Southern Company subsidiary Georgia Power has placed the integrated head package (IHP) atop the Unit 3 reactor vessel at the Vogtle nuclear expansion project near Waynesboro, Ga., marking the latest major milestone in the construction of the first new U.S. nuclear reactors in more than 30 years.
Both Vogtle-3 and Vogtle-4—the other unit under construction at the site—are Generation III+ Westinghouse AP1000 reactors, with regulatory-approved in-service dates of November 2021 for Unit 3, and November 2022 for Unit 4.
Details: The IHP stands 48 feet tall, weighs 475,000 pounds, and contains more than three miles of electrical cables, according to the May 12 announcement from Georgia Power. It includes a lifting rig, seismic restraints for control rod drive mechanisms, support for reactor head vent piping, power cables, cables and a conduit for in-core instrumentation, cable supports, and the cooling shroud assembly. The purpose of the IHP is to reduce outage time and personnel radiation exposure by combining operations associated with movement of the reactor vessel head during refueling outages.
Georgia Power also announced that 12 of the 16 shield building courses of panels that surround the Unit 4 containment vessel have been placed. The shield building is a unique feature of the AP1000 reactor design for Vogtle-3 and -4, providing an additional layer of safety around the containment vessel and nuclear reactor to protect the structure from any potential impacts, the utility said.
Piling up the milestones: Additional key project milestones reported by Georgia Power over the past few months include the following:
Completion of Unit 3 open vessel testing, which demonstrated how water flows from key safety systems into the reactor vessel.
Placement of the polar crane and containment vessel top for Unit 4, representing the completion of all major lifts inside the containment vessels for the new units.
Placement of the 2-million-pound roof of the Unit 3 shield building, which provides an additional layer of safety around the containment vessel and nuclear reactor to protect the structure from any potential impacts.
Final concrete placement inside the Unit 3 containment vessel, allowing for the installation of machinery that will be used to load fuel into the unit.