I am trying to find corps that make plutonium. I only want to create nucs for DEFENSIVE purposes only. How do I find corps that produce it, or any other product?
To make plutonium you first need to produce uranium, then you need to sell the uranium to a weapons grade uranium corporation, then you need to sell the weapons grade uranium to a plutonium corporation. All this is fairly expensive for a small country and as far as being defensive, nukes are not going to defend you against anyone. I'd advise you just build some other type of corporation and you'll make more money.
You can buy uranium and weapons grade uranium on the open market.
Sometimes people will sell you plutonium. It is not common. Strategic corporations and Plutonium corporations usually lose money or make very little. Bartering is more effective.
If you already built the strategic corporation you might be able to borrow the plutonium and send back the first missiles.
You can also invade and take over a country that has plutonium. If you are new to the game that could blowback in a variety of heinous ways. Good luck.