The company also said all modules for the Vogtle-3 and -4 nuclear expansion project have now been set following the lifting into place of a massive water tank atop the Unit 4 containment vessel and shield building roof. The placement represents the last major crane lift at the site.
Hot functional testing marks the last series of major tests underway for the new nuclear unit ahead of initial fuel load. Georgia Power said the testing represents a significant step towards operation of the Westinghouse AP1000 reactor, construction of which began in March 2013.
Hot functional testing – expected to take six to eight weeks – is conducted to verify the operation of reactor components and systems together and confirm the reactor is ready for fuel load. As part of the testing, the site team will begin running Unit 3 plant systems without nuclear fuel and advance through the testing process towards reaching normal operating pressure and temperature.
Over the next several weeks, nuclear operators will use the heat generated by the unit’s four reactor coolant pumps to raise the temperature and pressure of plant systems to normal operating levels. Once normal operating temperature and pressure levels are achieved and sustained, the unit’s main turbine will be raised to normal operating speed using steam from the plant.
Hot functional testing was scheduled to begin in January 2021 and fuel loading in April 2021, but Georgia Power said in January it was likely to adjust these dates because of a significant increase in Covid-19 cases and “other productivity challenges”.
The company said it still expects to achieve the November 2021 and 2022 regulatory-approved in-service dates for Units 3 and 4 respectively.
The two Vogtle AP1000 plants are the only two commercial reactor units under construction in the US. The project is about 94% complete for Unit 3 with the total Vogtle-3 and -4 project approximately 88% complete.
Southern Company, of which Georgia Power is a subsidiary, said last year that the cost of the Vogtle station was growing, partly because of the Covid-19 outbreak and the rising number of workers diagnosed with the virus.
Southern forecast it will cost $149m more for its share of the project. It said subsidiary Georgia Power, which owns 45.7% of the Vogtle project, could eventually ask state regulators to charge customers for the increase, press reports in the US said.
Unconfirmed press reports have quoted analysts saying costs for the two Vogtle plants have increased to more than $25bn due to delays related to the nuclear accident at Japan’s Fukushima-Daiichi in 2011 and the 2017 bankruptcy of Westinghouse, the technology supplier and the project’s former lead contractor.
Georgia Power, however, said its share of the total project cost forecast stands at $8.5bn. In 2013 the corresponding figure was $4.8bn. In a 2019 report, the Georgia Public Service Commission said costs could be $17.1bn.
