Clothing requisition Part 6 (Patreon)

Looks like Penny's not ready to be naked at this time! She opts to keep her underwear... much to Rita's disappointment! But no matte -on with the show! At D.A.V.E.'s suggestion, the ladies proceed through the ship toward the final destination - the Arc Fusion Reactor!

So... what is an Arc Fusion Reactor, what exactly does it do, have we seen this before and could D.A.V.E. have some sort of ulterior motive here, beyond wowing Penny...?