Not counting tests, we haven't seen one in action in over 80 years. If we could practice this level of caution with AI, that would be a great start.
That's because we built very fast computers to simulate them.
We still have hundreds of nuclear power plants worldwide! There have been some terrible accidents but overall the consequences of nuclear power are much less than fossil fuel electricity generation. And some people wish we hadn't nerfed our ability to build nuclear power plants through over-regulation.
Now of course we shouldn't completely deregulate nuclear power either. As in all things, the middle way.
In the mid-80s the world was estimated to have some 60000+, so 12000 is somewhat of an improvement. Ideally through arms control we could reduce this further, but that's no trivial undertaking.