I also have this same problem. I've tried it on a new map in sandbox and the chem plant does not have the recipe. Not sure what is going on?
Found the issue. It is caused by a conflict with the other nuclear mod called uranium power. The problem was only resolved for me when I removed the other mod completely by hand (toggling it off didn't help). Its a shame they don't play nice together though, I wanted to compare this mod with that one on the same save.