Lawrence Livermore National Laboratory
National Security
As the largest, highest energy laser ever built, the National Ignition Facility (NIF) can create conditions—temperatures of 100 million degrees and pressures that are 100 billion times that of the Earth's atmosphere—similar to those in stars and nuclear weapons. With all of its 192 laser beams complete, NIF is the only facility that can perform controlled, experimental studies of thermonuclear burn, the phenomenon that gives rise to the immense energy of modern nuclear weapons.
The National Ignition Facility will provide researchers with unprecedented experimental access to the physics of thermonuclear burn.
In the 1990s, after the United States ceased underground nuclear testing at the Nevada Test Site, the U.S. Department of Energy created the Stockpile Stewardship Program (SSP) to continue to maintain the reliability and safety of the U.S. nuclear deterrent without the need for full-scale testing. The SSP comprises an ongoing process of surveillance, assessment, refurbishment, and reassessment. The oldest nuclear weapon in the stockpile was added in 1970. Not many people own a 37-year-old car or refrigerator, and those machines are far less complex than a nuclear weapon.
The goal of the Stockpile Stewardship Program is to bring advanced experimental and computational tools to bear on the evaluation and assessment of the weapons in the nuclear stockpile. NIF experiments are an essential component of the nation's stockpile assessment and certification strategy. NIF provides the only process for scientists to gain access to and examine thermonuclear burn. These experiments will also help the nation maintain the skills of nuclear weapons scientists, which is crucial in order to assess the age-related changes that could compromise weapon reliability.
NIF provides unprecedented experimental access to the physics of nuclear weapons. Data from NIF experiments complement testing at other experimental facilities at Livermore and elsewhere. This experimental data helps to inform and validate sophisticated, three-dimensional weapons simulation computer codes and bring about a fuller understanding of important weapon physics.
LLNL's Terascale Simulation Facility houses the Department of Energy Advanced Scientific Computing (ASC) Program's Purple supercomputer, a 100-teraops (trillion operations per second) machine that is one of the fastest in the world. ASC Purple enables 3D simulations with high-fidelity physics models of the performance of a full nuclear weapon system.In effect, NIF allows scientists to separate the pieces of the physics of a nuclear weapon and examine each piece in isolation. Even before all of NIF's 192 laser beams are fully operational, experiments are already investigating physics of importance for the SSP.
Not only will NIF create controlled thermonuclear burn in a laboratory setting, but NIF beams can also be used to create conditions of extremely high energy density in materials. One example is using various arrangements of beams to shock materials and demonstrate how they behave at high temperatures and pressures. High energy density physics plays a critical role in nuclear weapons. Understanding how the many different kinds of materials used in nuclear weapons behave—especially as they age beyond their intended lifetimes—under the extreme environments produced in a thermonuclear reaction is a key part of the SSP mission. NIF also will be used to help address planned and proposed Stockpile Life-Extension programs, which are regularly planned refurbishments of weapon systems to ensure their long-term safety and reliability. Changes to weapons systems for safety and security can have unintended consequences if those changes cannot be fully validated. Full validation is achieved through the combination of experiments using facilities such as NIF and advanced computational modeling.
Along with its central role in the Stockpile Stewardship Program, the NIF & Photon Science Directorate also is contributing to national security through the missions of the Photon Science & Applications (PS&A) program. PS&A's Directed Energy Systems and Technology program element is focused on developing next-generation, laser-based defensive systems, such as the solid-state heat-capacity laser and the tailored-aperture ceramic laser. PS&A also is developing technologies to detect nuclear materials in transportation systems to enhance homeland security (see Mono-Energetic Gamma-ray (MEGA-ray) Source).
