On July 23, 2015, V.C. Summer Unit 2 reached a milestone with the successful placement of the CA-01 module, one of the largest, heaviest, and most complicated modules within the Nuclear Island, also referred to as a super module because it was so large that huge submodules had to be shipped from the manufacturer and final assembly was completed on site in the twelve-story Module Assembly Building. Installation of CA-01 was long delayed due to both regulatory and production hurdles related to the module. It was the first of the US AP1000 reactors under construction to achieve placement of this critical module, beating Vogtle Unit 3 to this milestone, and allowing other construction activities in the Nuclear Island to progress that could not proceed until the module was in place. CA-01 is a large structural module that forms the internal structures of some compartments within the Containment Vessel, including the Steam Generator compartments, Reactor Vessel cavity, and Refueling Canal. The CA-01 Module is the heaviest module on site, weighing 1,200 tons, or 2.4 million pounds. Because of how much it weighs, lifting and placing the CA-01 module into the Unit 2 Nuclear Island resulted in the heaviest lift for the V.C. Summer construction project to date.