https://www.vice.com/en_us/article/88qp5k/the-us-cant-make-enough-plutonium-triggers-for-its-nuclear-warheads

American power relies on the constant threat of nuclear annihilation. One of the reasons the U.S. military is so powerful is that the country is sitting on more than 5,000 potential world-ending nuclear weapons. But those nukes are aging and America hasn’t been building more. The Pentagon’s goal is to spin up production and make 80 plutonium pits—the trigger mechanism for nukes—a year by 2030. A new report from federal investigators said that’s a pipe dream.

A nuclear pit is a hollow ball of plutonium. On a basic level, nuclear weapons work by surrounding one of these balls with high explosives. When the high explosives go off, they apply uniform pressure to the plutonium pit and cause a nuclear explosion. They are a key ingredient in nuclear weapons, but America hasn’t made a new one since 1989.