Georgia Power has announced that the last series of major tests ahead of initial fuel load is under way at the second new nuclear unit at the site near Waynesboro, Georgia.

Vogtle 4 pictured in February (Image: Georgia Power)

Hot functional testing verifies the successful operation of reactor components and systems together and confirms the reactor is ready for fuel load.

Tests are carried out under the temperatures and pressures that the reactor systems will be subjected to during normal operation, but without nuclear fuel inside the reactor. Heat generated by the unit's four reactor coolant pumps will be used to raise the temperature and pressure of plant systems to normal operating levels, Georgia Power said. Once these are achieved and sustained, the unit's main turbine will be raised to normal operating speed using steam from the plant. During the series of tests, nuclear operators will be able to exercise and validate procedures as required ahead of fuel load.

Construction of Vogtle 4 - the second of two Westinghouse AP1000 units at the Vogtle site, already home to two operating pressurised water reactors - began in November 2013. Timelines issued by the company earlier this year have suggested that fuel loading is envisaged in June, and the company says it is projected to enter service in "late fourth quarter 2023 or first quarter 2024".

Vogtle unit 3 reached first criticality earlier this month.

Southern Nuclear will operate the new units on behalf of co-owners Georgia Power, Oglethorpe Power, MEAG Power and Dalton Utilities.