S&P Global • 10-26-22 • By Bill Freebairn
The Tennessee Valley Authority will need to build 20 new nuclear units if it is to decarbonize its generating fleet by 2050, President and CEO Jeff Lyash said in an interview Oct. 25.
The federal power producer in February approved a strategy for new nuclear plant deployment that earmarked $200 million for the first stage of a potential expansion of its nuclear capacity. The initial program focuses on planning for a single 300-MW boiling water reactor to be built at the Clinch River Nuclear site near Oak Ridge, Tenn.
The Tennessee Valley Authority, or TVA, is developing a construction permit application for potential submittal to the U.S. Nuclear Regulatory Commission, or NRC; funding preliminary site work; and collaborating on testbeds that will demonstrate some innovative features of the GE-Hitachi Nuclear Energy Inc. reactor design it plans to deploy.
Risks will need to be mitigated before the TVA can move forward, Lyash said during an appearance at the U.S. Nuclear Infrastructure Council’s new nuclear capital conference held in conjunction with the Atlantic Council in Washington, D.C., on Oct. 24.
The TVA has not made a final decision to build even one unit, much less 20. However, Lyash said there does not appear to be a way to decarbonize the TVA fleet without adding nuclear capacity in the coming decades. That is even with the planned addition of 10 GW of solar capacity, new pumped storage and battery storage, Lyash said.
The power producer’s board approved “off-ramps” that would allow it to exit planning for a new nuclear power plant after the initial review or at later points should the risks be deemed too high, Lyash said in the interview.
A key decision will come in the fourth quarter of 2023 or the first quarter of 2024 when the TVA will determine whether to submit the application for a construction permit to the NRC, Lyash said. The CEO noted that this would happen only after developing a detailed cost and schedule estimate and would be followed by ordering long-lead-time components for the first unit. The additional costs of passing to this stage of development would exceed $200 million, Lyash said.
Lyash said small modular reactors, or SMRs, which are simpler and smaller and are designed for more flexible operation, could boost the TVA’s transition away from fossil fuels. The cost and construction time for building reactors of a new design are at a premium, the executive acknowledged, but those costs would decline as more in a series are constructed. “There’s no point in building [just] one,” Lyash said.
Building 20 units would allow the TVA to maintain the percentage of nuclear energy in its power mix at about 40% through 2050, Lyash said. The first unit, if approved, could be online by the early 2030s, with additional units coming online as fast as one per year through 2050.
The TVA selected GE Hitachi’s BWRX-300 design in part because it is based on well-understood boiling water reactor designs. It borrows some innovations from a GE Hitachi reactor, the ESBWR, that has been approved by the NRC even though it has not been built anywhere in the world. “I think the licensing risk and the technology risk is very low,” Lyash said.
The same reactor design was selected by Ontario Power Generation Inc. for deployment at its Darlington station and may be built by Polish chemical company Synthos SA, which is seeking to build units to reduce its reliance on fossil generation.
The TVA and Ontario Power Generation signed an agreement to share information and experience in an effort to smooth the deployment of the SMRs they are building. Lyash said the companies, with GE Hitachi, are building testbeds for some key technology to be used in the BWRX-300, including innovative composite steel-concrete bricks and main steam isolation valves directly attached to the reactor pressure vessel.
Part of the first stage of the TVA’s new nuclear power plan calls for a review of additional sites where SMRs could be deployed across the power producer’s four-state footprint, Lyash said. “If we’re successful with the BWRX-300, we’ll build a fleet of them.”
The TVA holds the only NRC early site permit for SMR deployment at the Clinch River site, where up to four such units could be built. Lyash said different reactor designs could be built as part of the potential 20 units the TVA could deploy by 2050.
The TVA operates the third-largest nuclear fleet in the U.S. with more than 8 GW across seven units.