Aha, I get it. And I like that its kinda nerdy. I dont think majority people will get it though. Just Plutonium would be fine, sounds actually real good and I think searching for plutonium os should be distinct enough (given the fact plutonium is not an element of everyday life). However if you still insist on the shorthand, what I saw people do, have a paragraph explaining what the shortcut means and how to call the os. Something like “the"p-239 stands for plutonium and that is what we call the os - Plutonium” or variant of that. Maybe have it on the homepage even as a part of some baner or simly as second or third element under header.