Georgia Power has announced the completion of cold hydro testing for unit 4 of the Vogtle NPP nuclear expansion project. The completion of cold hydro testing is required to support hot functional testing, which is projected to start by the end of the first quarter of 2023.
"The team at the Vogtle 3&4 site continues to make important progress as we move closer to bringing online the first new nuclear units to be built in the country in over 30 years. Completion of cold hydro testing on Unit 4 is another critical milestone along the path to get us there," said Chris Womack, chairman, president and CEO of Georgia Power. "These units are a long-term investment for our state and essential to building the future of energy for Georgia. For the next 60 to 80 years, they will help us continue to provide clean, safe, reliable and affordable energy for our customers, serving generations of Georgians as clean, emission-free sources of energy."
Cold hydro testing at unit 4 confirmed the reactor's coolant system functions as designed and verified the welds, joints, pipes and other components of the coolant system and associated high-pressure systems do not leak when under pressure. As part of the testing, the reactor coolant system was filled with water and pressurised above-normal operating conditions, then lowered to normal design pressure while comprehensive inspections were conducted to verify the systems meet design standards.
Closed vessel testing (CVT), completed in early November, verified that the pipes and valves in the unit 4 reactor coolant system are installed as designed and helps ensure safety systems function properly, Georgia Power said. To carry out CVT on the plant's passive safety systems, workers installed the reactor vessel head as well as the lower and upper reactor internals and flow restrictors which will be used during hot functional testing to mimic flow through the reactor core.
Also in November, the unit 4 turbine was rotated on its turning gear for the first time, demonstrating the turbine was assembled with quality and that integrated oil systems function as designed. 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, which is a separate structure outside of the unit's nuclear containment building. Once operational, the turbine will rotate at 1,800 revolutions per minute, propelled by steam produced by the unit's two steam generators using heat transferred from the nuclear reactor. The turbine blades turn the generator rotor to produce electricity.
Following the loading of nuclear fuel for Vogtle 3 in October, teams at the site have continued to advance through various phases of start-up testing. Vogtle Unit 3 is projected to enter service in the first quarter of 2023.
Construction of Vogtle 3 began in March 2013 and Vogtle 4 in the following November - both Westinghouse AP1000 reactors. Southern Nuclear and Georgia Power, both subsidiaries of Southern Company, took over management of the project to build the units in 2017 following Westinghouse's Chapter 11 bankruptcy. Vogtle 3&4 - totalling 2,200MWe, are the first nuclear units to be built in the USA in more than three decades. However, cost overruns and construction problems have delayed the project.
Image: Vogtle units 3&4 (courtesy of Georgia Power)
