The cost to replace steam generators at the newest US nuclear reactor has ballooned to nearly $600 million and took weeks longer than originally expected to be installed this spring when inclement weather prolonged outages at the Watts Bar Unit 2 reactor.
Despite the cost and delays, TVA officials said this week that the new equipment should help ensure the long-term viability of TVA’s latest nuclear unit as a reliable, carbon-neutral energy source for decades to come. With the completion of equipment repairs at Watts Bar on July 1, TVA has now replaced and upgraded all steam generators in its four pressurized water reactors and expects to save time and money during future refueling outages with additional power from new generators.
TVA spokesman Jim Hobson said in a phone interview that TVA’s analysis of the new generators indicates that the utilities will save an estimated $14 million per refueling outage compared to older steam generators. In recognition of TVA’s analysis of steam generators and the performance of GE’s new version of generators, the Nuclear Energy Institute recently presented TVA with the industry’s first innovation award.
“A team of our engineers discovered that alternative steam generators made with improved materials would have a much slower wear rate than original equipment, allowing for fewer frequent inspections, improved safety and lower costs,” TVA President Jeff Layash said during a conference call. With analysts this week. “Our employees have built a culture of continuous improvement, and this award highlights strong results that can be implemented across the nuclear industry.”
Condolences and accusations
Despite industry praise, nuclear power critics said the need to replace steam generators at their Watts Bar Unit 2 less than six years after they became operational is another example of how capital costs for nuclear power plants continue to increase more than originally expected.
In 2007, when TVA decided to revive work on the completion of a second unit at Watts Bar the facility had been working on since 1973, the reactor’s completion cost was projected to be $2.5 billion. But in the end, the unit cost $4.7 billion to complete and get started by 2016.
According to a financial report this week, TVA invested another $590 million to purchase and install the four steam generators inside the Unit 2 reactor, bringing the plant’s total capital cost to more than double what TVA estimated a decade and a half ago.
Sandy Kurtz, a Chattanooga environmental lead active with the Sierra Club and the Blue Ridge Environmental Defense Association, said in a phone interview Friday that nuclear plants are still more expensive than expected and not worth the risks and long-term radioactive waste they make. build up.
“Whats Bar and all the other nuclear plants are very expensive for the radiation and radioactive waste they carry,” she said.
But even with costs doubling, Hobson said the Watts Bar Unit 2 is “still a bargain” as it’s about a third the cost of new reactors being built at Plant Vogtle in Georgia.
“When you think about the amount of carbon-free energy that Watts Bar can produce 24 hours a day, seven days a week at the highest reliability rate in the industry with the highest power factor, we know that these investments are certainly the best,” Hobson said.
The power of television and the military
The nuclear units can run continuously for 18 months, Hobson said, delivering electricity that doesn’t depend on whether the sun shines, the wind blows or it rains to fill water storage tanks.
But Watts Bar Unit 2 was only operating at about 90% of capacity in 2021 due to issues identified with the plant’s original steam generators, which were built decades ago when construction began on the twin reactor facility. With the new units in place, both 1,150MW Watts Bar reactors are operating at 100% of their capacity this summer.
Installing the new generators from TVA required cutting a hole in the Watts Bar containment building to remove the old steam generators and lift the new 425-tonne generators into place using one of the largest cranes in the world. When there were winds as strong as it had been on several days in May, TVA had to put off using the crane, Hobson said.
According to the Nuclear Regulatory Authority, the blackout that began in March was originally scheduled to be completed in mid-May, but was delayed by inclement weather and other storms.
“Removing the original steam generators and installing the upgraded models, each weighing more than 800,000 pounds, was a significant engineering and operational feat,” Liash said. The steam generator replacement project involved more than 4,000 welders and over 850,000 pounds of concrete poured while performing more than 26,000 work activities, including replacing 88 of a total of 193 fuel units2.
In addition to generating power, TVA assists the US Army in radiating tritium-producing combustible absorption rods at Watts Bar. The National Nuclear Security Administration is increasing tritium production at Watts Bar and other civilian nuclear plants, but that production has been delayed this year by a project to replace the steam generator at Watts Bar.
Tritium enhances the power of modern thermonuclear weapons but decays often enough that the National Nuclear Security Administration must regularly replace tritium tanks for every active weapon in the United States’ arsenal. Tritium is harvested from TVA reactors at the Savannah River site in Aiken, South Carolina.
Contact Dave Flessner at [email protected] or 423-757-6340. Follow us on Twitter at @Dflessner1