If nothing else, consider this. If all it takes to cause a 3-5MT explosion is to get uranium hot and poor water on it, why would anyone go to the effort of developing a more complex weapon? The entire Manhattan project could have been easily solved if it was this simple, and even then the Fat Man and Little Boy bombs only yielded between 13-22kT. It wasn't until 7 years after WWII that the US managed to conduct a test that broke the mega-ton barrier. More complex H-bombs are required for this.
But regardless, we're picking nits here. It's a fun read and I enjoy your stories, so I wasn't intending to pick on you.
But regardless, we're picking nits here. It's a fun read and I enjoy your stories, so I wasn't intending to pick on you.