It seems the rivalry that goes back to the “War of Currents” era in the late 1880s continues to play itself out over and over again between Edison’s General Electric and Westinghouse, even in the 21st century.
George Westinghouse and Thomas Edison became adversaries over Edison’s promotion of direct current (DC) for electric power distribution over the alternating current (AC) advocated by Westinghouse (now owned by Toshiba) and Nikola Tesla. Edison’s low-voltage distribution system using DC ultimately lost to AC.
Jack Bailey, vice president, nuclear generation, at Tennessee Valley Authority explains why his organization finally decided on the Westinghouse AP1000. TVA is part of the NuStart consortium at the Belafonte site in Scottsboro, Ala., where TVA is developing a combined operating license for the Westinghouse AP1000 reactor.
NuStart Energy is a company owned by nine power companies, created in 2004 for the dual purposes of: 1) obtaining a construction and operating license from the Nuclear Regulatory Commission, using the never before used, streamlined licensing process developed in 1992; and 2) completing the design engineering for the selected reactor technologies.
“First, what do you look for?” Bailey asks. “You look at costs or potential costs, because no one knew what the costs of a new plant were at the time. You look at the risk of the design in terms of how closely it resembles your experience, which means operating as well as maintenance, and whether there are any new features we may not be familiar with.
“So, we were looking at two different designs primarily. We looked at the ESBWR, which was the GE design reactor, the advanced boiling reactor. It was a good design. It had active safety systems like similar plants we have today, and it already had been built. So it was relatively low risk,” he says.
“But from a cost point of view, it would be a little bit higher because of all of the active safety systems and the extra concrete it would take to build it, he says. Furthermore, at the time there was an additional risk in that the rest of the utilities looking at new nuclear plants were not interested in building an ESBWR.
“This was before South Texas decided to go down that path. But at the time we would have been the only U.S. utility that was building that particular design, and therefore we didn’t want to be in a one-of-a-kind position again in the United States, although they had been built in Japan,” Bailey says.
He also saw there were two problems when comparing the economics of GE’s simplified boiling reactor to the Westinghouse design, and there seemed to be potential concerns on the risk side. “One was that [the GE design] introduced natural circulation cooling through the reactor. It doesn’t have forced reactor coolant circulating pumps. And therefore you are relying on just the differentials in temperature for the water to move through the reactor. All of which is technically feasible and has been demonstrated in other applications on a smaller scale, but nothing had been done to the size and scale of that particular reactor design.
“We thought that would introduce some new and unusual discoveries as that path went forward. The other thing was that particular design was further behind in the licensing process than the Westinghouse AP 1000.”
Bailey explains that the AP1000 already had design certification from the Nuclear Regulatory Commission and that licensing risk is a big risk that everybody is worried about for new plants. “Being further down the path with all those reviews already being completed—the certainty of getting through that process was higher with the AP1000 design,” he said.
Furthermore, Westinghouse, he says, had simplified the safety systems for the plant to rely on passive features like gravity draining from the roof of the containment. “That reduces the cost and makes the plant simpler, more reliable in principle, and as a result you meet all of the safety requirements with margin and without having multiple active safety systems to provide those functions.”
Duke Energy’s Turner says his company chose the AP1000 not only for being the best reactor design, but the nuke also presented knowledge transfer opportunities because the utility operated Westinghouse technology at both its McGuire station and Catawba station.
“I think that you have the opportunity for more passive operating mode than you had in earlier designs,” Turner says. “It [uses] fewer pumps, valves, cable and piping. There have also been improvements in terms of how easy it is to operate and how costly it is to maintain. My sense is that because of what happened the last time with a lot of nuclear units that were begun—and some never completed—the cost increases that happened during the process. I think everyone’s sensitivity is heightened now to that issue.”