The US no longer produces weapons grade plutonium. Supposedly this is a choice.
It has asked other countries to not produce weapons grade plutonium, and to get rid of the weapons grade plutonium they do have.
The economical way to destroy weapons grade plutonium is to burn it in nuclear reactors, to use it for power, which destroys some of it and irreversibly contaminates the rest with plutonium 240, making it unusable for weapons, though still usable for power.
Unfortunately, the US, in attempting to do so, ran into “massive cost overruns”, which is to say, technological decline. Putting it in breach of its agreements with Russia and Japan.
Under the US-Russian PMDA, originally signed in 2000, both parties agreed to dispose of at least 34 metric tons of weapons grade plutonium, enough to produce 17,000 nuclear bombs.
The US, however, has not disposed of any plutonium, despite spending a lot of money attempting to do so. If you cannot use it, probably cannot make it.
