Pergium
From Star Trek : Freedom's Wiki
Pergium is a radioactive element used for power in 23rd century nuclear reactors such as the PXK and in transtator technology. Pergium is used by thousands of worlds as a source of energy. One key source of pergium is the planet Janus VI, where it is mined by a Federation colony in conjunction with the Horta. There were several pergium mines in operation in the Sappora system in the 24th century. The Orion Syndicate was also working its way into the industry in 2375.