...this is the super nuke. It may not look powerful, but once you set it off, it is. It's engineered to let out SOME deuterium oxide before fully detonating, so it's target will be primed for blowing up. To see it in action, copy it into a destructible city, and detonate it.
I know you must have put in a lot of time an effort into this, and I agree, it is quite powerful, but:
1) You might want to remove the label of it being realistic. Modern atomic bombs actually use only 2-4 kilograms of plutonium, the rest being high explosives. This equates to about 4 blocks worth of plutonium, which is not powerful at all.
2) Real nukes don't actually use deuterium. Sorry.
3) I was actually the one who came up with the whole idea of spreading the deuterium before detonation....
I'm afraid it's gone defunct due to the update, but I am working on that. It used a wax shell that busted open when there was even the smallest reaction.