The installation represents the final module placement for Unit 3, marking another significant milestone for the project.
The module, known as CB-20, is a major part of the AP1000 reactor’s advanced passive safety system. Standing more than 10 metres tall and weighing more than 325,000 kg, the component will hold more than three million litres 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.
Georgia Power said earlier this month the project to build two new AP1000 plans was 85% complete and direct construction of Unit 3 was 90% complete. Milestones achieved in recent weeks include the placement of the Unit 4 polar crane and containment vessel top, signifying that all major lifts inside the containment vessels for both units were complete.
In April, Georgia Power’s parent company, Southern Company, said the workforce at the Vogtle project was being reduced by about 20% to mitigate the impact of the coronavirus pandemic.
The company said the schedule remains unchanged with in-service dates of November 2021 for Unit 3 and November 2022 for Unit 4.
The project to build the two new units began in 2009. The two plants are the only two commercial reactor units under construction in the US.