In the U.S., where construction of new nuclear reactors has stalled for three decades, two separate nuclear projects completed placement of basemat structural concrete for new AP1000 reactors a few days apart this March. SCANA Corp.’s South Carolina Electric & Gas Co. (SCE&G) marked the milestone on March 11 (Figure 2), completing concrete placement of the nuclear island basemat for its V.C. Summer Unit 2 in Fairfield, S.C., while Southern Co.’s Georgia Power completed placement for a nuclear island at its Vogtle Unit 3 nuclear expansion site near Waynesboro, Ga., on March 14 (Figure 3).

2. A long haul. Within one week this March, SCANA Corp. and Southern Co. separately completed placement of nuclear island basemat for the first AP1000 reactors under construction at the V.C. Summer site in South Carolina and the Plant Vogtle site in Georgia. This image shows workers laying the 6-foot-thick basemat for the nuclear island of V.C. Summer Unit 2. The task required about 7,000 cubic yards of concrete to cover an area 250 feet long and 160 feet at its widest section. The pour lasted 51.5 hours. Courtesy: SCE&G

3. Pressing on. Placement of basemat structural concrete for the nuclear island at Vogtle Unit 3 near Waynesboro, Ga., was completed in March. Georgia Power said full outlines of both nuclear islands at Vogtle have been completed to “grade level.” The first full components for erecting the Unit 3 containment vessel are completed and staged for installation once the basemat concrete has cured, including the CR10 cradle and the containment vessel bottom head. Courtesy: Georgia Power

Each company has proposed two Westinghouse AP1000 reactors for its chosen site. The basemat provides a foundation for the containment and auxiliary buildings that are within the nuclear island. About 6 feet thick, it requires 7,000 cubic yards of concrete, taking—in SCE&G’s case at least—51.5 hours of continuous concrete pour to cover a surface totaling about 32,000 square feet. Units 2 and 3 at V.C. Summer are scheduled to enter commercial operation in 2017 and 2018, and Units 3 and 4 at Plant Vogtle are to begin operation in 2017 and 2018.

Sonal Patel is POWER’s senior writer.