longer term, more innovative efforts aimed at large challenges.
  • Applications and Algorithms Research for Next-Generation Platforms: Research to investigate how other areas within Integrated Codes will exploit the next generation of platforms, including new technologies for massive parallelism both on-node (for example, GPUs and large number of threads) and off-node (for example, many nodes operating in parallel and new input/output technologies), as well as new programming models and resilient application codes.

NIF laser filamentation simulation using the PF3D code.