In a maze of tunnels 900 feet beneath the Nevada desert, U.S. nuclear weapons scientists have since the 1990s been intermittently agitating flecks of plutonium with chemical high explosives, carefully trying to push them to the brink of a chain reaction capable of yielding nuclear force. In a separate network of underground tunnels about 4,800 miles away, in the northern Russian archipelago Novaya Zemlya in the Arctic Circle, Russia conducts its own such experiments, meant to model the key chemical and physical actions that occur in the runup to a full-blown nuclear explosion, without actually causing one.
Center for Public Integrity 18th June 2019 read more »