Board Thread:Questions and Answers/@comment-121.222.206.104-20131226232511/@comment-23270394-20131227053902

Short answer: A nuclear reactor

Its kind of complicated, but the basic idea is that if you place an isotope cell next to a uranium cell and start the reactor, the isotope cell will start to recharge. This is called a breeder reactor.

If you don't already use it, the ic2 reactor planner will help in setting up all all reactors, including breeders.

Here is the link: http://www.talonfiremage.pwp.blueyonder.co.uk/v3/reactorplanner.html

Here is a video explaining breeder reactors: https://www.youtube.com/watch?v=Xwaiot0LU7Q