If you mean the magnetic containment storage tank, you're right that I never removed it because I never added it in the first place.
Plasma isn't meant to be stored long-term. If you need to store it, store it before you heat it.
And why would you need to do that? Only possible reason I can see is to act as a sort of battery, which 1. you don't need if you have fusion and 2. would make accumulators completely obsolete, which I don't want to do.