I think I'm ready to start up my nuclear plant.

Stocking up makes no sense in Factorio, it's more about a steady flow of resources, keeping up with the demand. The stock will mean nothing if you can't keep it up. You should keep a small buffer to compensate for fluctuations, but anything above that is actually just a frozen asset, that could be used more effectively elsewhere. I don't want to be rude, just wanted to point that out. Have a good day fellow Engineer!