The two-unit expansion of the Plant Vogtle nuclear power plant in Georgia reached another milestone March 27, with the placement of the Unit 4 containment vessel top head. Friday’s work comes about one year after the Unit 3 containment vessel top was lifted into place.
“Placement of the Unit 4 top head is a culmination of the hard work and dedication of the Vogtle 3 & 4 team as we continue on the path to operation,” said Glen Chick, executive vice president of Vogtle 3 & 4 Construction. Work on the two reactors is about 84% complete, according to Georgia Power, the lead utility on the project.
Georgia Power in a news release said the containment vessel is a high-integrity steel structure that houses critical plant components. The top head is 130 feet in diameter, 37 feet tall, and weighs almost 1.5 million pounds. The head is comprised of 58 large plates, welded together, each more than an inch and a half thick.
Georgia Power earlier this month ordered the first fuel load for Unit 4.
The two new units at Vogtle are the first in the industry to use the Westinghouse AP1000 advanced pressurized water reactor technology, which allows nuclear cores to be cooled even in the absence of operator interventions or mechanical assistance. The AP1000 is the only Generation III+ reactor to receive Design Certification from the U.S. Nuclear Regulatory Commission (NRC). Units 3 and 4 are the first new nuclear units built in the U.S. in the more than 30 years.
Construction of Vogtle Unit 3 began in March 2013, with work on Unit 4 starting in November of that year. Southern Nuclear and Georgia Power, both subsidiaries of Southern Co., took over management of the construction project in 2017 after Westinghouse’s Chapter 11 bankruptcy. The project has sustained several delays and cost overruns. On its current timeline, Vogtle 3 is scheduled to enter service by November 2021, with Unit 4 coming online by November 2022.
Onsite Medical Clinic Opens
Work at Vogtle has continued with new protocols in place due to the COVID-19 pandemic. Southern Co. last week opened an on-site medical clinic accessible to all workers at the construction site near Waynesboro, Georgia. The medical personnel at the clinic can provide test for COVID-19, and all services are free.
“Across the Southern Company system, we’re focused on protecting the safety and health of our employees and contract workers, including members of the North America’s Building Trades Unions [NABTU],” said Tom Fanning, Southern Co.’s chairman, president and CEO, in a statement released by NABTU. “The rigorous preparations in place at Plant Vogtle have helped us take appropriate actions to respond to the impact of COVID-19.”
There are about 9,000 workers currently at the Vogtle site.
Workers at Vogtle completed placement of a 300-ton polar crane inside the Unit 4 containment vessel prior to the lifting of the containment vessel top head. The polar crane will remain in place, and will be used during refueling outages once the reactor is operating. The crane will be used to disassemble the reactor vessel and remove the reactor vessel’s integrated head package, which weighs about 475,000 pounds and contains more than three miles of specialty electrical cables.
The crane is now part of the project’s Initial Test Program, which includes a team that will run the crane through a variety of tests over the next month to help ensure design requirements are met, and that the crane is fully functional. The crane after testing will be used to assist in construction activities, including the placement of components inside the reactor vessel.
—Darrell Proctor is associate editor for POWER (@DarrellProctor1, @POWERmagazine).