The hot functional testing of unit 4 at the Vogtle Nuclear Power Plant in Georgia has been completed a few months after the cold hydro testing was completed. This was revealed by the Georgia Power Co. The tests involved heating up the reactor to the extreme pressure and temperature required to split atoms.
The successful completion of the test welcomes the loading of radioactive fuel into the reactor. However, the latter still awaits completion of construction documentation and approval from the U.S. Nuclear Regulatory Commission.
This could take approximately 2 to 3 three months according to Southern Co. The loading of fuel could therefore begin sometime between July and October 2023. The commercial operation of the reactor on the other hand could begin between December 2023 and March 2024.
The Vogtle Electric Generating Plant is a two-unit nuclear power plant that is located in Burke County, Georgia, and is named after a former Southern Company and Alabama board chairman, Alvin Vogtle.
Both of the units have a Westinghouse pressurized water reactor (PWR) with a General Electric steam turbine and electric generator and were completed in 1987 and 1989; they both produce a combined capacity of 2,430 MW.
In March 2013, construction of the third unit of the Vogtle Nuclear Power Plant began and was expected to begin operation in 2016 pending the final issuance of the Combined Construction and Operating License by the NRC however the date has been postponed to 2021.
Basement concrete for the nuclear island was poured officially on March 14 of the same year and by June 2013, the construction schedule had been extended by at least 14 months.
Construction of the fourth unit of the Vogtle Nuclear Power Plant began with the basement poured on November 21.
The Department of Energy approved a US$6.5 billion loan guarantee for Southern Company subsidiary Georgia Power and Oglethorpe Power Corp. The Department of Energy initially demanded a credit subsidy fee, but the demand was ultimately dropped given the financial strength of Southern Co. and the Vogtle project.
Georgia Nuclear Plant reaches milestone in the construction
Bechtel, the company constructing the Vogtle Electric nuclear plant in Waynesboro Georgia reached a construction milestone when they set into place a passive containment cooling water tank.
According to the company, that is the last major lift at the two-unit nuclear power plant, which is operated by Southern Nuclear, a subsidiary of Southern Co. The Vogtle plants’ Units 3 and 4 are the only two nuclear power plants under construction in the U.S.
Bechtel said it has had more than 7,000 workers on the Jobsite, which, counting the permanent jobs that have been created, makes Vogtle the largest jobs-producing construction project in the state of Georgia.
Bechtel has performed both the construction and engineering for more than 80% of the nuclear plants in the United States. Brian Reilly, project director for Bechtel, said setting the tank in a place represents the topping out of Unit 4’s shield building.
The passive containment cooling water tank measures 35 feet tall and has an 85-foot outer diameter. The tank module, which includes outfitting and rigging, weighs 360 tons. The company said the AP1000 plant’s passive safety systems require no operator actions to mitigate potential emergency situations.
This is because they use only natural forces such as gravity, natural circulation, and compressed gas to achieve their safety function. No pumps, fans, diesel, chillers, or other active machinery are used, except for a few simple valves that automatically align and actuate the passive safety systems.
The tank will hold approximately 750,000 gallons of cooling water ready to flow down into the containment vessel in an emergency to help cool the reactor, even if external power is lost. The water can also be directed to top off the spent fuel pool, while the tank itself can be refilled from water stored elsewhere on site.
Cold hydro testing for unit 4 of the Vogtle NPP project complete
The cold hydro testing for unit 4 of the Vogtle NPP nuclear expansion project is complete. This is according to Georgia Power, the largest subsidiary of Southern Company. The latter is one of the USA’s largest generators of electricity.
Speaking on this milestone, Chris Womack, chairman, president, and CEO of Georgia Power said, “The team at the Vogtle 3&4 site continues to make important progress. Consequently, we are moving closer to bringing online the first new nuclear units to be built in the country in over 30 years.
These units are a long-term investment for our state. In addition, they are essential to building the future of energy for Georgia. For the next 6 to 8 decades, they will help us continue to provide clean, safe, reliable, and affordable energy for our customers.”
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Cold hydro testing at unit 4 confirmed the reactor’s coolant system functions as designed. Additionally, they verified the welds, joints, pipes, and other components of the coolant system and associated high-pressure systems do not leak especially when under pressure.
As part of the process, the reactor coolant system was filled with water and pressurized above-normal operating conditions. The pressure was then lowered to normal design pressure while comprehensive inspections were conducted to verify the systems meet design standards.
The completion of cold hydro testing is reportedly required to support hot functional testing, which is projected to start by the end of the first quarter of next year.
Other tests carried out on the Unit 4 reactor
Following the loading of nuclear fuel for Vogtle 3, which is expected to enter service in the first quarter of 2023, in October, the construction team at the site continued to advance through various phases of start-up testing.
In early November, closed vessel testing (CVT) was completed. These verified that the pipes and valves in the unit 4 reactor coolant system were installed as designed. Moreover, they confirmed that the system helps ensure safety systems function properly according to Georgia Power.
Workers installed the reactor vessel head as well as the lower and upper reactor internals and flow restrictors to carry out CVT on the plant’s passive safety systems. The flow restrictors were used during hot functional testing to mimic flow through the reactor core.
Still, in November, the unit 4 turbine was rotated on its turning gear for the first time. This demonstrated the turbine was assembled with quality and that integrated oil systems function as designed. Noteworthy, the main turbine system consists of one high-pressure turbine and four low-pressure turbines.
Rotating the turbines on the turning gear ties in all the oil systems and a significant number of supporting systems in the turbine island. The latter is a separate structure outside of the unit’s nuclear containment building.
Once operational, the turbine will rotate at 1,800 revolutions per minute. It will be propelled by steam produced by the unit’s two steam generators using heat transferred from the nuclear reactor.