The final module for Georgia Power's Vogtle Unit 3, a massive water tank, has been placed atop the containment vessel and shield building roof at the company's Vogtle 3 & 4 nuclear expansion project near Waynesboro, Georgia. The installation represents the final module placement for Unit 3, marking another significant milestone for the project.
The large module, known as CB-20, is a major part of the AP1000 reactor's advanced passive safety system. Standing 35 feet tall and weighing more than 720,000 pounds, the large component will hold approximately 750,000 gallons of water ready to flow down in the unlikely event of an emergency to help cool the reactor. The water can also be directed into the used fuel pool, while the tank itself can be refilled from water stored elsewhere on site.
The AP1000 plant's passive safety systems require no operator actions to mitigate potential emergency situations. These systems use only natural forces such as gravity, natural circulation and compressed gas to achieve their safety function. No pumps, fans, diesels, chillers or other active machinery are used, except for a few simple valves that automatically align and actuate the passive safety systems.
The modules used for Vogtle units 3 & 4 help streamline the construction process, since they were made in advance of arriving to the project site and ready to be assembled into larger components that make up the nuclear units. Since 2011, major modules have been delivered to the site by rail and truck, and included a range of plant components such as floor and wall sections and supporting structures that surround the containment buildings and reactor vessels. The final major module arrived at the construction site in late 2019, meaning all 1,485 major modules required to complete construction had been manufactured and safely delivered.
The placement of the CB-20 module follows the placement of the Unit 3 integrated head package (IHP) atop the reactor vessel. Standing 48 feet tall, weighing 475,000 pounds and containing more than three miles of electrical cables, the IHP is an integral component that will eventually be used by highly-trained nuclear operators to monitor and control the nuclear reaction that will occur inside the Unit 3 reactor vessel.
Additional milestones achieved over the last few months include:
Historic milestones accomplished over the past year include:
With more than 7,000 workers on site, and more than 800 permanent jobs available once the units begin operating, Vogtle 3 & 4 is currently the largest jobs-producing construction project in the state of Georgia.