Here's an idea for you.
You could have ACID mix with URAN to make yellowcake, or uranium oxide.
From here, if it is melted and cooled, it would form fissile uranium, which would act like plutonium in that it would split into two elements and neutrons while under pressure or if it is bombarded by neutrons.
jacob1:
@The-Fall (View Post)
I didn't make realistic heat, savask did. Since it's not finished, he disabled it in the source, I only enabled it and made it an option. You'll have to ask him to do that.