The National Ignition Facility (NIF), the world’s highest-energy laser system, is designed to create the extreme conditions—temperatures of 100 million degrees and pressures 100 billion times that of the Earth’s atmosphere—similar to those in stars and in detonating nuclear weapons. Because it is the only facility that can create the conditions that are relevant to understanding the operation of modern nuclear weapons, NIF is a crucial element of the National Nuclear Security Administration’s science-based Stockpile Stewardship Program (SSP).
When the United States ceased underground nuclear testing in the 1990s, the U.S. nuclear weapons program shifted emphasis from developing new designs to dismantling thousands of existing weapons and maintaining a much smaller enduring stockpile. The nuclear weapons in the U.S. stockpile range in age from more than 20 years to nearly 50 years.The Stockpile Stewardship Program was created, and NIF was charged, with helping maintain the safety, security, and reliability of the U.S. nuclear deterrent without underground testing.
NIF can repeatedly simulate the conditions in an exploding nuclear weapon inside the Target Chamber’s controlled environment, giving dedicated teams of scientists and researchers the ability to reconstitute and improve upon the capabilities of underground testing.
Certifying the Stockpile
NIF experiments are an essential component of the nation’s stockpile assessment and certification strategy because NIF provides the only process for scientists to gain access to and examine thermonuclear burn. NIF weapon-based experiments use extremely tiny amounts of test material—barely visible to the naked eye—and are completely safe.
NIF allows researchers to perform experiments in a controlled environment and at a much higher rate than could have been imagined with underground testing. A problem can be picked apart and individual physics pieces can be studied. Researchers no longer have to attempt to parse information from an underground test with limited diagnostics. Radiation transport also is central to the operation of nuclear weapons. With NIF, researchers can perform detailed radiation-hydrodynamic experiments.
Experiments Inform Simulations
Data from NIF experiments complement testing at other experimental facilities at Livermore and elsewhere. The data help inform and validate sophisticated, three-dimensional weapon simulations designed to improve understanding of important weapon physics. These simulations are part of the National Nuclear Security Administration’s Advanced Simulation and Computing Program.
NIF is 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 weapon 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 (see NIF Experiments Support Warhead Life Extensions).
NIF beams can 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. 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 key.
Along with stockpile stewardship, NIF conducts a variety of experiments for the Department of Defense and other agencies as part of its National Security Applications (NSA) mission.
NIF experiments also help the nation’s educational mission of maintaining the skills of nuclear weapon scientists and training new generations of experts.
“Why Ignition? NIF Experiments and Stockpile Stewardship,” NIF & Photon Science News, June 2018
“Ensuring the Reliability of the U.S. Nuclear Deterrent,” NIF & Photon Science News, September 2017
“Poised to Advance Stockpile Stewardship Research,” NIF & Photon Science News, December 2016
“NIF Wins Plaudits for Stockpile Stewardship Role,” NIF & Photon Science News, October 2015
“Stockpile Stewardship at 20 Years,” Science & Technology Review, July 2015