The Tennessee Valley Authority’s newest nuclear power plant is also one of its oldest, and it’s showing its age. TVA’s Watts Bar 2, which came on line six years ago, after construction was mothballed in 1985 during TVA’s nuclear power crisis that shut down the entire fleet, is getting new steam generators. TVA starting building the1,200-MW Westinghouse pressurized water reactor, along with its twin Unit 1, in 1973. The plant was 80% complete.
Ultimately, TVA spent over $12 billion for the two-unit Watts Bar station.
TVA shuttered the unit this spring to replace the elderly steam generators, a problem that plagued many PWRs in the 1980s. The Chattanooga Times Free Press reported this week, “Over the past three months, with the aid of more than 2,000 extra TVA and contract workers on site, four 67-foot-long steam generators have been removed and newer versions” installed. TVA chief nuclear officer Tim Rausch told the newspaper, “The four new steam generators are in place, and all the primary welding to connect the new generators into the plant is complete.”
TVA has begun loading fuel and is scheduled to begin pressure tests of the new equipment soon. The job has cost TVA some $500 million and “is the biggest nuclear refueling and maintenance outage at TVA in nearly a decade since similar steam generators were replaced at the Sequoyah Nuclear Plant,” according to the giant federal power agency.
The six-state power system is in the midst of a major heat wave, with temperatures reaching the high 90s across the service territory, forcing TVA to rely more on its fossil generation at a time when natural gas prices have spiked. TVA passes its gas prices onto its municipal distributors, who must pass them on to consumers, and send the extra money directly to TVA.
The Chattanooga paper commented, “Although TVA has operated its newest reactor at Watts Bar for less than six years, the steam generators being replaced were built in the 1970s using designs that are nearly a half century old. The existing steam generators were found to be built with a metal alloy that has prematurely developed leaks and other problems at other nuclear plants.”
Nuclear engineer and atomic power enthusiast Rod Adams (twitter Atomicrod) tweeted, “I wonder how carefully the steam generators were preserved during the 3 decades when they were installed (1980s) and waiting for the plant to be completed (2016) and operated?”
Chemist, author, and nuclear advocate Meredith Angwin replied, “Alloy 600 has pretty much been replaced by 690. IMO, the main issue was that the holes in the support plates in the early generators were put in a shoddy fashion, and the support plates themselves grew corrosion products that pushed against the tubes and dented them.”
–Kennedy Maize
Twitter (kennedymaize)