Hundreds of above- and below-ground nuclear bombs were detonated there from 1951 until the U.S. began adhering to the Comprehensive Test Ban Treaty in 1992.
Subcritical nuclear tests do not trigger a sustained chain reaction that would create a nuclear explosion.
But officials say they examine how plutonium behaves when hit by high explosives.
They claim they are necessary to ensure the nuclear stockpile remains safe.
But the test drew outrage from the mayors of the A-bombed Japanese cities of Hiroshima and Nagasaki.
Survivors of the bombings and disarmament advocates also denounced what was effectively a U.S. nuclear test.
“It is depressing that the United States cannot understand how atomic bomb survivors feel, despite our repeated protests,” said Hirotami Yamada, 81, secretary general of the Nagasaki Atomic Bomb Survivors Council.
In 1997, Indonesia’s Foreign Minister Ali Alatas remarked at a United Nations meeting, “Unless the nuclear powers desisted from subcritical tests and computer simulations to design new weapons, there could be a resumption of the nuclear arms race and a revival risk of global disaster.”