A Uranium Bar is a resource created from a naturally spawned Uranium Ore, it is located in Swamp Personal mines. A Titanium Pick is used to mine Uranium Ore.
Before the Egg Fuser update, Uranium Ores and Bars were absolutely useless. Now, with the Egg Fuser, a Uranium Bar can be used to make a hybrid pet and teleportation portals. (More info later)