Why does Twiggy and Gina not build a nuclear weapon?

Australia has a land mass, less populated per square metre compared to others despite the arid land areas.

Russia as a lot of land mass to.

Why does Australia not build nuclear weapons to protect us?

I am not talking about 6000 odd like Russia but several could be handy and effective.

How much is a nuclear weapon on the black market?

A nuclear weapon is one way Gina and Twiggy protect their resource wealth in a pragmatic way

Obviously building a nuclear weapon would not be easy but having some nuclear experts could be beneficial