TVA announced last week that they will be informing the NRC this month that it successfully passed the first in a series of pressure tests for the new reactor following a series of hot functional tests of plant equipment. The latest structural integrity and integrated leak rate tests involved increasing pressure inside the containment vessel to check welds and other seals to make sure they function as designed.

TVA Chief Nuclear Officer Joe Grimes said the success of the tests “speaks to the impressive quality work done by the construction craft in achieving this objective.”

More than 200 valves, cable penetrations, airlock doors and other openings also were checked without any significant problems being uncovered, TVA spokesman Scott Brooks said.

TVA is continuing startup testing to verify the reliability of all safety-related systems at Watts Bar, including emergency AC power systems, prior to preparing for initial fuel load.

“It is important that we verify the containment vessel provides a tight barrier and has been built to rigorous industry standards,” Mike Skaggs, senior vice president for Watts Bar operation and construction, said in a statement.

At this time, Watts Bar Unit 2 is approximately 99 percent complete and remains on target to become the first new nuclear generation of the 21st century. When online, it will produce 1,150 megawatts (MW) of carbon-free electricity. Combined with the output of the operational Unit 1, the Watts Bar plant will meet the needs of 1.3 million homes.