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 United States ceased underground nuclear testing, and the Department of Energy created the science-based Stockpile Stewardship Program to maintain the safety, security, and reliability of the U.S. nuclear deterrent without full-scale testing.
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 stockpile stewardship. NIF creates conditions—temperatures of 100 million degrees and pressures 100 billion times that of the Earth’s atmosphere—similar to those in stars and detonating nuclear weapons.
NIF is also the only U.S. facility designed to perform experimental studies of fusion ignition and thermonuclear burn, the phenomenon that gives rise to the immense energy of modern nuclear weapons. NIF weapon-based experiments use extremely tiny amounts of test material—barely visible to the naked eye—and are completely safe.
NIF experimental data are used to validate 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 experiments also help the nation’s educational mission of maintaining the skills of nuclear weapon scientists and train new generations of experts.