It's inevitable that if the US is to keep a nuclear arsenal, thousands of new nuclear weapons will have to be manufactured...

... and tested?

The U.S. government could announce to the world a temporary resumption of atmospheric nuclear tests, in violation of several binding treaties, in the name of practical necessity. Such a step would not be taken lightly. A series of tests could be conducted over a few months to test new bomb designs, as well as the older Minutemen and B61s. Those tests could take place at the old Nevada Test Site and in the Pacific.