Neptunium-237 and Neptunium-237 Oxide has been added to the fissionables list!
A quick check from me seems to indicate that in can do slightly lighter nukes with the same yield but orders of magnitude higher cost, due to its better material properties (and of course its higher cost). In reactors it is raw worse than plutonium and in oxide worse than uranium oxide due to lower melting points.
I found this nuke on the steam forums, attributed to someone by the username "Staalby" it is a 10.1Mt nuclear weapon which masses less then the 9.64Mt bomb already up there, it costs 3-4x as much though [snip] I prepose we call this the Staalby bomb after the creator
What about the Esterov bomb, for cost. Although I'm pretty sure everybody has a design like this already
Neptunium-237 and Neptunium-237 Oxide has been added to the fissionables list! ["Scientists! Investigate!"]
Fiine~, it's a really expensive nuke material. But I did notice a fun thing about it. The fusion fuel doesn't exert as much pressure on Np-237 as it does on other materials. Combine that with an Osmium reflector and you get this.