The PLA 400 nuke warheads estimate was from the 1990s, mostly thousand-kg weight gravity bombs. The early nuke bombs use heavy core fuel, in 50-200 kg range. The enriched nuke fuel has 25,000 yr half life, thus 50-year lapse does not affect its potency. The modern nuke warheads use very different initiators, it provides millions of degree heat and 100s of thousand kg pressure with just a Coke can size device. Thus the 1 megaton power modern nuke warhead weights less than 100 kg, and needs much less core fuel. Therefore, some countries have converted the massive old bomb core fuel to many much smaller core fuels but with 1000 times more power. If PLA has converted the 400 old heavy nuke bombs into 5 times more modern warheads, a 2000 actively deployed nuke arsenal, 🧐🤔🤨😉😎, is very possible.
