Russia is developing a giant laser called the Tsar Laser to test its nuclear weapons, according to Russian media reports. The laser, which has yet to be completed, would allow scientists to better understand how nuclear materials degrade over time, and how they perform under the extreme pressures and temperatures of a nuclear detonation. While the United States has had a similar laser system, the National Ignition Facility, for over a decade, Russia has lacked such a system due to limitations in producing large numbers of new explosive cores, called plutonium pits. However, the Tsar Laser could allow it to continue remaking pits and extend the effective lifetime of its nuclear arsenal.
Laser experiments offer the best way to predict how nuclear weapons will perform, especially as the United States has stopped conducting live tests of nuclear weapons since enacting the Comprehensive Nuclear-Test-Ban Treaty in 1992. While supercomputer simulations of warheads detonating can assess their safety and reliability, they still need to be verified through physical testing to ensure that simulations match reality. Laser experiments can also reveal how materials located near the radioactive pits in warheads degrade and react over their many-year lifetimes.
Russia’s development of the Tsar Laser indicates it plans to maintain its nuclear stockpile for a long time to come. The laser’s beam arrays are 40 centimeters across, which poses a significant challenge for making the lenses, as the larger the lens, the greater the chance there will be a defect in it. However, some experts see a slim hope in Russia’s investment in the Tsar Laser. If the laser is completed, it could suggest that Russia thinks it already has enough data from explosive nuclear tests and is investing in a science-based stockpile stewardship program instead.
Russia has significant scientific pedigree and experience as a partner in building large scientific facilities, but it has lost much of the expertise needed in recent years, with scientists moving overseas. Despite this, the Tsar Laser could offer benefits for nuclear weapons engineering components. Vladimir Tikhonchuk, emeritus professor at the Center for Intense Lasers and Applications at the University of Bordeaux, France says that experiments conducted through laser systems are “indispensable” for the development of nuclear components.